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[目的]亚氨基二乙腈法合成双甘膦,为了提高产品收率,在亚氨基二乙腈直接酸解时加入硫酸溶液。[方法]以亚氨基二乙腈为原料,在水溶液中滴加三氯化磷和硫酸酸解、缩合制得双甘膦。考察了三氯化磷、甲醛、硫酸用量及p H终点值对双甘膦收率的影响。[结果]酸解反应中加入硫酸,增强反应体系的酸性强度,提高反应温度,双甘膦收率达94%。[结论]确定最佳的工艺条件为亚氨基二乙腈、水、硫酸、三氯化磷、甲醛的摩尔比为1∶30∶0.3∶1.25∶1.45,中和反应终点控制p H值为1.0。在该条件下,双甘膦收率94%以上,纯度98%以上。用液相色谱和核磁共振对双甘膦进行表征。
[Objective] The synthesis of PMIDA by iminodiacetonitrile method, in order to improve the yield of the product, sulfuric acid solution was added during the direct acid hydrolysis of iminodiacetonitrile. [Method] Using iminodiacetonitrile as raw material, dihydropyrimidine was prepared by dropwise addition of phosphorus trichloride and sulfuric acid in aqueous solution. The effects of phosphorus trichloride, formaldehyde, sulfuric acid and p H end point on the yield of PMIDA were investigated. [Result] Sulfuric acid was added into the acid hydrolysis reaction to enhance the acid strength of the reaction system and increase the reaction temperature. The yield of PMIDA reached 94%. [Conclusion] The optimum process conditions were that the molar ratio of iminodiacetonitrile, water, sulfuric acid, phosphorus trichloride and formaldehyde was 1:30:0.3:1.25:1.45, and the endpoint value of neutralization reaction control p H was 1.0. Under this condition, the yield of PMIDA is above 94% and the purity is over 98%. PMIDA was characterized by liquid chromatography and nuclear magnetic resonance.