2,3,4,5-四氟苯甲酸的制备

以四氯邻苯二甲酸酐为原料，经酰亚胺化、氟化、水解和脱羧4步反应合成四氟苯甲酸。研究了相转移催化剂对酰胺化反应、氟化反应的影响以及表面活性剂对水解反应的影响。结果表明，酰亚胺化反应中，采用相转移催化法缩短了反应时间，收率达97．3％；氟化反应中采用杯芳烃作为相转移催化剂，收率达81．2％；水解反应中加入表面活性剂十二烷基苯磺酸钠使反应时间大大缩短，其收率达91％。经过改进，反应总时间由56h缩短至11h，总收率由47、3％提高到64．3％。

Preparation of 2,3,4,5-Tetrafluoro-Benzoic Acid

2,3,4,5-Tetrafluorobenzoic acid was synthesized from tetrachlorophthalic anhydride via imidation, fluorination, hydrolysis and decarboxylation. The influences of phase transfer catalyst on imidation and fluorination, and the influences of surfactants on hydrolysis were studied respectively. Experiment results showed that imidation reaction time decreased when phase transfer catalysis method was used, and the imidation yield was 97.3%. The fluorination yield reached 81.2% when calixarene was chosen as phase transfer catalyst. In the presence of sodium dodecyl benzene sulfonate, hydrolysis reaction time decreased obviously and hydrolysis yield reached 91%. Compared with the literature method, the overall reaction time of the improved method decreased from 56 h to 11 h, and the total yield increased from 47.3 % to 64.3 %.