The cleavage of the etheric CO bond in diphenyl ether (DPE), phenethyl phenyl ether (PPE) and benzyl-phenyl ether (BPE) has been investigated by using Ru/C (5% wt) and Pd/C (5% wt), as heterogeneous catalysts, under reaction conditions generally adopted for the reductive catalytic fractionalization of lignocellulosic biomasses (lignin-first approach). Catalytic tests were carried out in the presence of simple C1-C3 alcoholic H-donor solvents (methanol, ethanol and 2-propanol) used as such or in mixture with water in the temperature range of 120–240 °C both in the presence or in the absence of molecular hydrogen as reducing agent. Under transfer hydrogenolysis conditions, the Ru/C catalyst was found to be the best performing system in the cleavage of the 4–O–5 etheric CO bond (95 % DPE conversion in 2-propanol at 210 °C after 3 h of reaction) with a less pronounced tendency in hydrogenating the aromatic ring. Upon increasing the water content in the reaction medium, a decrease in the cleavage of the CO bond of DPE together with a higher production of phenolics is observed as a consequence of the reductive hydrolysis reaction occurrence. The best yield in aromatic compounds (52 %) was obtained by using as solvent a water/2-propanol (75:25, v/v) mixture in absence of added molecular hydrogen, with the alcoholic fraction being the in-situ H-source. A lower tendency to undergo to hydrolysis reaction together with a higher production of aromatics is registered in the case of phenethyl phenyl ether and benzyl-phenyl ether. Results are explained in terms of the higher steric hindrance of PPE and BPE with respect to DPE and of the competitive adsorption of arenes arising from hydrogenolysis of etheric β–O–4 and α–O–4 bonds (phenol + ethyl benzene or phenol + toluene) on the Ru/C catalyst surface.

通过使用Ru / C（5％wt）和Pd / C（5％wt）研究了二苯基醚（DPE），苯乙基苯基醚（PPE）和苄基苯基醚（BPE）中醚C O键的裂解）作为非均相催化剂，在通常用于木质纤维素生物质的还原催化分馏的反应条件下（木质素优先方法）。催化测试是在简单的C1-C3醇氢供体溶剂（甲醇，乙醇和2-丙醇）的存在下或与水在120-240°C的温度下混合存在或进行的情况下进行的在没有分子氢作为还原剂的情况下。在转移氢解条件下，Ru / C催化剂被认为是裂解4–O–5醚C的最佳系统。O键（反应3小时后，在210°C下2-丙醇中95％的DPE转化率）具有较不明显的氢化芳环趋势。随着反应介质中水含量的增加，C的裂解降低由于发生还原水解反应，观察到DPE的O键和更高的酚类产量。在不添加分子氢的情况下，通过使用水/ 2-丙醇（75:25，v / v）的混合物作为溶剂，可获得芳烃化合物的最佳收率（52％），其中醇级分为原位H-资源。在苯乙基苯基醚和苄基苯基醚的情况下，发生水解反应的趋势较低，而芳烃的产生较高。解释结果时，相对于DPE，PPE和BPE的位阻更高，并且由于醚化β–O–4和α–O–4键（苯酚+乙苯或苯酚+甲苯）。