Benzophenone
Encyclopedia
Benzophenone is the organic compound
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
with the formula (C
6H
5)2CO
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
in UV-curing applications such as inks, imaging, and clear coatings in the printing
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
followed by hydrolysis of the resulting diphenyldichloromethane
, or by Friedel-Crafts acylation of benzene
with benzoyl chloride
in the presence of a Lewis acid
(e.g. aluminium chloride
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
with air.
. It crosses
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
radical
.
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
and dioxybenzone
are used in some sunscreen
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
has dimethylamino
substituent
s at each para position.
The high-strength polymers PEEK
, polyetherether ketones, are prepared from derivatives of benzophenone.
Image:Benzophenone bottle.jpg|A bottle of benzophenone by Lancaster.
Image:Toluene with sodium-benzophenone.jpg|Toluene is refluxed with sodium
and benzophenone to produce dry, oxygen-free toluene.
Image:Toluene with sodium-benzophenone - brown.jpg|The mixture is still not blue yet indicating that the reaction is not complete.
Image:Toluene with sodium-benzophenone - intense blue.jpg|The intense blue coloration due to the benzophenone ketyl radical shows that the toluene is considered free of air and moisture.
Image:Distillation of dry and oxygen-free toluene.jpg|After the toluene has been thoroughly dried by the sodium and benzophenone, it is distilled at atmospheric pressure under a slight positive pressure of nitrogen to prevent contamination by air into the receiving Schlenk flask.
Image:Solvent_pot.JPG|A solvent pot contains dibutyl ether
dried over sodium
and benzophenone
, which gives it its purple color.
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Benzophenone is the organic compoundOrganic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula (C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
5)2CO
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.
Uses
Benzophenone can be used as a photo initiatorPhotoinitiator
A photoinitiator is any chemical compound that decomposes into free radicals when exposed to light. Photoinitiators are found both in nature and in industry ....
in UV-curing applications such as inks, imaging, and clear coatings in the printing
Printing
Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing....
industry. Benzophenone prevents ultraviolet (UV) light from damaging scents and colors in products such as perfumes and soaps. It can also be added to the plastic packaging as a UV blocker. Its use allows manufacturers to package the product in clear glass or plastic. Without it, opaque or dark packaging would be required.
In biological applications, benzophenones have been used extensively as photophysical probes to identify and map peptide–protein interactions .
Synthesis
Benzophenone can be prepared by the reaction of benzene with carbon tetrachlorideCarbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
followed by hydrolysis of the resulting diphenyldichloromethane
Diphenyldichloromethane
Diphenyldichloromethane is used in the synthesis of tetraphenylethylene-Synthesis:Benzophenone is reacted with phosphorus pentachloride to give diphenyldichloromethane...
, or by Friedel-Crafts acylation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....
with benzoyl chloride
Benzoyl chloride
Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour...
in the presence of a Lewis acid
Lewis acid
]The term Lewis acid refers to a definition of acid published by Gilbert N. Lewis in 1923, specifically: An acid substance is one which can employ a lone pair from another molecule in completing the stable group of one of its own atoms. Thus, H+ is a Lewis acid, since it can accept a lone pair,...
(e.g. aluminium chloride
Aluminium chloride
Aluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron trichloride, giving it a yellow colour. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large...
) catalyst. The industrial synthesis relies on the copper-catalyzed oxidation of diphenylmethane
Diphenylmethane
Diphenylmethane is an organic compound with the formula 2CH2. The compound consists of methane wherein two hydrogen atoms are replaced by two phenyl groups...
with air.
Organic chemistry
Benzophenone is a common photosensitizer in photochemistryPhotochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...
. It crosses
Intersystem crossing
Intersystem crossing is a radiationless process involving a transition between two electronic states with different spin multiplicity.-Singlet and triplet states:...
from the S1 state into the triplet state with nearly 100% yield. The resulting diradical will abstract a hydrogen atom from a suitable hydrogen donor to form a ketyl
Ketyl
A ketyl group in organic chemistry is an anion radical with the general structure C-O. in which an oxygen radical is bonded directly to carbon. This radical is very unstable and appears in chemical reactions as a reactive intermediate...
radical
Radical (chemistry)
Radicals are atoms, molecules, or ions with unpaired electrons on an open shell configuration. Free radicals may have positive, negative, or zero charge...
.
Benzophenone radical anion
Sodium reduces benzophenone to the deeply colored radical anion, diphenylketyl:- Na + Ph2CO → Na+Ph2CO·−
This ketyl is used in the purification of hydrocarbon solvents, because it reacts with water and oxygen to give non-volatile products. The ketyl is soluble in the organic solvent being dried, so it reacts quickly with residual water and oxygen. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. The ketyl radical generally appears blue or purple, depending on the solvent.
Commercially significant derivatives
Substituted benzophenones such as oxybenzoneOxybenzone
Oxybenzone is an organic compound used in sunscreens. It forms colorless crystals that are readily soluble in most organic solvents. A 2008 study by the US Centers for Disease Control and Prevention found the compound to be present in 96.8% of human urine samples analyzed as part of the...
and dioxybenzone
Dioxybenzone
Dioxybenzone is an organic compound used in sunscreen to block UVB and short-wave UVA rays. It is a derivative of benzophenone. It is a yellow powder with a melting point of 68 °C. It is insoluble in water, but moderately soluble in ethanol and isopropanol....
are used in some sunscreen
Sunscreen
Sunblock is a lotion, spray, gel or other topical product that absorbs or reflects some of the sun's ultraviolet radiation on the skin exposed to sunlight and thus helps protect against sunburn...
s. The use of benzophenone-derivatives which structurally resemble a strong photosensitizer has been strongly criticized (see sunscreen controversy
Sunscreen controversy
Sunscreen protects against two common forms of skin cancer, squamous cell carcinoma and basal cell carcinoma , and several sunscreen ingredients protect against tumor development in photocarcinogenicity tests in mice...
).
p,p-bis(N,N-dimethylamino)benzophenone or Michler's ketone
Michler's ketone
Michler’s ketone is an organic compound with the formula of [2NC6H4]2CO. This electron-rich derivative of benzophenone is an intermediate in the production of dyes and pigments, for example Methyl violet. It is also used as a sensitizer...
has dimethylamino
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...
s at each para position.
The high-strength polymers PEEK
PEEK
Polyether ether ketone is a colourless organic polymer thermoplastic used in engineering applications.-Synthesis:PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of...
, polyetherether ketones, are prepared from derivatives of benzophenone.
Gallery
Image:Benzophenone bottle.jpg|A bottle of benzophenone by Lancaster.
Image:Toluene with sodium-benzophenone.jpg|Toluene is refluxed with sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
and benzophenone to produce dry, oxygen-free toluene.
Image:Toluene with sodium-benzophenone - brown.jpg|The mixture is still not blue yet indicating that the reaction is not complete.
Image:Toluene with sodium-benzophenone - intense blue.jpg|The intense blue coloration due to the benzophenone ketyl radical shows that the toluene is considered free of air and moisture.
Image:Distillation of dry and oxygen-free toluene.jpg|After the toluene has been thoroughly dried by the sodium and benzophenone, it is distilled at atmospheric pressure under a slight positive pressure of nitrogen to prevent contamination by air into the receiving Schlenk flask.
Image:Solvent_pot.JPG|A solvent pot contains dibutyl ether
Dibutyl ether
Dibutyl ether is a colourless, neutral, readily flammable liquid of low volatility with a characteristic odour. It is insoluble in water, but miscible with most common organic solvents...
dried over sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
and benzophenone
Benzophenone
Benzophenone is the organic compound with the formula 2CO, generally abbreviated Ph2CO. Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone.-Uses:...
, which gives it its purple color.