Effect of Different Supported Heteropoly Acid on the Catalytic Hydrothermal Conversion of Cellulose into Formic Acid

Abstract

Cellulose, an abundant biomass, has received considerable attention as a renewable precursor to the formation of valuable chemicals. The overall strategy in this research is to produce formic acid from cellulose by using direct catalytic hydrothermal method. In this study, a heterogeneous catalyst system was developed by preparing different types of HPA on hydrotalcite. The three types of HPA- HT are phosphotungstic acid-hydrotalcite (PTA-HT), phosphomolybdic acid-hydrotalcite (PMA-HT) and silicotungstic acid-hydrotalcite (STA-HT); were prepared by the impregnation method. These prepared catalysts were characterized using FTIR, XRD and FESEM-EDX. The catalytic reaction was carried out in a hydrothermal reactor and the FA production was determined using HPLC-DAD. Comparison was made during the investigation where calcined HT was used for cellulose conversion and compared with each HPA-HT. All three catalysts were successfully impregnated on the calcined HT, as proven by XRD, FTIR, and EDX. According to the finding, PMA-HT give the highest cellulose conversion (48%) and FA yield (9.61%) followed by PTA-HT (32% converted cellulose with 7.35% FA yield) and STA-HT (17% cellulose converted and 2.87%). This phenomena occur due to the acidity and moderate redox properties of molybdenum in PMA. Herein, we reported effects of different HPAs on HT towards FA yield.