| 摘要 |
PURPOSE:To produce an alpha-chlorocarboxylic acid useful as an intermediate for pharmaceuticals, in high quality and yield, by chlorinating a carboxylic acid such as isobutyric acid, 2-methylvaleric acid, etc., with chlorine gas using phosphorus oxychloride as a catalyst. CONSTITUTION:An alpha-chlorocarboxylic acid (e.g. alpha-chloroisobutyric acid) is produced by chlorinating a carboxylic acid of formula (R1 and R2 are alkyl or aryl) (e.g. alpha-methylbutyric acid, alpha-phenylpropionic acid, etc.) with chlorine gas in the presence of preferably about 4-6mol% (based on the carboxylic acid) phosphorus oxychloride as a catalyst. EFFECT:The process causes little troubles such as solid precipitation in the subsequent step and has high alpha-selectivity. |
