Reaction Kinetics of Levulinic Acid Synthesis from Glucose Using Bronsted Acid Catalyst

Glucose is the primary derivative of lignocellulosic biomass, which is abundantly available. Glucose has excellent potential to be converted into valuable compounds such as ethanol, sorbitol, gluconic acid, and levulinic acid (LA). Levulinic acid is a very promising green platform chemical. It is composed of two functional groups, ketone and carboxylate groups which can act as highly reactive electrophiles for nucleophilic attack so it has extensive applications, including fuel additives, raw materials for the pharmaceutical industry, and cosmetics. The reaction kinetics of LA synthesis from glucose using hydrochloric acid catalyst (bronsted acid) were studied in a wide range of operating conditions, i.e., temperature of 140-180 oC, catalyst concentration of 0.5-1.5 M, and initial glucose concentration of 0.1-0.5 M. The highest LA yield is 48.34 %wt at 0.1 M initial glucose concentration, 1 M HCl, and temperature of 180 oC. The experimental results show that the bronsted acid catalyst's reaction pathway consists of glucose decomposition to levoglucosan (LG), conversion of LG to 5-hydroxymethylfurfural (HMF), and rehydration of HMF to LA. The experimental data yields a good fitting by assuming a first-order reaction model.