Preparation of solid acid catalyst from glucose–starch mixture for biodiesel production

The aim of this work is to study the catalyst prepared by glucose–starch mixture. Assessment experiments showed that solid acid behaved the highest esterification activity when glucose and corn powder were mixed at ratio of 1:1, carbonized at 400 °C for 75 min and sulfonated with concentrated H2SO4 (98%) at 150 °C for 5 h. The catalyst was characterized by acid activity measurement, XPS, TEM and FT-IR. The results indicated that solid acid composed of CS0.073O0.541 has both Lewis acid sites and Broˇnsted acid sites caused by SO3H and COOH. The conversions of oleic acid esterification and triolein transesterification are 96% and 60%, respectively. Catalyst for biodiesel production from waste cottonseed oil containing high free fatty acid (FFA 55.2 wt.%) afforded the methyl ester yield of about 90% after 12 h. The catalyst deactivated gradually after recycles usage, but it could be regenerated by H2SO4 treatment.