常压法合成乙内酰脲的研究

Synthesis of Hydantoin Under Atmospheric Pressure

研究了常压环境下Bucherer-Berg’s法合成乙内酰脲。通过调整原料配比、反应温度、反应时间等技术参数,得到的最佳反应条件为:m(羟基乙腈)∶m(水)=8∶100,n(羟基乙腈)∶n(碳酸氢铵)=1∶4;合成过程中二氧化碳的通入流量在投料阶段为0.7 L/min、保温阶段为1.2 L/min;酸化过程中n(硫酸)∶n(羟基乙腈)=1∶2;投料阶段的投料温度为80℃、时间为2 h;反应阶段的反应温度和时间依次为85℃下保温反应2 h、90℃下保温反应2 h。乙内酰脲的最终产率可达93.52%,纯度为98.5%。实现了乙内酰脲的高产率和高纯度的制备,为下一步工业化放大奠定了基础。

Hydantoin was synthesized by Bucherer-Berg’s method under atmospheric pressure. By adjusting various technical parameters such as the ratio of raw materials, reaction temperature and time, the optimum reaction conditions were obtained as follows: the mass ratio of hydroxyacetonitrile to water was 8 ∶100, and the molar ratio of hydroxyacetonitrile to ammonium bicarbonate was 1 ∶4;in the synthesis process, the inflow rate of carbon dioxide was0.7 L/min at the feeding stage and 1.2 L/min at the reaction stage, respectively;the mass ratio of sulfuric acid to hydroxyacetonitrile was 1 ∶2 in the acidification stage;the temperature and time were 80 ℃ and 2 h in the feeding stage, 85 ℃ and 2 h in the first reaction stage, and 90 ℃ and 2 h in the second reaction stage. The final yield of hydantoin was 93.52% and its purity was 98.5%. The high yield and purity of ethanolide were achieved in this work,which paves the way for the next stage of industrial amplification.