化学
木质素
产量(工程)
水解
催化作用
羟基值
傅里叶变换红外光谱
有机化学
基质(水族馆)
溶剂
多元醇
核化学
聚氨酯
化学工程
材料科学
工程类
地质学
海洋学
冶金
作者
Nubla Mahmood,Zhongshun Yuan,John A. Schmidt,Chunbao Xu
标识
DOI:10.1016/j.biortech.2013.03.199
摘要
Kraft lignin (KL) was successfully depolymerized into polyols of moderately high hydroxyl number and yield with moderately low weight-average molecular weight (Mw) via direct hydrolysis using NaOH as a catalyst, without any organic solvent/capping agent. The effects of process parameters including reaction temperature, reaction time, NaOH/lignin ratio (w/w) and substrate concentration were investigated and the polyols/depolymerized lignins (DLs) obtained were characterized with GPC-UV, FTIR-ATR, 1H NMR, Elemental & TOC analyzer. The best operating conditions appeared to be at 250 °C, 1 h, and NaOH/lignin ratio ≈0.28 with 20 wt.% substrate concentration, leading to <0.5% solid residues and ∼92% yield of DL (aliphatic-hydroxyl number ≈352 mg KOH/mg and Mw ≈ 3310 g/mole), suitable for replacement of polyols in polyurethane foam synthesis. The overall % carbon recovery under the above best conditions was ∼90%. A higher temperature favored reduced Mw of the polyols while a longer reaction time promoted dehydration/condensation reactions.
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