1. Organic chemistry
    Hydroformylation  Decarbonylation  Reppe chemistry  Oxidative carbonylation  Other reactions 

2. Carbonylation in inorganic chemistry

3. Protein carbonylation

4. References

Carbonylation refers to reactions that introduce carbon monoxide 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.

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, carboxylic acids, and esters.^[1][1] Carbonylations are the basis of two main types of reactions, hydroformylation and Reppe Chemistry.

Hydroformylation

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

RCH=CH₂ + H₂ + CO → RCH₂CH₂CHO

The reaction requires metal catalysts that bind the CO, the H₂, and the alkene, allowing these substrates to combine within its coordination sphere.

Decarbonylation

Many organic carbonyls undergo decarbonylation. A common transformation involves the conversion of aldehydes to alkanes, usually catalyzed by metal complexes:^[2]

RCHO → RH + CO

Reppe chemistry

Reppe Chemistry, named after Walter Reppe, entails addition of carbon monoxide and an acidic hydrogen donor to the organic substrate. Large-scale applications of this type of carbonylation are the Monsanto and Cativa processes, which convert methanol to acetic acid. Acetic anhydride is prepared by a related carbonylation of methyl acetate.^[3] In the related hydrocarboxylation and hydroesterification, alkenes and alkynes are the substrates. This method is used in industry to produce propionic acid from ethylene:

RCH=CH₂ + H₂O + CO → RCH₂CH₂CO₂H

These reactions require metal catalysts, which bind and activate the CO.^[4] In the industrial synthesis of ibuprofen, a benzylic alcohol is converted to the corresponding carboxylic acid via a Pd-catalyzed carbonylation:^[1]

ArCH(CH₃)OH + CO → ArCH(CH₃)CO₂H

H₂C=CH₂ + H₂O + CO → CH₃CH₂CO₂H

Hydroesterification is like hydrocarboxylation, but uses alcohols instead of water.^[6] This reaction is employed for the production of methyl propionate:

C₂H₄ + CO + MeOH → MeO₂CCH₂CH₃

Oxidative carbonylation

2 CH₃OH + 1/2 O₂ + CO → (CH₃O)₂CO + H₂O

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.

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:^[7]

CH₂O + CO + H₂O → HOCH₂CO₂H

The conversion of isobutene to pivalic acid is also illustrative:

(CH₃)₂C=CH₂ + H₂O + CO → (CH₃)₃CCO₂H

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.^[8]

Carbonylation in inorganic chemistry

Metal carbonyls, compounds with the formula M(CO)_xL_y (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.^[9] Inorganic compounds that contain CO ligands can also undergo decarbonylation, often via a photochemical reaction.

Protein carbonylation

The modification of side chains in a few native amino acids such as histidine, cysteine, and lysine in proteins to carbonyl derivatives (aldehydes and ketones) is known as protein carbonylation.^[10] Oxidative stress, often metal catalyzed, leads to protein carbonylation.

References

• Fruit Salad (confectionery)
• Fruits (Aqua Teen Hunger Force)
• Fruits (Aqua Teen Hunger Force episode)
• Fruits Basket characters
• Fruit-scented sage
• Fruits Clipper
• Fruit set
• Fruit Shoots
• Fruit Snacks
• Fruits of a poisonous tree
• Fruits of fascism
• Fruits of Passion
• Fruit soup
• Fruit sticker
• Fruit stickers
• Fruit Stripe gum
• Fruits & Veggies - More Matters
• Fruits & Veggies – More Matters
• Fruit tortricid
• Fruittown, Maine
• Fruittown, Massachusetts
• Fruit Tree Borer
• Fruit Tree (Nick Drake album)
• Fruittrees
• Fruit tree tortrix moth