采用羟基磷灰石和镁铝水滑石两种固体碱为载体制备了Ru催化剂,通过N2物理吸附、扫描电子显微镜、高分辨透射显微镜、X射线衍射分析表征了形貌和物理化学性能,并与纳米碳纤维负载的Ru催化剂(Ru/CNFs)在无碱促进剂及有碱促进剂存在下催化山梨醇氢解制备二元醇的活性进行了比较。结果表明,固体碱负载的Ru催化剂,在无碱促进剂的条件下在山梨醇氢解中均表现出与Ru/CNFs相当的催化活性。其中镁铝水滑石负载的Ru催化剂在优化的制备条件下,其催化活性优于加入碱促进剂的Ru/CNFs催化体系,乙二醇和丙二醇等目标产物选择性更高,副产物减少,同时还免除了碱助剂的后续分离和回收,具有良好的应用前景。
Hydrogenolysis ofbiomass-derived sorbitol into ethylene and propylene glycols, an alternative route for petroleum based process, usually takes place over metal catalyst with a base promoter. The presence of soluble bases introduces additional problems for their separation and recovery, increasing the complexity and operating cost of the process. Sometimes, these base additives result in the formation of more side-products. Ru supported on various solid bases to facilitate catalyst recovery and recycle was investigated. Ru catalysts supported on 2 solid bases, hydrotalcite (HT) and hydroxyapatite, were prepared and investigated for sorbitol hydrogenolysis activity in base-free aqueous solution, and their performance was compared with that of Ru catalyst supported on carbon nanofibers (Ru/CNFs), with and without promotion by CaO. The physico-chemical properties of both supports and the supported Ru catalysts were characterized by SEM, N2 physisorption, XRD, TEM and CO2-TPD. The results indicate that Ru particles well disperse on the basic support and show as good activity as Ru/CNFs catalysts in sorbitol hydrogenolysis. The Ru catalyst using HT calcined at 500℃ as a support shows the best catalytic performance with promoted sorbitol conversion, higher selectivity to desired glycols and fewer byproducts. As a result, Ru/HT is believed to be a promising catalyst for sorbitol hydrogenolysis without added base. This is relevant to the development of a green process to produce glycols from biomass.