イオン液体（1-メチルイミダゾリウム硫酸水素塩）処理と減圧水蒸気蒸留法を組み合わせたモウソウチク（<i>Phyllostachys edulis</i>）からのフラン化合物生産とイオン液体のリサイクル性能

Abstract

Furan compounds, especially 5-hydroxymethylfurfural (5-HMF) and furfural (FF), are promising platform chemicals that can be produced from various lignocellulosics. This study presents production of the furan compounds from moso bamboo (Phyllostachys edulis) in an ionic liquid, 1-methylimidazolium hydrogen sulfate ([HMIM]HSO4), which acts as both solvent and acid catalyst during the furan compound production. Vacuum steam distillation (VSD) technique, which facilitates simultaneous removal and purification of the furan compounds, was combined to the process. Reaction of the bamboo sample (30 mg) in [HMIM]HSO4 (3.0 g) at 180 o C for 30 min at 20 hPa with continuous steam supply (3.1 mL/min based on liquid water amount) produced 5-HMF and FF in 20.6 and 11.4 wt% yields, which were significantly greater than the maximum yields of those compounds obtained in the experiment without the VSD equipment (5-HMF: 6.6 wt%, FF: 4.6 wt%). The furan compounds were recovered in a cold trap separated from the main reactor as an aqueous solution with significant purity. After 9 times recycling of the ionic liquid without any refreshing treatment of the medium, the yield of the furan compounds decreased by only 10~30 % compared to the initial yield with fresh [HMIM]HSO4. The small decrease in the yield was attributed mainly to the presence of bamboo-derived solid residue piled in [HMIM]HSO4 during the reaction.