PURPOSE: To recover a carboxylic acid completely and utilize it advantageously, by bringing a gas comprising a vaporous or particulate carboxylic acid exhausted in a process, e.g. carboxylic acid esterification, into contact with a liquid carboxylic acid ester.
CONSTITUTION: A gas containing a vaporous or particulate carboxylic acid, e.g. phthalic, trimellitic, pyromellitic, citric, or adipic acid, (including anhydride) is fed from the inlet pipe 11 (heated or kept warm to prevent carboxylic acid from depositing or sticking). A liquid carboxylic acid ester (preferably the ester of the same carboxylic acid to be recoevered) pumped up from the reservoir 13, is circulated via the pipe 15, dispersed preferably through a helmet-formed dispersing plate rotating freely upon springkling, and brought into contact with the gas.
EFFECT: The recovered carboxylic acid is usable directly as a raw material for its ester without causing environmental pollution.
ASAKUNI NOBORU
KANEDA MASANOBU
KURAKI SHIYOUTAROU
