Characterization Analysis And Catalytic Performance Of Hydrotalcite Of Supported Pt-based Catalysts

In the chemical field,cinnamaldehyde?CMA?is a commonly used?,?-unsaturated aldehyde,and its hydrogenated products,cinnamyl alcohol?CMO?and phenylpropionaldehyde?HCMA?,are widely used in medicine and fragrance.During the experiment,C=O has higher thermodynamic stability and is less prone to hydrogenation than C=C.The hydrogenation reaction is not easy due to high thermodynamic stability.Therefore,how to obtain high-performance catalysts becomes a difficult problem to be solved in the cinnamaldehyde hydrogenation process and it is also the key issue of this paper.The effect of supported Pt-based catalysts on the catalytic performance of selective hydrogenation of cinnamaldehyde was investigated.The Pt-based catalysts were prepared by using hydrotalcite?LDHs?as the carrier and Pt as the main active component.Based on the innovation of the carrier,LDH carriers with different morphologies were prepared.The catalysts were characterized by XRD,SEM,FT-IR and XPS.The relationship between preparation method,structure,physicochemical properties and catalytic activity was studied.The main conclusions of this theory are as follows:?1?A series of hydrotalcite?LDHs?carriers were synthesized by one-step precipitation method and hydrothermal method.Based on the crystallization time and the change of templating agent,the controllable preparation of LDHs grain size and morphology was realized.It is obtained that as the crystallization temperature increases,the size of the LDH increases.The layered anion intercalation structure was successfully prepared,which proved that the LDHs anionic layered material has strong lamination flexibility.Pt was used as a catalyst in LDHs as a catalyst and applied to the catalytic hydrogenation of cinnamaldehyde.The catalyst Pt/LDH2exhibited good catalytic performance.?2?Pt/LDH-x catalysts were synthesized by equal volume impregnation method and the effects of its active components and LDHs on the hydrogenation of cinnamaldehyde were analyzed.The effects of multi-factors on catalytic hydrogenation and catalyst recycling were also investigated.The results showed that Pt/LDH-1 had a good activity after reduction at 300°C H2.After H₂ pressure of 1 MPa and reaction at 40°C for 2 h,the conversion of cinnamaldehyde?CMA?was 79.8%.Cinnamyl alcohol?CMO?The selectivity is 82.1%.After 5 cycles,it has maintained good stability and achieved stable and effective utilization of the metallic catalysts.