竹材纤维定向醇解转化制备乙酰丙酸甲酯的研究

Study on preparation of methyl levulinate by directional alcoholysis of bamboo biomass

  • 摘要: 以固体酸为催化剂、二烷氧基甲烷/低碳醇为复合溶剂,考察竹材中纤维素和半纤维素定向醇解的过程。通过调控反应条件(复合溶剂的组成和配比、固体酸催化剂的种类和用量、反应温度和时间),获得最佳反应条件(复合溶剂二甲氧基甲烷/甲醇质量比为5 g∶15 g,硅钨酸的用量为0.002 mol,120 min,200 ℃)下,竹材的转化率为81.53%,乙酰丙酸甲酯的得率为28.39%。同时,研究多种生物质模型化合物(葡萄糖、木糖、5-羟甲基糠醛、糠醛、戊聚糖和微晶纤维素)的转化过程,结合反应过程中间产物的检测结果,推断竹材中半纤维素、纤维素“一步法”定向醇解制备乙酰丙酸酯的过程。

     

    Abstract: The process of directional alcoholysis of cellulose and hemicellulose in bamboo was investigated using solid acid as catalyst and dialkoxymethane/lower alcohol as co-solvent. By adjusting the reaction conditions (composition and ratio of the co-solvent, the type and amount of solid acid catalyst, reaction temperature and time), the optimal reaction conditions were obtained (dimethoxymethane/methanol with a mass ratio of 5 g/15 g, the solid acid catalyst silicotungstic acid 0.002 mol, reaction time 120 min, and reaction temperature 200 ℃), the conversion of bamboo was 81.53%, and the yield of methyl levulinate was 28.39%. At the same time, the conversion process of a variety of biomass model compounds (xylose, glucose, furfural, 5-hydroxymethyl furfural, pentosan and microcrystalline cellulose) was studied in detail, then the fundamental mechanism of directional alcoholysis conversion of cellulose and hemicellulose to produce methyl levulinate was put forward according to the detection results of intermediate products in the reaction process.

     

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