2,4,5-三氟苯乙酸的合成

Synthesis of 2,4,5-Trifluorobenacetic Acid

以1,2,4-三氟苯为原料,经氯甲基化、羰基化、水解制得2,4,5-三氟苯乙酸,对原料配比、温度、催化剂用量等因素进行了考察,结果表明,优化的反应条件为:合成2,4,5-三氟苄氯时,m(C6H3F3):m(多聚甲醛)=1.0:0.875～0.865,反应时间10 h;合成2,4,5-三氟苯乙酸时,m(C7H4F3Cl):m(cat)=1:0.275～0.25,反应温度40℃。在此条件下,产品总收率在60%以上,2,4,5-三氟苯乙酸的质量分数在99%以上。

2,4,5-Trifluorobenacetic acid was synthesized from 1,2,4-trichlorobenzene via chloromethylation,carbonylation and hydrolyzation.Results show that the optimization synthesis condition of 2,4,5-trifluorobenzyl chloride are as follows: m(C6H3F3):m(paraformaldehyde)=1.0:0.875～0.865,reaction time: 10 h.And the optimization synthesis condition of 2,4,5-trifluorobenacetic acidis m(C7H4F3Cl):m(cat)=1:0.275～0.25 and thereaction temperature is 40 ℃,under this condition,the total yield is above 60%,the purity is above 99%.The proportion of reactants and dosage of catalyst were discussed.