PRODUCTION OF ACRYLIC ACID OR METHACRYLIC ACID TERTIARY BUTYL ESTER

摘要

PURPOSE:To produce the titled compound in high yield and purity suppressing the production of by-product, by reacting (meth)acrylic acid with isobutylene in the presence of a strongly acidic ion exchange resin catalyst under a specific temperature condition at a low molar ratio of isobutylene. CONSTITUTION:(Meth)acrylic acid is made to react with isobutylene at 0-20 deg.C (preferably starting the reaction at 15-20 deg.C and decreasing the temperature stepwise to 0-5 deg.C) for 3-15hr in the presence of a strongly acidic ion exchange resin catalyst (e.g. sulfonic acid type resin of styrene-divinylbenzene polymer) at a molar ratio of isobutylene to (meth)acrylic acid of 0.5-2.0, the unreacted isobutylene is separated from the reaction product, the low-boiling compounds are separated and the mixture is supplied to a fractionation column to obtain the objective high-purity compound from the column top. At least a part of the bottom residue of the fractionation column is treated with a thin-film evaporator to remove high-boiling compounds and the recovered unreacted (meth) acrylic acid is recycled to the reaction system.