Patent ID: 6320076
Filing Date: 2001-11-20
Classification: B01J,C07C

Abstract:
A process for the preparation of 2-hydroxy-4-methylthiobutanoic acid comprising:continuously contacting a liquid reaction medium with an acrolein feed stream, said reaction medium containing 3-(methylthio)propanal, methyl mercaptan and a catalyst for the reaction between methyl mercaptan and acrolein;continuously introducing methyl mercaptan into said liquid reaction medium;reacting acrolein and methyl mercaptan in said reaction medium in a continuous reaction zone, thereby producing 3-(methylthio)propanal;continuously withdrawing a 3-(methylthio)propanal reaction product from said continuous reaction zone;contacting 3-(methylthio)propanal produced in said continuous reaction zone with hydrogen cyanide to produce 2-hydroxy-4-(methylthio)butanenitrile;contacting said 2-hydroxy-4-(methylthio)butanenitrile with sulfuric acid to produce a hydrolyzate comprising 2-hydroxy-4-methylthiobutanoic acid.