This study investigates the production of furfural via formic acid-catalyzed dehydration of xylose and the effect of simultaneous extraction of furfural using supercritical carbon dioxide (Sc-CO). The addition of Sc-CO results in a secondary reaction pathway comprised of two steps: CO-catalyzed isomerization of xylose into the reactive intermediate xylulose, followed by furfural production from xylulose, catalyzed by formic acid. Xylose dehydration with CO in both batch and semi-batch systems yielded a higher furfural yield and selectivity compared with systems without CO. The Sc-CO extraction in a semi-batch system prevents furfural degradation by maintaining high productivity, even with increased initial xylose concentration. A maximum furfural yield of 68.5% (71.4% selectivity and 99% separation efficiency) was achieved after 5 h at 140 °C and 20 MPa with a constant flow rate of 5 g/min of CO and initial concentrations of 10 g/L of xylose and 10 wt% of formic acid.

中文翻译：

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使用甲酸作为催化剂从木糖中高效生产糠醛的集成超临界二氧化碳萃取

本研究研究了通过甲酸催化木糖脱水生产糠醛以及使用超临界二氧化碳 (Sc-CO) 同时萃取糠醛的效果。添加 Sc-CO 会产生由两个步骤组成的二级反应途径：木糖在 CO 催化下异构化为活性中间体木酮糖，然后在甲酸催化下由木酮糖生成糠醛。与不使用 CO 的系统相比，在间歇式和半间歇式系统中用 CO 进行木糖脱水可产生更高的糠醛收率和选择性。半间歇式系统中的 Sc-CO 萃取可通过保持高生产率来防止糠醛降解，即使初始木糖浓度增加也是如此。在 140 °C 和 20 MPa 的条件下，在 CO 流量恒定为 5 g/min，初始浓度为 10 g/L 的条件下，5 小时后，糠醛收率达到 68.5%（选择性为 71.4%，分离效率为 99%）。木糖和10wt%的甲酸。