研究了在N,N-二甲基甲酰胺(DMF)-离子液体[BMIm]Cl混合溶剂中将蔗糖高效转化为5-羟甲基糠醛(5-HMF)的反应。运用紫外-可见分光光度计对水解液中5-HMF进行定量分析并计算其收率。考察了Cr Cl3·6H2O、Al Cl3·6H2O、Sn Cl4·5H2O、Fe Cl3、Co Cl2·6H2O、Zn Cl2、Cu Cl2·2H2O、Ca Cl2 8种催化剂对反应的催化效果,结果表明Al Cl3·6H2O催化效果最为明显。以Al Cl3·6H2O为催化剂研究了不同反应条件如时间、温度、溶剂中DMF-[BMIm]Cl质量比、催化剂Al Cl3·6H2O的用量对5-HMF收率的影响,得到的最佳条件为以0.5mmol蔗糖为反应物,0.4mmol Al Cl3·6H2O为催化剂,反应时间2h,反应温度120℃,5g质量比为85∶15的DMF-[BMIm]Cl混合溶剂,此条件下5-HMF收率最高可达63.4%。研究表明,DMF-[BMIm]Cl混合溶剂体系对蔗糖转化为5-HMF有一定的促进效果,在此溶剂体系中以Al Cl3·6H2O为催化剂时可以得到较高的5-HMF产率。
A series of experiments were used to study the conversion of sucrose into 5-hydroxymethylfurfural(5-HMF) in DMF-ionic liquid([BMIm]CI) mixed solvent. UV-vis spectrophotometer was used for the quantitative analysis and the yield of 5-HMF calculation. The catalytic efficiencies of the eight metal chlorides(Cr Cl3·6H2O,Al Cl3·6H2O,Sn Cl4·5H2O,Fe Cl3,Co Cl2·6H2O,Zn Cl2,Cu Cl2·2H2O,Ca Cl2) were studied. The results show that catalytic efficiency of Al Cl3·6H2O is the highest. Different reaction conditions,such as time,temperature,quality ratio of DMF-[BMIm]Cl mixed solvent and catalyst dosage were investigated. The optimal condition for the highest 5-HMF yield,63.4%,is determined as follows:0.5mmol sucrose as reactants,0.4mmol Al Cl3?6H2O as catalyst,reaction time 2h,reaction temperature 120℃ in 5g quality ratio of 85∶15 DMF-[BMIm]Cl mixed solvent. Research indicates that DMF-[BMIm]Cl mixed solvent system has certain promoting effect to the conversion of sucrose into 5-HMF,as catalyst Al Cl3·6H2O can get higher 5-HMF yield in the solvent system.