Catalytic conversion of glucose to 5-hydroxymethylfurfural productions over sulphated Ti-Al2O3 catalysts

Titanium-alumina (Ti-Al2O3) composites with Al/Ti 10 ratio were prepared by a sol-gel method. The catalysts were prepared via three different methods such as solution, hydrothermal, and vapour phase using sulfuric acid, thiourea, and dibenzyl polysulfide (DBPS) as precursors, respectively. Ti-Al2O3 (10) composite material enhanced the isomerization of glucose to fructose. Sulfidation of catalysts played an important role in catalytic conversion of glucose as well as fructose dehydration. Glucose conversion of >97% with 65% of 5-hydroxymethylfurfural (HMF) was achieved using a superior H-SO42-/Ti-Al2O3 (10) catalyst at 170 °C, 200 mg of catalyst, time 4 h, and NaCl-H2O/THF. Inorganic salt like NaCl had a crucial role in final product separation as well as to control the side reaction. The material recycle capability was examined up to 6th cycles using the superior H-SO42-/Ti-Al2O3 (10) catalyst and the activities associated with catalyst physico-chemical properties were analyzed in detail.