The effect of polyethylene glycol addition on the synthesis of solid acid catalyst and its applications in esterification reaction

Abstract

Synthesis of a catalyst by a sol-gel method is commonly conducted using a template to form pores to increase the number of active sites. In this work, mesoporous silica-carbon composites were prepared by sol-gel method using polyethylene glycol (PEG) 6000 as the template. Sodium silicate, commercially known as water glass, a cheap material, was used as the silica source. Here, PEG 6000 served as both the carbon source and the template. The silica-PEG composite was then carbonized at 550°C for 1 h to obtain silica-carbon composite. The sulfonate group was grafted into the composite by sulfonation with sulfuric acid at 100°C for 5 h. The sulfonated silica-carbon catalyst had a surface area of approximately 1490.8 m2/g. The very high surface area was able to hold a large amount of sulfonate group resulting an ion capacity of approximately 2.09. The composite was successfully be used as heterogeneous catalyst for esterification of acetic acid with ethanol with a conversion of 90.27%, higher than that of commercially Flotrol F-007.