醇/水体系中混酸催化葡萄糖醇解制备乙酰丙酸甲酯  

Synthesis of Methyl Levulinate by Glucose Alcoholysis Catalyzed by Mixed Acid in Alcohol/Water System

作　　者：吴媛 王子华 常春[1,2] 李攀 徐桂转[3] WU Yuan;WANG Zihua;CHANG Chun;LI Pan;XU Guizhuan(School of Chemical Engineering,Zhengzhou University,Zhengzhou 450001,China;Henan Outstanding Foreign Scientists’ Workroom,Zhengzhou 450001,China;College of Mechanical and Electrical Engineering,Henan Agricultural University,Zhengzhou 450002,China)

机构地区：[1]郑州大学化工学院,河南郑州450001 [2]河南省杰出外籍科学家工作室,河南郑州450001 [3]河南农业大学机电工程学院,河南郑州450002

出　　处：《林产化学与工业》2021年第2期39-46,共8页Chemistry and Industry of Forest Products

基　　金：国家自然科学基金资助项目(U1904122);河南省杰出外籍科学家工作室生物质资源加工与高效利用(GZS2018004)。

摘　　要：以超低酸与硫酸盐为混酸催化剂,研究了葡萄糖在甲醇/水体系中醇解制备乙酰丙酸甲酯(ML)的反应过程。在硫酸盐(Al_(2)(SO_(4))_(3)、CuSO_(4)、Fe_(2)(SO_(4))_(3)、Ti(SO_(4))_(2)、SnSO_(4)、ZnSO_(4)、NiSO_(4)、Cr_(2)(SO_(4))_(3))中,Al_(2)(SO_(4))_(3)与超低酸H_(2)SO_(4)的混酸具有良好的催化性能。以混酸作催化剂,考察了葡萄糖初始质量浓度(10~40 g/L)、Al_(2)(SO_(4))_(3)的用量(0.12~0.48 g)、反应温度(160~200℃)以及反应时间(2~6 h)对产物生成的影响规律。在甲醇/水(体积比50/50)的溶剂体系下,原料质量浓度20 g/L、反应时间4 h、反应温度170℃、Al_(2)(SO_(4))3质量0.24 g,0.02 mL H_(2)SO_(4)(0.01 mol/L)的条件下,乙酰丙酸甲酯的最高产率为46.68%,此时乙酰丙酸(LA)产率为24.20%。葡萄糖经醇解首先生成甲基葡萄糖苷(MLG),继而转化为5-甲氧甲基糠醛(MMF),最终转化生成ML。Al_(2)(SO_(4))_(3)催化剂经5次循环使用后仍具有较高的催化活性(ML产率45.92%,LA产率20.58%)。Methyl levulinate(ML)was prepared by the alcoholysis of glucose in a methanol/water system over mixed acid catalysts comprising extremely low acid and metal sulfates.Al_(2)(SO_(4))_(3) with ultralow sulfuric acid showed the highest catalytic performance among the studied metal sulfates(Al_(2)(SO_(4))_(3),CuSO_(4),Fe_(2)(SO_(4))_(3),Ti(SO_(4))_(2),SnSO_(4),ZnSO4,NiSO_(4),and Cr_(2)(SO_(4))_(3)).Moreover,the effects of initial mass concentration of glucose(10-40 g/L),Al_(2)(SO_(4))_(3) mass in mixed acid catalyst(0.12-0.48 g),reaction temperature(160-200℃),and reaction time(2-6 h)on product formation were investigated.The highest yield(46.68%)of ML was obtained in methyl/water(50/50)solvent system with a raw material mass concentration of 20 g/L,0.02 mL H2SO4(0.01 mol/L),and 0.24 g Al_(2)(SO_(4))_(3) at 170℃after 4 h;under these conditions,the yield of levulinic acid(LA)was 24.20%.During the alcoholysis process,glucose was first converted to methyl glucoside(MLG),then methoxymethylfurfural(MMF),and ultimately to ML.Al_(2)(SO_(4))_(3) could be reused at least five times with a slight decrease in catalytic activity(45.92%yield of ML and 20.58%yield of LA).

关 键 词：葡萄糖 硫酸铝 乙酰丙酸甲酯 醇解 

分 类 号：TQ35[化学工程]