5-hydroxymethylfurfural (HMF), accessible from various feedstocks, represents an important renewable platform-chemical, precursor for valuable biofuels and bio-based chemicals. In this work, the continuous hydrogenation of an aqueous solution of HMF to give strategic monomers, 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) was investigated in a continuous flow reactor adopting a commercial Ru/C (5 wt%) as catalyst. The influence of the main process variables on products yield and selectivity was studied and optimized. The highest BHMF and BHMTHF yields of 87.9 and 93.7 mol%, respectively, were achieved by tuning the catalyst contact time, keeping all other variables constant (temperature, pressure, hydrogen flow rate, initial HMF concentration). Intraparticle diffusion limitation for hydrogen and HMF was shown to occur at some of the tested conditions by performing the HMF hydrogenation with different catalyst particle sizes, confirmed by calculations. Constant catalyst activity was observed up to 6 h time-on-stream and then gradually reduced. Fresh and spent catalyst characterization showed no significant sintering and negligible leaching of ruthenium during time-on-stream. A decrease of the specific surface area was observed, mainly due to humin deposition which is likely the reason for catalyst deactivation. Catalyst performance could be restored to initial values by a thorough washing of the catalyst.

5-羟甲基糠醛 (HMF) 可从各种原料中获得，是一种重要的可再生平台化学品，是有价值的生物燃料和生物基化学品的前体。在这项工作中，在连续流动反应器中研究了 HMF 水溶液的连续氢化以得到战略单体 2,5-双（羟甲基）呋喃（BHMF）和 2,5-双（羟甲基）四氢呋喃（BHMTHF）采用商业化的 Ru/C (5  wt%) 作为催化剂。研究并优化了主要工艺变量对产品收率和选择性的影响。最高的 BHMF 和 BHMTHF 收益率为 87.9 和 93.7 mol% 分别是通过调整催化剂接触时间来实现的，保持所有其他变量不变（温度、压力、氢气流速、初始 HMF 浓度）。通过使用不同的催化剂粒径进行 HMF 氢化，表明在某些测试条件下会发生氢和 HMF 的粒子内扩散限制，这通过计算得到证实。观察到恒定的催化剂活性高达 6 h 直播时间，然后逐渐减少。新鲜和用过的催化剂表征表明，在运行期间没有明显的烧结和可忽略的钌浸出。观察到比表面积减少，主要是由于腐殖质沉积，这可能是催化剂失活的原因。通过彻底清洗催化剂，催化剂性能可以恢复到初始值。