Chemical synthesis
Encyclopedia
In chemistry
, chemical synthesis is purposeful execution of chemical reaction
s to get a product
, or several products. This happens by physical
and chemical manipulations usually involving one or more reactions. In modern laboratory
usage, this tends to imply that the process is reproducible, reliable, and established to work in multiple laboratories.
A chemical synthesis begins by selection of compounds
that are known as reagent
s or reactants. Various reaction types can be applied to these to synthesize the product, or an intermediate product. This requires mixing the compounds in a reaction vessel such as a chemical reactor
or a simple round-bottom flask
. Many reactions require some form of work-up procedure before the final product is isolated. The amount of product in a chemical synthesis is the reaction yield
. Typically, chemical yields are expressed as a weight in gram
s or as a percentage of the total theoretical quantity of product that could be produced. A side reaction is an unwanted chemical reaction taking place that diminishes the yield of the desired product.
The word synthesis in the present day meaning was first used by the chemist Adolph Wilhelm Hermann Kolbe
.
s multiple chemical transformations take place within a single reactant, in multi-component reaction
s up to 11 different reactants form a single reaction product and in a telescopic synthesis one reactant goes through multiple transformations without isolation of intermediates.
is a special branch of chemical synthesis dealing with the synthesis of organic compound
s.
In the total synthesis
of a complex product it may take multiple steps to synthesize the product of interest, and inordinate amounts of time. Skill in organic synthesis
is prized among chemists and the synthesis of exceptionally valuable or difficult compounds has won chemists such as Robert Burns Woodward
the Nobel Prize for Chemistry. If a chemical synthesis starts from basic laboratory compounds and yields something new, it is a purely synthetic process. If it starts from a product isolated from plants or animals and then proceeds to a new compounds, the synthesis is described as a semisynthetic
process.
, in which two or more reactants combine to form a single product. The general form of a direct combination reaction is:
where A and B are element
s or compound
s, and AB is a compound consisting of A and B. Examples of combination reactions include:
4 special synthesis rules:
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, chemical synthesis is purposeful execution of chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
s to get a product
Product (chemistry)
Product are formed during chemical reactions as reagents are consumed. Products have lower energy than the reagents and are produced during the reaction according to the second law of thermodynamics. The released energy comes from changes in chemical bonds between atoms in reagent molecules and...
, or several products. This happens by physical
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
and chemical manipulations usually involving one or more reactions. In modern laboratory
Laboratory
A laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
usage, this tends to imply that the process is reproducible, reliable, and established to work in multiple laboratories.
A chemical synthesis begins by selection of compounds
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
that are known as reagent
Reagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
s or reactants. Various reaction types can be applied to these to synthesize the product, or an intermediate product. This requires mixing the compounds in a reaction vessel such as a chemical reactor
Chemical reactor
In chemical engineering, chemical reactors are vessels designed to contain chemical reactions. The design of a chemical reactor deals with multiple aspects of chemical engineering. Chemical engineers design reactors to maximize net present value for the given reaction...
or a simple round-bottom flask
Round-bottom flask
Round-bottom flasks are types of flasks having spherical bottoms used as laboratory glassware, mostly for chemical or biochemical work. They are typically made of glass for chemical inertness; and in modern days, they are usually made of heat-resistant borosilicate glass...
. Many reactions require some form of work-up procedure before the final product is isolated. The amount of product in a chemical synthesis is the reaction yield
Yield (chemistry)
In chemistry, yield, also referred to as chemical yield and reaction yield, is the amount of product obtained in a chemical reaction. The absolute yield can be given as the weight in grams or in moles...
. Typically, chemical yields are expressed as a weight in gram
Gram
The gram is a metric system unit of mass....
s or as a percentage of the total theoretical quantity of product that could be produced. A side reaction is an unwanted chemical reaction taking place that diminishes the yield of the desired product.
The word synthesis in the present day meaning was first used by the chemist Adolph Wilhelm Hermann Kolbe
Adolph Wilhelm Hermann Kolbe
Adolph Wilhelm Hermann Kolbe was a German chemist. He never used the first two of his given names, preferring to be known as Hermann Kolbe.-Life:...
.
Strategies
Many strategies exist in chemical synthesis that go beyond converting reactant A to reaction product B. In cascade reactionCascade reaction
A cascade reaction or tandem reaction or domino reaction is a consecutive series of intramolecular organic reactions which often proceed via highly reactive intermediates. It allows the organic synthesis of complex multinuclear molecules from a single acyclic precursor. The substrate contains many...
s multiple chemical transformations take place within a single reactant, in multi-component reaction
Multi-component reaction
In chemistry, a multi-component reaction , sometimes referred to as a "Multi-component Assembly Process" , is a chemical reaction where three or more compounds react to form a single product...
s up to 11 different reactants form a single reaction product and in a telescopic synthesis one reactant goes through multiple transformations without isolation of intermediates.
Organic synthesis
Organic synthesisOrganic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
is a special branch of chemical synthesis dealing with the synthesis of organic compound
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...
s.
In the total synthesis
Total synthesis
In organic chemistry, a total synthesis is, in principle, the complete chemical synthesis of complex organic molecules from simpler pieces, usually without the aid of biological processes. In practice, these simpler pieces are commercially available in bulk and semi-bulk quantities, and are often...
of a complex product it may take multiple steps to synthesize the product of interest, and inordinate amounts of time. Skill in organic synthesis
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
is prized among chemists and the synthesis of exceptionally valuable or difficult compounds has won chemists such as Robert Burns Woodward
Robert Burns Woodward
Robert Burns Woodward was an American organic chemist, considered by many to be the preeminent organic chemist of the twentieth century...
the Nobel Prize for Chemistry. If a chemical synthesis starts from basic laboratory compounds and yields something new, it is a purely synthetic process. If it starts from a product isolated from plants or animals and then proceeds to a new compounds, the synthesis is described as a semisynthetic
Semisynthetic
"Semisynthesis" or partial chemical synthesis is a type of chemical synthesis that uses compounds isolated from natural sources as starting materials. These natural biomolecules are usually large and complex molecules...
process.
Other meanings
The other meaning of chemical synthesis is narrow and restricted to a specific kind of chemical reaction, a direct combination reactionCombination reaction
A combination reaction or a synthesis reaction is a general category of a chemical reaction , in which two or more reactants are chemically bonded together to produce a single product. When two or more substances combine to form a single product, it is known as a combination reaction...
, in which two or more reactants combine to form a single product. The general form of a direct combination reaction is:
- A + B → AB
where A and B are element
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. Familiar examples of elements include carbon, oxygen, aluminum, iron, copper, gold, mercury, and lead.As of November 2011, 118 elements...
s or compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s, and AB is a compound consisting of A and B. Examples of combination reactions include:
- 2NaSodiumSodium 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...
+ ClChlorideThe chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
2 → 2 NaClSodium chlorideSodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
(formation of table salt) - SSulfurSulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
+ O2OxygenOxygen 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...
→ SO2Sulfur dioxideSulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
(formation of sulfur dioxide) - 4 FeIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
+ 3 O2OxygenOxygen 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...
→ 2 Fe2O3 (iron rusting) - CO2Carbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
+ H2OWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
→ H2CO3Carbonic acidCarbonic acid is the inorganic compound with the formula H2CO3 . It is also a name sometimes given to solutions of carbon dioxide in water, because such solutions contain small amounts of H2CO3. Carbonic acid forms two kinds of salts, the carbonates and the bicarbonates...
(carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
dissolving and reacting with waterWaterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
to form carbonic acidCarbonic acidCarbonic acid is the inorganic compound with the formula H2CO3 . It is also a name sometimes given to solutions of carbon dioxide in water, because such solutions contain small amounts of H2CO3. Carbonic acid forms two kinds of salts, the carbonates and the bicarbonates...
)
4 special synthesis rules:
- metal-oxide + H2O → metal(OH)
- non-metal-oxide + H2O → oxi-acid
- metal-chloride + O2 → metal-chlorate
- metal-oxide + CO2 → metal carbonate (CO3)
See also
- Chemical engineeringChemical engineeringChemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...
- Organic synthesisOrganic synthesisOrganic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
- Total synthesisTotal synthesisIn organic chemistry, a total synthesis is, in principle, the complete chemical synthesis of complex organic molecules from simpler pieces, usually without the aid of biological processes. In practice, these simpler pieces are commercially available in bulk and semi-bulk quantities, and are often...
- Peptide synthesisPeptide synthesisIn organic chemistry, peptide synthesis is the production of peptides, which are organic compounds in which multiple amino acids are linked via amide bonds which are also known as peptide bonds...
- Methods in Organic SynthesisMethods in Organic SynthesisMethods in Organic Synthesis is a fully searchable online, text and graphical database that is updated weekly with the latest developments in organic synthesis...
- Beilstein databaseBeilstein databaseThe Beilstein database is the largest database in the field of organic chemistry, in which compounds are uniquely identified by their Beilstein Registry Number. The database covers the scientific literature from 1771 to the present and contains experimentally validated information on millions of...