Catalytic conversion of cellulose to cellulose acetate propionate (CAP) over SO42-/ZrO2 solid acid catalyst

Abstract

The solid super acid catalyst SO42-/ZrO2 was prepared by impregnation method using ZrO2 as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). Al2O 3 and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and NH3-TPD. In this paper, the effects of concentration of H2SO4 impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that SO42-/ZrO2 successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L H2SO4 and calcined at 500 °C. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at 50 °C for 8 h.