Density functional theory and experimental study of cellulose initial degradation stage under inert and oxidative atmosphere

Abstract

Lignocellulose oxidative degradation at low temperature is an important question in fire disaster and biomass utilization. Experimental and theoretical methods were used to investigate the initial stage of cellulose degradation under inert and oxidative atmosphere. TG-FTIR results show that the initial degradation and peak temperatures were lower in oxidative atmosphere. CO2 became the dominant component under oxidative atmosphere, which was attributed to the oxidation of carbon element. Oxygen promoted the formation of acids and aldehydes (-CO) but decreased the yields of alcohols/ethers (-C-O-). Density functional theory calculation results show that thermal cleavage of glucosidic bond is endothermic reaction. The chemisorption of oxygen with reactive cellulose radical released a great amount of heat that drove cellulose pyrolysis to an exothermic process. The formation of lactone structure is a kind source of CO2. Experimental and theoretical results agree with each other well and a possible cellulose oxidative pyrolysis pathway was put forward.