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研究了杂多酸对二甘醇脱水环化的催化作用．结果表明，磷钨酸、硅钨酸、硅钼酸具有较高的催化活性，而磷钼酸的催化活性较低．采用TG、IR、GC－MS、电导等测试技术，对正丁胺酸性、杂多阴离子碱度、还原特性的测定及对产物结构的分析．实验发现，如果杂多酸酸性太强、杂多阴离子太软，1，4-二氧六环会进一步异构化，生成2-甲基-1，3-二氧五环．
The catalytic effect of heteropoly acids on dehydration and cyclization of diethylene glycol was studied. The results showed that phosphotungstic acid, silicotungstic acid and silicomolybdic acid have higher catalytic activity, while phosphomolybdic acid has lower catalytic activity. The alkalinity and reduction characteristics of n-butylamine acid and heteropolyanions were determined by TG, IR, GC-MS and conductivity measurements, respectively. The product structure was also analyzed. Experiments found that if the heteropoly acid is too acidic, heteropolyanion is too soft, 1,4-dioxane will be further isomerization, generating 2-methyl-1,3-dioxane.