Production of 5-hydroxymethylfurfural from Japanese cedar (Cryptomeria japonica) in an ionic liquid, 1-methylimidazolium hydrogen sulfate

Production of 5-hydroxymethylfurfural (5-HMF) from Japanese cedar (Cryptomeria japonica) using an ionic liquid, 1-methylimidazolium hydrogen sulfate ([MIM]HSO(4)), was investigated. 5-HMF can be produced from C. japonica at temperatures above 120 °C. The maximum yield of 5-HMF was about 9 wt% after 15 min of treatment at 160 °C. However, 5-HMF produced in this process tended to decompose as the treatment continued. To avoid decomposition and to provide a means of recovering 5-HMF from [MIM]HSO(4), three reaction systems based on [MIM]HSO(4) were investigated: biphasic [MIM]HSO(4)/organic solvent system, [MIM]HSO(4) with vacuum distillation, and [MIM]HSO(4) with vacuum steam distillation. The [MIM]HSO(4) reaction system combined with vacuum steam distillation was most effective. The maximum yield of 5-HMF was 17.5 wt% after treatment for 45 min at 160 °C. The combination of [MIM]HSO(4) treatment with vacuum steam distillation is suitable for 5-HMF production because it is a one-pot process without the need for catalysts or pretreatment.