The paper studied the synthesis of allontoin with glyoxaic acid,urea and filter liquor.Mixed acid as the catalyst,vacuum distilling condensation,the yield could be 53.1%.

• 采用乙醛酸、尿素和回收滤液为原料，混酸为催化剂，经真空蒸馏缩合制得尿囊素。收率达53．1%25。