5-羟甲基糠醛在稀硫酸催化下的降解反应动力学  

Decomposition kinetics of 5-hydroxymethylfurfural catalyzed by dilute sulfuric acid

作　　者：彭新文[1] 吕秀阳[1] 

机构地区：[1]浙江大学二次资源化工国家专业实验室,浙江杭州310027

出　　处：《化工学报》2008年第5期1150-1155,共6页CIESC Journal

基　　金：国家自然科学基金项目(20476089);浙江省自然科学基金项目(Y405157);杭州市科技发展计划项目(20051331B17)~~

摘　　要：5-羟甲基糠醛脱羧生成乙酰丙酸是生物质资源出发制备乙酰丙酸过程中的关键步骤之一。为了研究低硫酸浓度下水解生物质制备乙酰丙酸工艺的可行性,系统地测定了在压力5MPa、初始浓度1～9mg.ml-1、硫酸浓度0.05%～0.4%(质量分数)、温度150～190℃条件下,5-羟甲基糠醛在稀硫酸催化下的降解反应动力学数据,并以主反应生成乙酰丙酸、副反应生成腐黑质的平行反应动力学模型对数据进行了拟合,拟合结果表明,在实验范围内,主、副反应对5-羟甲基糠醛均为一级反应;主反应对H+浓度为1.16级,反应的活化能为78.5kJ.mol-1;副反应对H+浓度为0.722级,反应的活化能为98.0kJ.mol-1。研究结果表明,降低温度和提高硫酸浓度有利于提高生成乙酰丙酸的选择性。The decarboxylation of 5-hydroxymethylfurfural to levulinic acid is a key step in the preparation of levulinic acid from biomass. In order to study the feasibility of producing levulinic acid by hydrolyzing biomass with dilute sulfuric acid, the decomposition kinetics of 5-hydroxymethylfurfural was systematically investigated at initial 5-hydroxymethylfurfural concentration of 1--9 mg · ml ^-1 sulfuric acid concentration of 0.05%--0.4% （mass） and temperature from 150℃ to 190℃. A parallel reaction mechanism was proposed to data reduction, in which the main reaction was to form levulinic acid and the side reaction was to form undesirable humins. With the first-order kinetics equations, the activation energies evaluated were 78.5 kJ · mol ^-1 , 98. 0 kJ · mol^-1 and the reaction orders to H^＋ concentration were 1.16, 0. 722 for main and side reactions respectively under the experimental conditions. The results indicated that the selectivity of levulinic acid could be improved at a lower reaction temperature and a higher sulfuric acid concentration.

关 键 词：5-羟甲基糠醛 乙酰丙酸 稀硫酸 降解 动力学 

分 类 号：TQ032[化学工程] O643.12[理学—物理化学]