偏苯三甲酸酐与2-乙基己醇非酸催化酯化合成偏苯三甲酸三(2-乙基己)酯

Synthesis of Tri(2-ethylhexyl)trimellitate from Trimellitic Anhydride and 2-Ethylhexanol by Esterification with Nonacid Catalyst

偏苯三甲酸酐与2-乙基己醇在非酸催化剂作用下,摩尔比为1:4,反应温度210℃,经过3小时醇化反应,经脱醇、脱色、过滤得产品偏苯三甲酸三(2-乙基己)酯。产品酸值小于0.2,皂化值307±3,铂-钴色号小于45。本合成路线较传统的硫酸法不需中和水洗,简化了工艺过程,减少了设备的腐蚀和废水排放等。测得酯化反应为不可逆一级反应,活化能E=76.041kJ/mol,210℃酯化反应速度常数k_(210)=3.503h^(-1)。

The esterification of trimellitic anhydride (TA) with 2-ethylhexanol (EH) was investigated. The process was carried out in the presence of a nonacid catalyst at 210℃ with a mole ratio of 1: 4(TA: EH) for 3 hours to give crude tri (2-ethylhexyl)trimellitate (TOTM). After the removal of the unreacted EH, crude TOTM was decoloured and filtered to obtain pure TOTM. The properties of pure TOTM are as follows: acid value<0.2mgKOH/g; saponification value 307±3; volume resistivity 2.9×10^(12); colour(APHA)<45. Compared with the conventional method using sulfuric acid as the catalyst, the present method is superior in some aspects:needless of neutralization and washing,simplification of process and reduction of corrosion and waste water effluent. It is found that the esterification of TA with Eli is a first order irreversible reaction, with activation energy of 76. 01 kJ/mol and a rate constant at 210℃ of 3. 503 h^(-1).