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
A commercial application is the carbomethoxylation of ethylene to give methyl propionate:[1]
C2H4 + CO + MeOH → MeO2CC2H5The process is catalyzed by Pd[C<sub>6</sub>H<sub>4</sub>(CH<sub>2</sub>PBu-t)<sub>2</sub>]2. Under similar conditions, other Pd-diphosphines catalyze formation of polyethyleneketone.
Methyl propionate ester is a precursor to methyl methacrylate, which is used in plastics and adhesives.[2]
Carboalkoxylation has been incorporated into various telomerization schemes. For example carboalkoxylation has been coupled with the dimerization of 1,3-butadiene. This step produces a doubly unsaturated C9-ester:[3]
2CH2=CH-CH=CH2 + CO + CH3OH → CH2=CH(CH2)3CH=CHCH2CO2CH3
Related to carboalkoxylation is hydroesterification, the insertion of alkenes and alkynes into the H-O bond of carboxylic acids. Vinyl acetate is produced industrially by the addition of acetic acid to acetylene in the presence of zinc acetate catalysts: Presently, zinc acetate is used as the catalyst: