Cu/red Mud In Preparation Of Catalysts And Their Catalytic Properties In Glycerin Hydrogenolysis Reaction Research

To date, major advances have been made in the transesterification of vegetable oil-based fatty acids to biodiesel. The utilization of the relatively large amount of glycerol side product formed in biodiesel manufacture is a major factor in the overall cost effectiveness of the process. In this work, red mud or hydrotalcite supported Cu catalysts were prepared and tested in hydrogenolysis of glycerol to1,2-propanediol. The catalysts were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM), and N2-physisorption. The main contents are shown below:In our previous study, it was found that Cu/Mg(Al)O catalyst after reaction showed XRD patterns characteristic of hydrotalcite, and the interlayer space of catalyst after reaction were affected by reaction conditions. In this work, the formation mechanism of reconstructed hydrotalcite was studied. It was found that the rise of interlayer space was due to the intercalation of reaction product,1,2-propanediol. The desorption of1,2-propanediol was affected by hydrogen pressure. The larger the magnitude of hydrogen pressure, the easier the desorption of1,2-propanediol.Red mud was investigated with a view to determine its viability as a basic catalyst support for use in glycerol hydrogenolysis. In this work, red mud supported Cu catalysts were prepared by deposition precipitation and impregnation methods. The structure and catalytic activity of Cu/red mud was determined. It was found that the activity of Cu/red mud was affected by its structure and preparation method. Deposition precipitation was better than impregnation method. The optimum loading amount of Cu was10%. Effect of reaction conditions was also investigated. Under optimum reaction conditions.9wt.%of catalyst,100%glycerol, hydrogen pressure8MPa, reaction temperature220℃, the conversion of glycerol was92%and1,2-propanediol yield exceeded67%at24h.