✔ 最佳答案
A common esterification is the reaction between a carboxylic acid (in CE, an alkanoic acid) and an alcohol (in CE, an alkanol). For example, propanoic acid (CH3CH2COOH) and methanol (CH3OH) can give an ester called methyl propanoate (CH3CH2COOCH3).
CH3CH2COOH + CH3OH ≒ CH3CH2COOCH3 + H2O
For the reaction in the question, a thiol (trivial name: mercaptan) CH3SH (methanethiol or methyl mercaptan) is used instead of the alcohol CH3OH, a similar reaction would occur.
CH3CH2COOH + CH3SH ≒ CH3CH2COSCH3 + H2O
The S atom comes from the CH3SH.