Study On Efficient Catalytic Hydrogenation Of Cinnamaldehyde By Porous Amorphous Alloy

Amorphous alloys have attracted widespread attention due to the excellent catalytic activity,good selectivity and strong sulfur-poison resistance,Moreover,the simply synthetic procedure with less pollution is in accord with the development trend of green chemistry.Amorphous alloy has a great application potential in the selective hydrogenation of unsaturated carbonyl compounds.However,the low surface area of amorphous alloy synthesized by traditional chemical reduction seriously hinders their practical application in industry.In this thesis,a porous amorphous alloy with a high surface area was successfully preparated,and the selective hydrogenation of cinnamaldehyde was investigated in detail.The main research works were described as follows:(1)The porous Co-B and Co-M-B(M=Fe,Zn,Mo,Sn,W and Cr,etc)amorphous alloys were prepared by using Ca CO₃ in situ generated with co-precipitation and bubble originated from the in situ reduction reaction as hard template and soft template,respectively,and were used to catalytize the reaction of selective hydrogenation of cinnamaldehyde.The results show that the size and surface roughness of the obtained amorphous alloy spheres can be regulated by the amount of template.The mesoporous hollow spheres with roughsurface and high surface area were synthesized with a third component of 20 wt%Fe,and the specific surface area is 278.8 m²/g.Under optimal reaction conditions:reaction temperature 130?,3 MPa H₂,reaction time 2 h.The conversion of cinnamaldehyde is close to 100%and the selectivity of cinnamyl alcohol is93.4%,and the catalytic activity without evident change after recyle five times.In addition,the possible formation mechanism of porous amorphous alloy materials is proposed in the paper.(2)Base on the results of above mentioned,the fourth component of Zn was introduced into the synthesis system to further improve the performance.The obtained porous quaternary amorphous alloy displayed an enhanced catalytic performance.The results suggested that the improved catalytic performance was ascribed to the high specific surface area and hydrogen adsorption capacity,the synergistic effect between Zn and Fe and the increased number of active centers by the mutual transfer of electrons,and the improved dispersion,disorder and thermal stability of the amorphous alloy resulted by the addition of Zn.Under the optimal reaction conditions:reaction temperature 130?,2 MPa H₂,reaction time 1 h.The conversion of cinnamaldehyde and the selectivity of cinnamyl alcohol are 97.7%and 100%.After recycle 5 times,the catalytic activity did not dislay evident decrease.Moreover,due to the magnetic property of the material,the catalyst can be separated from the reaction liquid phase system rapidly after applying external magnetic field.