Patent ID: 8624066

Claim:
A process for preparing methylmercaptopropionaldehyde in a single reaction unit, comprising, simultaneously: contacting a gaseous mixture comprising acrolein with a liquid mixture comprising methylmercaptopropionaldehyde, methyl mercaptan, a catalyst and methylmercaptopropionaldehyde methyl thiohemiacetal in the reaction unit; absorbing the acrolein from the gaseous mixture into the liquid mixture; reacting the absorbed acrolein with the methyl mercaptan or the methylmercaptopropionaldehyde methyl thiohemiacetal to obtain methylmercaptopropionaldehyde; removing gaseous impurities and by-products from the liquid mixture; and separating the obtained methylmercaptopropionaldehyde product from the reaction unit, directing a portion of the separated product to storage or further processing and recycling the remaining portion to the reaction unit; wherein the methyl mercaptan optionally comprises dimethyl sulfide or dimethyl ether; and wherein a concentration of the methylmercaptopropionaldehyde methyl thiohemiacetal in the liquid mixture is from 1 to 10% by weight.