Patent ID: 8759592

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 methylmercapto-propionaldehyde; 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 is in the form of crude methyl mercaptan comprising greater than 87% by weight methyl mercaptan, 1.5 to 5% by weight dimethyl sulfide, 0.2 to 1% by weight dimethyl disulphide, 0 to 3% by weight dimethyl ether, greater than zero to 2% by weight water, and greater than zero to 2% by weight methanol.