酸性助水溶剂脱除木质素机理分析  

Delignification mechanism study of acid hydrotropes

作　　者：王敏[1] 程金兰[1] 李鑫[1,2] 陆晶晶[1] 尹崇鑫 戴红旗 WANG Min;CHENG Jinlan;LI Xin;LU Jingjing;YIN Chongxin;DAI Hongqi(Jiangsu Provincial Key Laboratory of Pulp and Paper Science and Technology,Jiangsu Co-innovation Center for Efficient Processing and Utilization of Forest Resources,Nanjing Forestry University,Nanjing 210037,Jiangsu,China;Northeast Forestry University,Harbin 150040,Heilongjiang,China;Shandong Century Sunshine Paper Group,Weifang 262400,Shandong,China)

机构地区：[1]南京林业大学江苏省制浆造纸科学与技术重点实验室,南京林业大学江苏省林业资源高效加工利用协同创新中心,江苏南京210037 [2]东北林业大学,黑龙江哈尔滨150040 [3]山东世纪阳光纸业集团有限公司,山东潍坊262400

出　　处：《化工学报》2022年第5期2206-2221,共16页CIESC Journal

基　　金：十三五国家重点研发计划项目(2019YFC1905903);江苏省制浆造纸科学与技术重点实验室开放基金项目(201523)。

摘　　要：系统探讨了酸性助水溶剂对甲苯磺酸(p-toluenesulfonic acid,TSA)和马来酸(maleic acid,MA)分离桉木各组分的工艺过程,并对其中木质素脱除机理进行了研究。通过分析对比两种优化后的工艺发现:(1)两种酸性助水溶剂都可以高效脱除木质素,TSA木质素脱除率为67.94%,MA为65.14%;(2)在相同质量分数下,TSA的木质素脱除率比MA更高;(3)在温和条件下,TSA木质素的β-芳醚键含量比MA的高,随着反应条件的加剧,TSA和MA处理后木质素产品中β-芳醚键含量逐渐减少;(4)两种酸性助水溶剂处理后,纤维素保留率都较高,可保持90%以上;但是半纤维素的降解程度随着反应条件的加剧而增加;(5)酸性助水溶剂质量分数越高,在疏水表面的接触角越小,对木质素的助溶作用越明显,脱除木质素效率越高,溶液中木质素聚集体的粒径越小。综上所述,酸性助水溶剂对木质素的脱除基于润湿溶解、木质素芳醚键断裂、半纤维素降解等的综合作用。相关研究可为后续实现温和条件脱木质素工艺优化及机理提供参考。p-Toluenesulfonic acid(TSA)and maleic acid(MA)are important acid hydrotropes for lignocellulose fractionation in recent years.The delignification mechanism of TSA and MA fractionation of eucalyptus wood chips was studied.The results were as follows:(1)Both acid hydrotropes have high delignification efficiency.The delignification rate of TSA was 67.94%and that of MA was 65.14%;(2)The delignification rate of TSA was higher than that of MA at the same hydrotrope concentration;(3)TSA hydrotropic lignin has higherβ-aryl ether linkage content than that of MA lignin under mild condition,theβ-aryl ether linkage content of acid hydrotrope dissolved lignin was reduced with the increasing fractionation severity;(4)More than 90%cellulose was well retained after fractionation,but the hemicellulose degradation rate increased with the reaction severity;(5)The contact angle decreased with the increasing hydrotrope concentration,so the wetting ability of lignin increased,and delignification rate increased also,the size of lignin aggregate in acid hydrotropes decreased.In conclusion,delignification of hydrotropes is a combined effect of wetting dissolution,aryl-ether linkages cleavage and hemicellulose degradation etc.The research can provide a reference for the process optimization and mechanism of delignification under mild conditions.

关 键 词：酸性助水溶剂 脱木质素 反应动力学 生物质 聚集(作用) 接触角 

分 类 号：TQ352.62[化学工程] O643.12[理学—物理化学]