Synthesis of 5-hydroxymethylfurfural (5-HMF) from fructose over cation exchange resin in a continuous flow reactor

A continuous packed-bed reactor was applied for the synthesis of 5-HMF via dehydration of fructose. Cation exchange rasin functionalized with sulfonic acid groups; -HSO3 was used as catalyst. 1-methyl-2-pyrrolidinone (NMP) was used as aqueous solvent to partially substitute water. A biphasic system with methyl isobutyl ketone (MIBK) as organic solvent was applied to enhance the transfer of 5-HMF from aqueous phase. Effects of reaction temperature (90-120 degrees C), residence time (10-60 min), water content in the aqueous phase (30-100 %wt.), and organic-to-aqueous ratio (1:1-4:1) on the conversion of fructose, %yield and selectivity of 5-HMF, and extraction ratio were investigated. High yield of 5-HMF was obtained with increasing reaction temperature or reaction time. Adding NMP enhanced the fructose conversion and selectivity toward 5-HMF to 91.67% and 99.76% at 120 degrees C, residence time of 30 min, NMP-to-water ratio of 7:3, and organic-to-aqueous ratio of 4:1, while the extraction ratio was 81.83%.