用苯酐下脚料合成邻苯二甲酸二甲酯

苯酐下脚料经研碎后,在固体超强酸SO42-/MoO3-TiO2催化下,与甲醇直接酯化,经过滤、减压蒸馏可制得邻苯二甲酸二甲酯(DMP)。较佳反应条件为:在搅拌下,w(催化剂)=1.0%,甲醇/苯酐(摩尔比)=2.7:1,反应温度140℃,反应时间3h;减压蒸馏压力≤10.0kPa(绝对压力)。苯酐转化率可达95%以上,催化剂易分离并可重复使用。

PREPARATION OF DIMETHYL PHTHALATE PLASTICIZER FROM PHTHALIC ANHYDRIDE RESIDUE

Dimethyl phthalate was synthesized from the pulverized phthalic anhydride residue by direct esterification with methanol catalyzed by SO42- /MoO3-TiO2 and then by filtration and vacuum distillation. The optimal conditions were found as follows: with the continuous stirring, when w (catalyst) = 1. 0% , n(methanol)/n(phthalate anhydride) = 2. 7∶1, the reaction temperature 140℃, the reaction time 3 h; the esters are distilled off under the pressure ≤10. 0 kPa, the recovery of phthalic anhydride could up to 95%. The catalyst could be separated from the reaction materials easily, and could be reused.