Method of isolating methacrylic acid

摘要

A method of isolating and recovering methacrylic acid from a methacrylic acid-containing reaction product gas resulting from the vapor-phase catalytic oxidation of isobutylene, tertiary butanol or isobutyraldehyde, which comprises introducing the reaction product gas comprising methacrylic acid and various by-products including high boiling substances at a high temperature of 250 DEG to 300 DEG C. into a cooling zone, rapidly cooling the gas therein to a temperature of not more than 100 DEG C. to condense methacrylic acid and thus isolate methacrylic acid, while also converting the high boiling substances to fumes, thereafter introducing the cooled gas containing said fumes into a venturi scrubber, contacting it therein with an aqueous medium to remove said fumes, finally introducing the treated gas into a methacrylic acid-absorbing zone and absorbing methacrylic acid by absorption into an aqueous medium.