| 摘要 |
<p>PROBLEM TO BE SOLVED: To produce a highly pure acyloxybenzoic acid in high selectivity and high yield, and further to reuse the mother liquor by reacting a hydroxybenzoic acid with a carboxylic halide in the presence of a specific carboxylic acid, crystallizing the acyloxybenzoic acid as the crystal, and separating the crystal from the mother liquor. SOLUTION: A carboxylic halide of formula I (R1 is a 5-21C alkyl or alkenyl, or the like) is subjected to an esterification reaction with a hydroxybenzoic acid of formula II [(n) is 1-3] in the presence of a carboxylic acid of formula III, and the reaction liquid after the reaction is subjected to crystallization treatment. The objective acyloxybenzoic acid of formula IV [(j) is 1-3; (k) is a number of (n)-(j)] is filtered. An acid-halongenating agent is allowed to act on the mother liquor containing the acyloxybenzoic acid and a carboxylic acid of formula III, to convert the carboxylic acid of formula III into the carboxylic halide of formula I. The reacted mother liquor is recycled to the following esterification reaction to provide the compound of formula III successively. As the result, the highly pure acyloxybenzoic acid is produced in a quantitative yield by using a small amount of the carboxylic acid.</p> |
