Carboalkoxylation

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 → MeO₂CC₂H₅

The process is catalyzed by Pd[C₆H₄(CH₂PBu-t)₂]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][4]

2 CH₂=CH−CH=CH₂ + CO + CH₃OH → CH₂=CH(CH₂)₃CH=CHCH₂CO₂CH₃

Hydroesterification

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:[5] Presently, zinc acetate is used as the catalyst:

CH₃CO₂H + C₂H₂ → CH₃CO₂CHCH₂

Further reading

• Schoenberg, A.; Bartoletti, I.; Heck, R. F. (1974). "Palladium-catalyzed carboalkoxylation of aryl, benzyl, and vinylic halides". The Journal of Organic Chemistry. 39 (23): 3318–3326. doi:10.1021/jo00937a003.

References

1. Ahmad, Shahbaz; Bühl, Michael (2021-08-04). "Computational modelling of Pd-catalysed alkoxycarbonylation of alkenes and alkynes". Physical Chemistry Chemical Physics. 23 (30): 15869–15880. Bibcode:2021PCCP...2315869A. doi:10.1039/D1CP02426D. hdl:10023/23678. ISSN 1463-9084. PMID 34318843. S2CID 236472958.
2. Scott D. Barnicki (2012). "Synthetic Organic Chemicals". In James A. Kent (ed.). Handbook of Industrial Chemistry and Biotechnology (12th ed.). New York: Springer. ISBN 978-1-4614-4259-2.
3. J. Grub; E. Löser (2012). "Butadiene". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_431.pub2. ISBN 978-3-527-30673-2.
4. Kiss, Gabor (2001). "Palladium-Catalyzed Reppe Carbonylation". Chemical Reviews. 101 (11): 3435–3456. doi:10.1021/cr010328q. PMID 11840990.
5. Bienewald, Frank; Leibold, Edgar; Tužina, Pavel; Roscher, Günter (2019). "Vinyl Esters". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. pp. 1–16. doi:10.1002/14356007.a27_419.pub2. ISBN 9783527303854.