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Esterification and transesterification of 9(10)‐carboxystearic acid and its methyl esters. Kinetic studies
Author(s) -
Dufek E. J.,
Butterfield R. O.,
Frankel E. N.
Publication year - 1972
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02637579
Subject(s) - transesterification , chemistry , steric effects , alkyl , catalysis , organic chemistry , electrophile , octanol , medicinal chemistry , alcohol , butanol , ethanol , partition coefficient
9(10)‐Carboxystearic acid and its mono‐ and dimethyl esters were esterified and transesterified with 1‐butanol, 2‐methoxyethanol, 2‐chloroethanol, 2,2‐dimethylpentanol, 2‐ethylhexanol and 1‐octanol. Rate studies for the sulfuric acid‐catalyzed esterification of 9(10)‐carboxystearic acid to alkyl 9(10)‐carboxystearate and alkyl 9(10)‐carboalkoxystearate indicate than on an average the terminal carboxyl is approximately 26–27 times more reactive than the branched carboxyl group. Esterification is highly dependent on catalyst concentration. Steric hindrance in 2,2‐dimethylpentanol and the electrophilic character of 2‐methoxyethanol and 2‐chloroethanol markedly retard the rate. In addition to the expected diesters, 2‐chloroethanol yields esters containing extra‐O‐CH 2 CH 2 ‐ groups. The rate of transesterification of the terminal ester group of mono‐ and dimethyl esters of 9(10)‐carboxystearic acid is about two times faster than the rate of esterification of the branched carboxyl group. Transesterification of the branched 9(10)‐ester group is extremely slow.