Optimization of catalytic activity of sulfated titania for efficient synthesis of isoamyl acetate by response surface methodology

Abstract

TiO2 nanoparticles were synthesized by sol–gel method using titanium tetraisopropoxide. Sulfate ions were introduced on the titania by impregnation method using sulfuric acid as precursor of sulfate ions. Fourier transform infrared and energy-dispersive X-ray spectroscopy, X-ray fluorescence as well as X-ray diffraction, scanning electron microscopy, and BET methods were used for the characterization of the obtained nanoparticles. The esterification of isoamyl alcohol with acetic acid was investigated to prove the catalytic activity of the TiO2 nanoparticles under solvent-free conditions. Response surface methodology was applied to optimize the effect of some parameters such as the molar ratio of acetic acid to alcohol, catalyst loading, reaction temperature, and reaction time on the yield of the isoamyl acetate. The TiO2 nanoparticles were proved to be an excellent heterogeneous catalyst for isoamyl acetate synthesis under solvent-free conditions affording a high yield of 94 % under the following optimal conditions: molar ratio of acetic acid to alcohol (1:7), catalyst loading (3.2 wt% with respect to the acetic acid), the reaction temperature (130 °C), and the reaction time (300 min).