Chemistry:Carboalkoxylation

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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]

C
2
H
4
+ CO + MeOH → MeO
2
CC
2
H
5

The process is catalyzed by Pd[C
6
H
4
(CH
2
PBu-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 CH
2
=CH–CH=CH
2
+ CO + CH
3
OH → CH
2
=CH(CH
2
)
3
CH=CHCH
2
CO
2
CH
3

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:

CH
3
CO
2
H + C
2
H
2
→ CH
3
CO
2
CHCH
2

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" (in en). Physical Chemistry Chemical Physics 23 (30): 15869–15880. doi:10.1039/D1CP02426D. ISSN 1463-9084. PMID 34318843. Bibcode2021PCCP...2315869A. 
  2. Scott D. Barnicki (2012). "Synthetic Organic Chemicals". in James A. Kent. Handbook of Industrial Chemistry and Biotechnology (12th ed.). New York: Springer. ISBN 978-1-4614-4259-2. 
  3. J. Grub; E. Löser (2012). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_431.pub2. 
  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). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. pp. 1–16. doi:10.1002/14356007.a27_419.pub2.