Preparation method of environment-friendly high-yield allantoin

The invention discloses a preparation method of environment-friendly high-yield allantoin. The preparation method comprises the following steps: S100, adding water, urea and a catalyst into a reactor,carrying out stirring and heating to 55-85 DEG C; S200, dropwise adding a glyoxylic acid aqueous solution, simultaneously carrying out negative pressure dehydration for 6-8 hours, stopping negative pressure dehydration after dropwise adding is finished, and continuing to carry out heat preservation for 6-8 hours; and S300, cooling the reaction mixture to room temperature of 20-25 DEG C, sprayingwith a NaHCO3 solution and water in sequence, drying, and crushing to obtain the allantoin finished product. Therefore, sulfuric acid and sulfamic acid are used as catalysts, the use amount of the catalysts is reduced, the reaction stability is ensured, and the product yield is improved. 本申请公开了一种环保型高收率尿囊素的制备方法包括步骤：S100在反应器中加入水、尿素和催化剂，搅拌加热至55℃～85℃；S200滴加乙醛酸水溶液，同时进行负压脱水，持续6～8小时，滴加完毕，停止负压脱水，继续保温6～8小时后；S300将反应混合物冷却至室温20℃～25℃，先