Carbonylation

Last updated

In chemistry, carbonylation refers to reactions that introduce carbon monoxide (CO) into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbonylation also refers to oxidation of protein side chains.

Contents

Organic chemistry

Several industrially useful organic chemicals are prepared by carbonylations, which can be highly selective reactions. Carbonylations produce organic carbonyls, i.e., compounds that contain the C=O functional group such as aldehydes (−CH=O), carboxylic acids (−C(=O)OH) and esters (−C(=O)O−). [1] [2] Carbonylations are the basis of many types of reactions, including hydroformylation and Reppe reactions. These reactions require metal catalysts, which bind and activate the CO. [3] These processes involve transition metal acyl complexes as intermediates. Much of this theme was developed by Walter Reppe.

Hydroformylation

Hydroformylation entails the addition of both carbon monoxide and hydrogen to unsaturated organic compounds, usually alkenes. The usual products are aldehydes:

The reaction requires metal catalysts that bind CO, forming intermediate metal carbonyls. Many of the commodity carboxylic acids, i.e. propionic, butyric, valeric, etc, as well as many of the commodity alcohols, i.e. propanol, butanol, amyl alcohol, are derived from aldehydes produced by hydroformylation. In this way, hydroformylation is a gateway from alkenes to oxygenates.

Decarbonylation

Few organic carbonyls undergo spontaneous decarbonylation, but many can be induced to do so with appropriate catalysts. A common transformation involves the conversion of aldehydes to alkanes, usually catalyzed by metal complexes: [4]

Few catalysts are highly active or exhibit broad scope. [5]

Acetic acid and acetic anhydride

Large-scale applications of carbonylation are the Monsanto acetic acid process and Cativa process, which convert methanol to acetic acid. In another major industrial process, acetic anhydride is prepared by a related carbonylation of methyl acetate. [6]

Oxidative carbonylation

Dimethyl carbonate and dimethyl oxalate are produced industrially using carbon monoxide and an oxidant, in effect as a source of CO2+. [1]

The oxidative carbonylation of methanol is catalyzed by copper(I) salts, which form transient carbonyl complexes. For the oxidative carbonylation of alkenes, palladium complexes are used.

Hydrocarboxylation and hydroesterification

In hydrocarboxylation, alkenes and alkynes are the substrates. This method is used industrially to produce propionic acid from ethylene using nickel carbonyl as the catalyst: [1]

In the industrial synthesis of ibuprofen, a benzylic alcohol is converted to the corresponding arylacetic acid via a Pd-catalyzed carbonylation: [1]

Acrylic acid was once mainly prepared by the hydrocarboxylation of acetylene. [7]

Synthesis of acrylic acid using "Reppe chemistry"; a metal catalyst is required. Acrylic acid synthesis from acethylene.png
Synthesis of acrylic acid using "Reppe chemistry"; a metal catalyst is required.

Nowadays, however, the preferred route to acrylic acid entails the oxidation of propene, exploiting its low cost and the high reactivity of the allylic C−H bonds.

Hydroesterification is like hydrocarboxylation, but it uses alcohols in place of water. [8]

The process is catalyzed by Herrmann's catalyst, Pd[C6H4(CH2PBu-t)2]2. Under similar conditions, other Pd-diphosphines catalyze formation of polyketones.

Other reactions

The Koch reaction is a special case of hydrocarboxylation reaction that does not rely on metal catalysts. Instead, the process is catalyzed by strong acids such as sulfuric acid or the combination of phosphoric acid and boron trifluoride. The reaction is less applicable to simple alkene. The industrial synthesis of glycolic acid is achieved in this way: [9]

The conversion of isobutene to pivalic acid is also illustrative:

Alkyl, benzyl, vinyl, aryl, and allyl halides can also be carbonylated in the presence carbon monoxide and suitable catalysts such as manganese, iron, or nickel powders. [10]

In the Collman reaction, an iron carbonyl complex serves as both metal catalyst and carbonyl source.

Carbonylation in inorganic chemistry

Metal carbonyls, compounds with the formula M(CO)xLy (M = metal; L = other ligands) are prepared by carbonylation of transition metals. Iron and nickel powder react directly with CO to give Fe(CO)5 and Ni(CO)4, respectively. Most other metals form carbonyls less directly, such as from their oxides or halides. Metal carbonyls are widely employed as catalysts in the hydroformylation and Reppe processes discussed above. [11] Inorganic compounds that contain CO ligands can also undergo decarbonylation, often via a photochemical reaction.

Related Research Articles

<span class="mw-page-title-main">Alcohol (chemistry)</span> Organic compound with at least one hydroxyl (–OH) group

In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl functional group bound to a saturated carbon atom. Alcohols range from the simple, like methanol and ethanol, to complex, like sucrose and cholesterol. The presence of an OH group strongly modifies the properties of hydrocarbons, conferring hydrophilic (water-loving) properties. The OH group provides a site at which many reactions can occur.

<span class="mw-page-title-main">Alkyne</span> Hydrocarbon compound containing one or more C≡C bonds

In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and no other functional groups form a homologous series with the general chemical formula CnH2n−2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature. Like other hydrocarbons, alkynes are generally hydrophobic.

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Organometallic chemistry</span> Study of organic compounds containing metal(s)

Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide, cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal phosphine complexes are representative members of this class. The field of organometallic chemistry combines aspects of traditional inorganic and organic chemistry.

<span class="mw-page-title-main">Aldehyde</span> Organic compound containing the functional group R−CH=O

In organic chemistry, an aldehyde is an organic compound containing a functional group with the structure R−CH=O. The functional group itself can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are a common motif in many chemicals important in technology and biology.

<span class="mw-page-title-main">Thioester</span> Organosulfur compounds of the form R–SC(=O)–R’

In organic chemistry, thioesters are organosulfur compounds with the molecular structure R−C(=O)−S−R’. They are analogous to carboxylate esters with the sulfur in the thioester replacing oxygen in the carboxylate ester, as implied by the thio- prefix. They are the product of esterification of a carboxylic acid with a thiol. In biochemistry, the best-known thioesters are derivatives of coenzyme A, e.g., acetyl-CoA. The R and R' represent organyl groups, or H in the case of R.

A diol is a chemical compound containing two hydroxyl groups. An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified.

In organic chemistry, hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group and a hydrogen atom to a carbon-carbon double bond. This process has undergone continuous growth since its invention: production capacity reached 6.6×106 tons in 1995. It is important because aldehydes are easily converted into many secondary products. For example, the resultant aldehydes are hydrogenated to alcohols that are converted to detergents. Hydroformylation is also used in speciality chemicals, relevant to the organic synthesis of fragrances and pharmaceuticals. The development of hydroformylation is one of the premier achievements of 20th-century industrial chemistry.

In chemistry, homogeneous catalysis is catalysis where the catalyst is in same phase as reactants, principally by a soluble catalyst a in solution. In contrast, heterogeneous catalysis describes processes where the catalysts and substrate are in distinct phases, typically solid-gas, respectively. The term is used almost exclusively to describe solutions and implies catalysis by organometallic compounds. Homogeneous catalysis is an established technology that continues to evolve. An illustrative major application is the production of acetic acid. Enzymes are examples of homogeneous catalysts.

In organic chemistry, hydrocyanation is a process for conversion of alkenes to nitriles. The reaction involves the addition of hydrogen cyanide and requires a catalyst. This conversion is conducted on an industrial scale for the production of precursors to nylon.

The Koch reaction is an organic reaction for the synthesis of tertiary carboxylic acids from alcohols or alkenes. The reaction is a strongly acid-catalyzed carbonylation using carbon monoxide, and typically occurs at high pressures ranging from 50 to 5,000 kPa, often requiring temperatures several hundred degrees higher than room temperature. Generally the reaction is conducted with strong mineral acids such as sulfuric acid, HF or BF3. Large scale operations for the fine chemical industry produce almost 150,000 tonnes of Koch acids and their derivatives annually but also generate a great deal of waste, motivating ongoing attempts to use metal, solid acid, and other novel catalysts to enable the use of milder reaction conditions. Formic acid, which readily decomposes to carbon monoxide in the presence of acids or relatively low heat, is often used instead of carbon monoxide directly; this procedure was developed shortly after the Koch reaction and is more commonly referred to as the Koch–Haaf reaction. This variation allows for reactions at nearly standard room temperature and pressure. Some commonly industrially produced Koch acids include pivalic acid, 2,2-dimethylbutyric acid and 2,2-dimethylpentanoic acid.

In organometallic chemistry, a migratory insertion is a type of reaction wherein two ligands on a metal complex combine. It is a subset of reactions that very closely resembles the insertion reactions, and both are differentiated by the mechanism that leads to the resulting stereochemistry of the products. However, often the two are used interchangeably because the mechanism is sometimes unknown. Therefore, migratory insertion reactions or insertion reactions, for short, are defined not by the mechanism but by the overall regiochemistry wherein one chemical entity interposes itself into an existing bond of typically a second chemical entity e.g.:

<span class="mw-page-title-main">Ammoxidation</span> Chemical process for producing nitriles from ammonia and oxygen

In organic chemistry, ammoxidation is a process for the production of nitriles using ammonia and oxygen. It is sometimes called the SOHIO process, acknowledging that ammoxidation was developed at Standard Oil of Ohio. The usual substrates are alkenes. Several million tons of acrylonitrile are produced in this way annually:

<span class="mw-page-title-main">Organorhodium chemistry</span> Field of study

Organorhodium chemistry is the chemistry of organometallic compounds containing a rhodium-carbon chemical bond, and the study of rhodium and rhodium compounds as catalysts in organic reactions.

In chemistry, decarbonylation is a type of organic reaction that involves the loss of carbon monoxide (CO). It is often an undesirable reaction, since it represents a degradation. In the chemistry of metal carbonyls, decarbonylation describes a substitution process, whereby a CO ligand is replaced by another ligand.

An insertion reaction is a chemical reaction where one chemical entity interposes itself into an existing bond of typically a second chemical entity e.g.:

In organic chemistry, ethenolysis is a chemical process in which internal olefins are degraded using ethylene as the reagent. The reaction is an example of cross metathesis. The utility of the reaction is driven by the low cost of ethylene as a reagent and its selectivity. It produces compounds with terminal alkene functional groups (α-olefins), which are more amenable to other reactions such as polymerization and hydroformylation.

In industrial chemistry, carboalkoxylation is a process for converting alkenes to esters. This reaction is a form of carbonylation. A closely related reaction is hydrocarboxylation, which employs water in place of alcohols

Oxidative carbonylation is a class of reactions that use carbon monoxide in combination with an oxidant to generate esters and carbonate esters. These transformations utilize transition metal complexes as homogeneous catalysts. Many of these reactions employ palladium catalysts. Mechanistically, these reactions resemble the Wacker process.

In organic chemistry, methylenation is a chemical reaction that inserts a methylene group into a chemical compound:

References

  1. 1 2 3 4 W. Bertleff; M. Roeper; X. Sava. "Carbonylation". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_217. ISBN   978-3527306732.
  2. ↑ Arpe, .J.: Industrielle organische Chemie: Bedeutende vor- und Zwischenprodukte, 2007, Wiley-VCH-Verlag, ISBN   3-527-31540-3
  3. ↑ Beller, Matthias; Cornils, B.; Frohning, C. D.; Kohlpaintner, C. W. (1995). "Progress in hydroformylation and carbonylation". Journal of Molecular Catalysis A: Chemical. 104: 17–85. doi:10.1016/1381-1169(95)00130-1.
  4. ↑ Hartwig, J. F. Organotransition Metal Chemistry, from Bonding to Catalysis; University Science Books: New York, 2010.
  5. ↑ Kreis, M.; Palmelund, A.; Bunch, L.; Madsen, R., "A General and Convenient Method for the Rhodium-Catalyzed Decarbonylation of Aldehydes", Advanced Synthesis & Catalysis 2006, 348, 2148-2154. doi : 10.1002/adsc.200600228
  6. ↑ Zoeller, J. R.; Agreda, V. H.; Cook, S. L.; Lafferty, N. L.; Polichnowski, S. W.; Pond, D. M. (1992). "Eastman Chemical Company Acetic Anhydride Process". Catalysis Today . 13: 73–91. doi:10.1016/0920-5861(92)80188-S.
  7. ↑ Takashi Ohara, Takahisa Sato, Noboru Shimizu, Günter Prescher Helmut Schwind, Otto Weiberg, Klaus Marten, Helmut Greim (2003). "Acrylic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_161.pub2. ISBN   978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)
  8. ↑ El Ali, B.; Alper, H. "Hydrocarboxylation and hydroesterification reactions catalyzed by transition metal complexes" In Transition Metals for Organic Synthesis, 2nd ed.; Beller, M., Bolm, C., Eds.; Wiley-VCH:Weinheim, 2004. ISBN   978-3-527-30613-8
  9. ↑ Karlheinz Miltenberger, "Hydroxycarboxylic Acids, Aliphatic" in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim, 2003
  10. ↑ Riemenschneider, Wilhelm; Bolt, Hermann (2000). "Esters, Organic". Ullmann's Encyclopedia of Industrial Chemistry: 10. doi:10.1002/14356007.a09_565. ISBN   978-3527306732.
  11. ↑ Elschenbroich, C. ”Organometallics” (2006) Wiley-VCH: Weinheim. ISBN   978-3-527-29390-2
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.