反应详情

U.S. Pat. No. 4,730,040 uses methyl 5-formylvalerate as a starting material to produce caprolactam. In this process, methyl 5-formylvalerate is first hydrolyzed in the presence of an acidic catalyst at 30° to 200° C. to 5-formylvaleric acid, which is then reacted with excess ammonia and hydrogen in the presence of Raney nickel or Raney cobalt as a hydrogenation catalyst at 50° to 150° C. under superatmospheric pressure to form 6-aminocaproic acid. After the unreacted ammonia and hydrogen gas are removed, the aqueous mixture is heated to 150° to 370° C. under 100 bar to induce dehydrolyzation and cyclization of 6-aminocaproic acid to form caprolactam. Such process is very complicated and the yield is not high enough.