Synthesis of 4-tert-butyl-benzoic acid methyl ester catalyzed by anhydrous iron trichloride

The synthesis of 4 tert butyl benzoic acid methyl ester was performed by methanol and 4 tert butyl benzoic acid using anhydrous iron trichoride as catalyst under fractionating distillation. Factors influencing the reaction were discussed. The best reaction conditions as follow: molar ratio of methanol to 4 tert butyl benzoic acid=5∶1, mass ratio of catalyst to 4 tert butyl benzoic acid 8.4%, reaction time 3 hour, Yield of the product was 92.5%. The results of b.p. determination and index of refraction indicated thah the product was 4 tert butyl benzoic acid methyl ester.