Kinetic Study of the Hydrothermal Carbonization Reaction of Glucose and Its Product Structures

In order to systematically understand the hydrothermal carbonization reactions and kinetics of glucose at 180 °C, the structures of intermediate and final chemical products were identified, the conversion paths were clarified, and the conversion rates and yields were calculated. By comparing the hydrothermal reaction paths and kinetics of 5-hydroxymethylfurfural (HMF), fructose, and glucose, it is proven that HMF is the most important intermediate and the sole precursor of hydrothermal carbon. The degradation of glucose, fructose, and HMF follows the first-order reaction, and the formation of hydrothermal carbon linearly depends on the conversion of HMF. Approximately 28% of HMF is converted from fructose and ∼72% is from glucose. Also, the hydrothermal reaction time-dependent morphologies and structures of the resulting hydrothermal carbon are compared, and their structures before and after heat treatment are characterized.