用混合二元酸制备混合酸二甲酯

以工业副产物混合二元酸（DBA）和甲醇为原料，用自制PW12／SiO2作催化剂制备混合酸二甲酯（DME），确定了最佳制备条件：甲醇与DBA摩尔比为3．5，PW12／SiO2加入量（PW12／SiO2中PW12占DBA的质量分数）为2％，反应时间为4．5h，100gDBA中甲苯加入量为50mL。在此最佳条件下，DME收率为84．7％，所得DME为无色澄清液体，其中丁二酸二甲酯的质量分数为11．03％，戊二酸二甲酯的质量分数为13．88％，己二酸二甲酯的质量分数为73．79％。PW12／SiO2具有较好的稳定性和一定的重复使用性，PW12／SiO2重复使用5次时的DME收率仍大于70％。

Preparation of Mixed Dimethyl Esters from Mixed Dibasic Acids

Mixed dimethyl esters(DME)were prepared using by-product mixed dibasic acids (DBA)and methanol as raw materials and self-made PW_(12)/SiO_2 as catalyst.The optimum conditions are as follows:mole ratio of methanol to DBA 3.5,dosage of PW_(12)/SiO_2(mass ratio of PW_(12)to DBA)2%,reaction time 4.5 h and adding 50 mL toluene into 100 g DBA.Under these conditions, the yield of DME is 84.7%.The product DME is a kind of colorless and pellucid liquid containing 11.03% dimethyl succinate,13.88% dimethyl glutarate a...