Lignin Liquefaction in Supercritical Water
Lignin Liquefaction in Supercritical Water
复制标题
超临界水中的木质素液化
DOI：
10.1007/978-94-009-2737-7_37
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
R. Baldwin
中科院分区：
文献类型：
--
作者：
D. K. Johnson;H. Chum;R. Anzick;R. Baldwin
从白杨木的水性甲醇有机溶剂制浆中获得的两种木质素在悬浮于水中并加热到略高于水的临界温度时被液化。在钯碳催化剂和低氢分压(730 psi)存在下，在搅拌高压釜中进行液化。将含水木质素悬浮液注入预热的高压釜中可以研究反应时间的影响，从而最大限度地减少加热时间的影响。木质素以良好的收率转化为棕色粘稠油，可溶于乙酸乙酯。其他产品包括乙酸乙酯不溶部分 (~10%) 和含碳气体 (~10%)，例如一氧化碳、二氧化碳、甲烷、乙烷等。5-20 分钟后获得最高的油收率（~70%）。 45 分钟后，随着气体形成的增加，油产量下降。液化木质素的表观分子量分布比起始木质素小 2-3 倍，表明已发生大量解聚。油的挥发性部分含有丁香酚、愈创木酚、儿茶酚和苯酚。增加反应时间将丁香酚和愈创木酚转化为儿茶酚。
Two lignins obtained from aqueous methanol organosolv pulping of aspen wood have been liquefied when suspended in water and heated to slightly above the critical temperature of water. Liquefaction was carried out in a stirred autoclave in the presence of a palladium on carbon catalyst and a low partial pressure of hydrogen (730 psi). Injection of the aqueous lignin suspensions into a pre-heated autoclave permitted study of reaction time effects minimizing the effect of heat-up time. The lignins were converted in good yield to brown viscous oils, that were soluble in ethyl acetate. Other products included an ethyl acetate insoluble fraction (~10%) and carbon-containing gases (~10%), e.g. carbon monoxide, carbon dioxide, methane, ethane, etc. The highest yields (~70%) of oil were obtained after 5–20 minutes. Yields of oil decreased after 45 minutes with increasing formation of gases. The apparent molecular-weight distributions of the liquefied lignins were 2–3 fold smaller than the starting lignins, indicating substantial depolymerization had taken place. The volatile fraction of the oils contained syringols, guaiacols, catechols and phenol. Increasing reaction time converted syringols and guaiacols into catechols.