In Situ Selective Hydrogenation Of Cinnamaldehyde By Water-gas Shift Over Molybdenum Catalyst

Green chemistry has always been the theme of scientific research and production and life pursuit,which is also the mainstream to achieve sustainable development of resources.Catalytic transfer hydrogenation technology is widely used in industrial production and scientific research because of its advantages of environmental friendliness,high atomic economy,stable product quality and simple operation.There are two main hydrogenation methods of catalytic hydrogenation,which are molecular hydrogen hydrogenation and catalytic transfer hydrogenation.Conventional hydrogenation reaction uses hydrogen as hydrogen source,while catalytic transfer hydrogenation uses polyatomic molecules containing hydrogen as hydrogen source.During the reaction,the hydrogen from the donor is transferred to the substrate.Compared with conventional hydrogenation reaction,catalytic transfer hydrogenation has the advantages of high safety,low reaction temperature,low equipment requirements and high selectivity.As an intermediate step of industrial hydrogen production,water-gas conversion reaction has been widely used in industrial hydrogen production.The water-gas shift reaction converts equal amounts of CO and H₂O into CO₂ and H₂.By means of catalytic transfer hydrogenation,hydrogen produced in situ from water-gas shift reaction can be used as hydrogen source to directly hydrogenateα,β-unsaturated aldehydes to unsaturated alcohols.The specific research contents of this paper include:（1）Molybdenum disulfide catalysts were synthesized by hydrothermal method,and their crystal valence was determined by XRD and XPS,which were used in water gas conversion reaction.Molybdenum disulfide series catalyst loaded active metal Au improve the performance of water gas shift hydrogen production of molybdenum disulfide catalyst.The water-gas shift performance of 1Au@Mo C_x catalyst is better than that of Au supported molybdenum carbide catalyst.（2）Using the idea of catalytic transfer hydrogenation,we coupled the water gas conversion reaction with the selective hydrogenation reaction of cinnamaldehyde.The selective hydrogenation reaction was carried out with water as hydrogen source,low cost carbon monoxide as oxygen acceptor and Au/Mo C as catalyst.The conversion rate of cinnamaldehyde is above 90%and the selectivity of cinnamol is close to 80%at 150℃,which is showing great C=O bond hydrogenation selectivity.Meanwhile,the bulk phase structures and surface valence states of 1Au@Mo C_x、6Au@Mo C_x and 1Au@βMo₂C were characterized by X-ray diffraction,high resolution spherical aberration correction electron microscopy and X-ray photoelectron spectroscopy,which is confirmed that the catalytic activity center of1Au@Mo C_x is the synergy of Au^δ+andαMo C_1-x.The adsorption of C=O double bond of cinnamaldehyde on Au/Mo C was confirmed by diffuse reflectance in-situ infrared spectroscopy and the reaction mechanism was speculated.