Highly selective esterification of tert-butanol by acetic acid anhydride over alumina-supported InCl 3, GaCl 3, FeCl 3, ZnCl 2, CuCl 2, NiCl 2, CoCl 2 and MnCl 2 catalysts

Abstract

Esterification of tert-butanol by acetic anhydride to tert-butyl acetate over InCl 3/Al 2O 3, GaCl 3/Al 2O 3, FeCl 3/Al 2O 3, MnCl 2/Al 2O 3, CoCl 2/Al 2O 3, NiCl 2/Al 2O 3, CuCl 2/Al 2O 3 and ZnCl 2/Al 2O 3 (metal chloride loading = 1.2 mmol g −1) catalysts have been investigated. The yield of tert-butyl acetate obtained was over 99.5%; when the reaction conditions used were as follows: the molar ratio of tert-butanol/acetic acid anhydride = 1.1, the catalysts/( tert-butanol + acetic anhydride) wt. ratio = 0.026, reaction temperature = 30 °C, and reaction time = 2 h. The esterification activity of the alumina supported metal chloride catalysts is in the following order: InCl 3 > GaCl 3 > FeCl 3 > ZnCl 2 > CuCl 2 > NiCl 2 > CoCl 2 > MnCl 2 > Al 2O 3. These catalysts can also be reused in the esterification of tert-butanol for several times. The effect of some factors such as reaction temperature, the amount of used catalyst and reaction time on the esterification has been investigated. InCl 3/Al 2O 3 is highly active, selective and reusable catalyst for the esterification.