Abstract:

2,5-Furandicarboxylic acid (2,5-FDCA) is a monomer of biodegradable plastic polyethylene furanoate and will be in huge demand in the near future. In order to solve the problem of lower yield in the preparation of 2,5-furandicarboxylic acid during cyclodehydration of hexaric acid, higher selective catalytic systems were explored in this paper. HBr-MgBr₂ and HBr-LiBr were found to have excellent catalytic ability for cyclodehydration of hexaric acid. 2,5-FDCA yield of 84.2% was achieved for potassium bisaccharate cyclodehydration catalyzed with 3%(mass)HBr-6%(mass) MgBr₂ at 120℃ and 2 h reaction time. The molar yield of 2,5-FDCA remained above 80% when substrate concentration was up to 5%(mass) and actual water concentration was enriched from 3.3% to 16.5%. The kinetics of cyclodehydration of potassium bisaccharate to 2,5-FDCA at temperatures from 100℃ to 130℃ were measured with 3%(mass) HBr-6%(mass) MgBr₂. The activation energy of 2,5-FDCA formation was 108.9 kJ/mol and that of by-product formation was 136.6 kJ/mol by first-order kinetic fitting. The research work has played a positive role in promoting the industrialization of 2,5-FDCA route by dehydration and cyclization of hexadecanoic acid.

Key words: hexaric acid, 2,5- furandicarboxylic acid, cyclodehydration, catalysis, reaction kinetics

摘要：

2，5-呋喃二甲酸（2，5-FDCA）是生物可降解塑料聚呋喃二甲酸乙二醇酯的聚合单体，未来需求量巨大。针对己糖二酸脱水环合制备2，5-呋喃二甲酸存在的收率低问题，开展了更高选择性催化体系的构建研究，成功筛选到了两个优良的催化体系：HBr-MgBr₂、HBr-LiBr。3%（质量）HBr-6%（质量）MgBr₂催化、120℃下反应2 h，D-葡萄糖二酸单钾盐脱水环合制备2，5-FDCA收率达到84.2%。当反应底物浓度低于5%（质量）以及水含量从3.3%富集到16.5%时，2，5-FDCA的摩尔收率未见明显下降，且都可维持在80%以上。测定了100~130℃温度范围内3%（质量）HBr-6%（质量）MgBr₂催化D-葡萄糖二酸单钾盐脱水环合制备2，5-FDCA动力学数据，采用一级反应动力学拟合得到2，5-FDCA的生成反应活化能为108.9 kJ/mol、副产物生成活化能为136.6 kJ/mol。研究工作对己糖二酸脱水环合制备2，5-FDCA路线的工业化具有积极推动作用。

关键词: 己糖二酸, 2, 5-呋喃二甲酸, 脱水环合, 催化, 反应动力学