Pyrolysis mechanism of glucose and mannose: The formation of 5-hydroxymethyl furfural and furfural

• 来源期刊: 能源化学
• 年，卷（期）: 2018,（2）
• 页码范围: 486-501
• 页数: 16页
• 语种: 英文

摘要

Fast pyrolysis of biomass will produce various furan derivatives,among which 5-hydroxymethyl furfural (5-HMF) and furfural (FF) are usually the two most important compounds derived from holocellulose.In this study,density functional theory (DFT) calculations are utilized to reveal the formation mechanisms and pathways of 5-HMF and FF from two hexose units of holocellulose,i.e.,glucose and mannose.In addition,fast pyrolysis experiments of glucose and mannose are conducted to substantiate the computational results,and the orientation of 5-HMF and FF is determined by 13C-labeled glucoses.Experimental results indicate that C1 provides the aldehyde group in both 5-HMF and FF,and FF is mainly derived from Cl to C5 segment.According to the computational results,glucose and mannose have similar reaction pathways to form 5-HMF and FF with D-fructose (DF) and 3-deoxy-glucosone (3-DG) as the key intermediates.5-HMF and FF are formed via competing pathways.The formation of 5-HMF is more competitive than that of FF,leading to higher yield of 5-HMF than FF from both hexoses.In addition,compared with glucose,mannose can form 5-HMF and FF via extra pathways because of the epimerization at C2 position.Therefore,mannose pyrolysis results in higher yields of 5-HMF and FF than glucose pyrolysis.