PREPARATION OF MONOCHLOROACETIC ACID

摘要

PURPOSE:To prepare the titled compound useful as a raw material of alpha-amino acid, alpha-hydroxy acid, etc., in high conversion and selectivity, by oxychlorinating acetic acid in vapor phase in the presence of a catalyst comprising cupric chloride and a chloride of an VIII-group metal supported on a carrier. CONSTITUTION:The catalyst consisting of cupric chloride and the cocatalyst consisting of at least one chloride of an VIII-group metal (e.g. PtCl4.5H2O) are supported on a carrier such as silica-alumina (preferably having a pore diameter of 100- several hundreds Angstrom ). The amounts of the catalyst and the cocatalyst are preferably 100-300g/l and 5-50g/l, respectively. Acetic acid is subjected to the oxychlorination preferably at 180-300 deg.C under normal pressure - several kg/cm<2>G in the presence of the above catalyst to obtain the objective monochloroacetic acid. The composition of the mixed gas used as the raw material is e.g. 0.5-3 moles of hydrogen chloride and 0.1-1mol of oxygen per 1mol of acetic acid.