Effects of diphenylethene on products produced during cornstalk cellulose liquefaction in supercritical ethanol

With 1, 1-diphenylethene (DPE) as the polymerization inhibitor, the effects of DPE concentration (dosage) and reaction temperature on the active fragments transforming to liquefaction products during cellulose liquefaction in supercritical ethanol were investigated using an autoclave. As the DPE concentration increases, the yield of volatile compounds decreases by 25.4%, while the yield of bio-oil increases to 39.8%, and the cellulose conversion rate decreases gradually. With the increasing of reaction temperature, the cellulose conversion rate reaches to 85.5% sharply and the volatile compounds also increases fastly, but the maximum bio-oil yield drops to 34.6%. GC-MS analysis shows that ketones, esters, alkanes, alcohols, acids and the DPE derivatives are dominant platform chemicals in the bio-oil. A lot of active fragments (such as CH₃CH₂-, HO-, H-, CH₃-, etc.) produced from cellulose pyrolysis in supercritical ethanol are trapped by a higher concentration of DPE to form DPE derivatives, which has a strong steric effect on the fragments transforming to platform chemicals. With the increasing of temperature, the enhanced pyrolysis of cellulose by ethanol radicals is more significant in comparison with the inhibition of DPE, resulting in an improvement in the content of platform chemicals.