3,3,3-三氟-2,2-二甲基丙酸的合成

Synthesis of 3,3,3-Trifluoro-2,2-dimethylpropionic Acid

以自制的2,2-二甲基丙二酸单甲酯为原料,经氟代、水解和酸化反应制备出目标化合物,产率49.6%。分别考察了氟代时间、氟代温度、SF4用量对氟代反应的影响,氟代产物中CH2Cl2含量、水解时间对水解反应进程的影响。适宜的反应条件为：氟代反应时间3 h,氟代反应温度80℃,n（2,2-二甲基丙二酸单甲酯）∶n（SF4）=1∶6;氟代产物中CH2Cl2含量≤0.5%;水解反应时间30 min。

2,2-Dimethyl-malonic acid monomethyl ester was used as raw material. The target compound was synthesized by the reactions of fluoridation,hydrolysis and acidification with an overall yield of 49. 6%. The influence of time,temperature,amount of SF4 on the fluoridation and amount of CH2Cl2,the time on the hydrolysis reaction were investigated. The optimized conditions were as follows： the time of fluoridation was 3 h,the temperature of fluoridation was 80 ℃,n（ 2,2-dimethyl-malonic acid monomethyl ester） ∶ n（ SF4） = 1∶ 6; amount of CH2Cl2≤0. 5%; the time of hydrolysis was 30 min.