Phthalonitrile
Encyclopedia
Phthalonitrile is an organic compound with the formula C6H4(CN)2, which is an off-white crystal solid at room temperature. It is a benzene
derivative, containing two adjacent nitrile
groups. The compound is partially soluble in water, and is soluble in acetone
, nitrobenzene
, and benzonitrile
. The molecule is used as a precursor to phthalocyanine
pigments, fluorescent brighteners, and photographic sensitizers.
. While initial yields were small, it was a precursor that eventually to the contemporary large-scale synthesis seen today.
of o-xylene
in the presence of a vanadium oxide-antimony-oxide catalyst over heat (480 oC). This process passes a gaseous mixture of o-xylene, ammonia, and oxygen through a distributor plate into a fluidized bed reactor, containing the catalyst.
pigment, which is a normative precursor to the blue dye in jeans, is generated through the mixing of a metal, a metal halide, or a metal alkoxide in solution with C6H4(CN)2. The reaction is carried out in a solvent at around 180 oC.
Polymers of phthalonitrile have been developed for use in high temperature composite applications, and have attractive properties including a glass transition temperature exceeding 450°C, fire performance that meets MIL-STD-2031, and absence of volatile production during the curing process.
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....
derivative, containing two adjacent nitrile
Nitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...
groups. The compound is partially soluble in water, and is soluble in acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
, nitrobenzene
Nitrobenzene
Nitrobenzene is an organic compound with the chemical formula C6H5NO2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale as a precursor to aniline. Although occasionally used as a flavoring or perfume...
, and benzonitrile
Benzonitrile
Benzonitrile is the chemical compound with the formula C6H5CN, abbreviated PhCN. This aromatic organic compound is colourless, with a sweet almond odour. It is prepared by the dehydration of benzamide, or by the reaction of sodium cyanide with bromobenzene....
. The molecule is used as a precursor to phthalocyanine
Phthalocyanine
Phthalocyanine is an intensely blue-green coloured macrocyclic compound that is widely used in dyeing. Phthalocyanines form coordination complexes with most elements of the periodic table...
pigments, fluorescent brighteners, and photographic sensitizers.
History of synthesis
The first formation of phthalonitrile was reported in 1896 by Johannes Pinnow. It was noted to be a byproduct of the reaction between orthamidobenzonitrile hydrochloride, sodium nitrite, and hydrochloric acid to synthesize orthodicyanodiazoamidobenzene. The first intentional method derived for the synthesis of phthalonitrile appeared in 1907, when phthalamide was boiled with acetic anhydrideAcetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula 2O. Commonly abbreviated Ac2O, it is the simplest isolatable acid anhydride and is a widely used reagent in organic synthesis...
. While initial yields were small, it was a precursor that eventually to the contemporary large-scale synthesis seen today.
Contemporary synthesis
In a single-stage continuous process, phthalonitrile is prepared by the ammoxidationAmmoxidation
In chemistry, ammoxidation is an industrial process for the production of nitriles using ammonia and oxygen. The usual substrates are alkenes. It is sometimes called the Sohio process, acknowledging that ammoxidation was commercialized by Standard Oil of Ohio...
of o-xylene
O-Xylene
o-Xylene is an aromatic hydrocarbon, based on benzene with two methyl substituents bonded to adjacent carbon atoms in the aromatic ring .It is a constitutional isomer of m-xylene and p-xylene....
in the presence of a vanadium oxide-antimony-oxide catalyst over heat (480 oC). This process passes a gaseous mixture of o-xylene, ammonia, and oxygen through a distributor plate into a fluidized bed reactor, containing the catalyst.
Application
The phthalocyaninePhthalocyanine
Phthalocyanine is an intensely blue-green coloured macrocyclic compound that is widely used in dyeing. Phthalocyanines form coordination complexes with most elements of the periodic table...
pigment, which is a normative precursor to the blue dye in jeans, is generated through the mixing of a metal, a metal halide, or a metal alkoxide in solution with C6H4(CN)2. The reaction is carried out in a solvent at around 180 oC.
Polymers of phthalonitrile have been developed for use in high temperature composite applications, and have attractive properties including a glass transition temperature exceeding 450°C, fire performance that meets MIL-STD-2031, and absence of volatile production during the curing process.