在Ru/C和甲酸(甲酸盐)体系中碱木质素水热解聚特性研究  

Hydrothermal Depolymerization Characteristics of Alkali Lignin in Ru/C and Formic Acid/Formate System

作　　者：李霄虹 武书彬[1] 

机构地区：[1]华南理工大学制浆造纸工程国家重点实验室,广东广州510640

出　　处：《林产化学与工业》2016年第3期43-52,共10页Chemistry and Industry of Forest Products

基　　金：国家自然科学基金项目(31270635);国家973计划项目(2013CB228101);中央高校基本科研业务费资助(2014ZP14)

摘　　要：在Ru/C和甲酸（甲酸盐）的共同作用下,275~350℃的亚临界水中,进行碱木质素的水热解聚反应。通过GC-MS定性分析和GC-FID定量分析,探究了供氢试剂及用量、反应温度、木质素分子级分对木质素水热解聚的影响。结果表明：在甲酸和Ru/C条件下,木质素解聚液相产物得率最高,组成较简单,具有较好催化降解效果;在甲酸添加量为0.8 mol/L,反应30 min时,木质素解聚液相产物最多,其中含量最高的单酚类物质为4-甲基愈创木酚,在主要单酚类物质中占32.77%,木质素水热解聚液相产物得率随温度升高而先增后减,并在325℃时取得峰值;L1、L2和L3是碱木质素的3个不同的分子级分,L1级分对木质素解聚液相产物得率贡献最大,达61.80%,且产物中单酚类物质总得率最高,为112.71 mg/g。其中,愈创木酚与4-甲基愈创木酚所占比例最高,可分别为35.38和35.52 mg/g;对木质素进行分级分离处理后再进行水热转化反应,有利于液相产物和单酚类物质得率的进一步提高。Hydrothermal depolymerization of lignin were conducted in catalytic system of formic acid/formate and Ru/C at 275-350 ℃.The effects of hydrogen donator type and dosage,temperature,different fractions of alkali lignin on hydrothermal depolymerization were investigated by GC-MS and GC-FID.The results showed that the best catalytic effect with highest liquid product yield was realized when the degradation was conducted in the co-catalyst system of formic acid and Ru/C,and the component of liquid product（LP） was relatively simple.The yield of LP achieved the maximum when the dosage of formic acid was 0.8 mol/L.Furthermore,as the most monomer phenols in LP,4-methyl guaiacol gained a 32.77 % share.With the rising reaction temperature,the yield of LP increased at first and then decreased,and peaked at 325 ℃.L1,L2 and L3 were three different fractions of alkali lignin.Among them,L1 made the 61.80% contribution to the yields of LP,and the maximum total yield of main monomer phenols,i.e.,112.71 mg/g,was achieved.Among the monomers,guaiacol and 4-methy-guaiacol were dominant components,and represented 35.38 and 35.52 mg/g,respectively.Proper isolation of lignin before hydrothermal conversion was benefit for the liquefaction reaction.

关 键 词：木质素 亚临界水 催化 解聚 酚类化合物 

分 类 号：TQ35[化学工程]