稀酸预处理对玉米秸秆中4类非木质素组分的降解规律研究

摘要

Four main non-lignin constituents in corn stover, including cellulose, hemicellulose, hot water extractives, and ethanol extractives, were prepared and pretreated with dilute sulfuric acid, respectively. Their water soluble degradation products profiles were analyzed by high performance liquid chromatography detection. During dilute sulfuric acid pretreatment, glucose, formic acid ( FA ) , levulinic acid ( LA ) , and 5-hydroxymethylfurfural ( HMF ) were released from cellulose degradation. Xylose, arabinose, glucuronic acid, galacturonic acid, acetic acid ( AA) , and furfural were released from hemicellulose degradation. The hot water extractives degradation produced glucose, xylose, arabinose, FA, AA, LA, HMF, and furfural, and only trace of glucose, xylose, AA, LA, and HMF were found in the hydrolyzates of ethanol extractives. Totally, FA, LA, and HMF mainly originated from cellulose degradation at the yields of 1. 4%, 2. 7%, and 2. 2%, while AA and furfural came from hemicellulose degradation at the yields of 3. 1% and 7. 8% on the basis of corn stove weight, respectively. Orthogonal tests showed that the AA production was significantly affected by the concentration of sulfuric acid, while the FA, LA, HMF, and furfural formations were seriously affected by the pretreatment temperature.%分离制取玉米秸秆中非木质素类的4类组分纤维素、半纤维素、热水提取物和乙醇提取物，采用高效液相色谱研究其在稀硫酸预处理过程中主要水溶性降解产物的生成规律。其中，纤维素降解生成葡萄糖、甲酸、乙酰丙酸和5-羟甲基糠醛；半纤维素降解生成木糖、阿拉伯糖、葡萄糖醛酸、半乳糖醛酸、乙酸和糠醛；热水提取物降解生成葡萄糖、木糖、阿拉伯糖、甲酸、乙酸、乙酰丙酸、5-羟甲基糠醛和糠醛；乙醇提取物降解生成少量的葡萄糖、木糖、乙酸、乙酰丙酸和5-羟甲基糠醛。抑制物甲酸、乙酰丙酸和5-羟甲基糠醛主要来自纤维素，乙酸和糠醛来自半纤维素，产量可分别为1.4%、2.7%、2.2%、3.1%和7.8%(以玉米秸秆计)。硫酸质量分数是影响乙酸产量的主要工艺因素，而反应温度是影响甲酸、乙酰丙酸、5-羟甲基糠醛和糠醛产量的主要工艺因素。