摘要
化石资源的过度消耗及其产生的环境污染问题驱动了生物质资源各组分转化为燃料、化学品及材料的发展。传统的生物精炼产业聚焦于碳水化合物的分离、纯化、转化与利用,木质素通常作为副产物,仅有少量转化为低附加值产品。木质素的高值化利用不仅可以为下游工业提供可再生的芳香类碳氢资源,同时可大幅提升当前生物精炼产业链的经济效益。近年来,一种基于“木质素优先”策略,即生物质原料在直接催化处理下优先完成木质素组分降解转化为单分子苯酚化合物,同时保留碳水化合物不参与反应,成为生物质组分分离、抗降解屏障破除及各组分高值化利用的新方案。介绍了国内外课题组在该领域取得的一些研究进展,并从苯酚单体产率、选择性、木质素脱除率及碳水化合物保留率等主要参数入手,详细讨论了催化剂、溶剂及生物质原料等对“木质素优先”策略的影响。同时对该策略存在的问题及解决方案进行了分析,展望了未来的发展方向,以期为木质生物质的高效转化利用提供依据和参考。
A large amount of bio?refinery research efforts have been made for the utilization of renewable biomass to produce fuels,chemicals and bio?materials in response to the environmental concerns and energy security.Lignocellulosic biomass is composed by three constitutive components,i.e.,cellulose,hemicellulose and lignin.Current biorefineries have been geared towards optimal carbohydrate(cellulose and hemicellulose)valorization and biomass pretreatment(such as soda and kraft),aiming at the removal of lignin(and hemicellulose)component to obtain pure cellulose amenable to utilization.Under the harsh conditions,the reactive native lignin undergoes irreversible de?polymerization and re?condensation reactions to form the industry lignin,which is always recognized as a waste product due to its complexity of structure and low chemical reactivity.Lignin represents one of the few renewable sources of aromatic chemicals,which is biosynthesized in the plant cell wall through oxidative radical polymerization from primary monolignols,i.e.,p?coumaryl alcohol(H),coniferyl alcohol(G),and sinapyl alcohol(S).The de?polymerization of lignin into monomeric phenols is suitable for downstream processing,which has become a standpoint of lig?nin valorization.In an attempt to utilize all components of biomass,motivated by both economic and ecologic incentives,the de?polymerization of lignin,which is combined in biomass components fractionation,has come into the spotlight.Recently,the“lignin first”reductive catalytic fractionation(RCF)of biomass became a new bio?refinery paradigm,where the biomass sawdust was treated with a heterogeneous metal catalyst directly.In this process,the native lignin was fragmented into soluble phenolic monomers,dimers and oligomers preferentially through cleaving C—O bonds inβ?O?4 units,next to leaving unreacted carbohydrate components as a solid fraction.Furthermore,the biomass recalcitrance would be broken during RCF,thus making of retained carbohydrate components were amenable to valorization via enzym
作者
宋国勇
SONG Guoyong(Beijing Key Laboratory of Lignocellulosic Chemistry,College of Material Science and Technology,Beijing Forestry University,Beijing 100083,China)
出处
《林业工程学报》
CSCD
北大核心
2019年第5期1-10,共10页
Journal of Forestry Engineering
基金
国家自然科学基金(21776020)
关键词
生物质
木质素
还原催化分离
碳水化合物
单体苯酚
biomass
lignin
reductive catalytic fractionation
carbohydrate
monomeric phenols
