Use Composite Oxide Synthesis Of Vanillin

Selective oxidation of vanillin alcohol to vanillin, the process is simple,the raw material is cheep,the route is shout,less demanding on equipment;and high purity and good selectivity of vanillin,it's huge space for research and development of vanillin synthesis in industry.But the catalyst used in the selective oxidation vanillin alcohol show good performance still remain in the noble metal catalysts and some homogeneous transition metal catalysts,it's difficult to meet industry needs.Based on this point,this paper synthesized a series of metal composite oxide heterogeneous catalysts,prepared by precipitation made Co-Fe catalyst system and Co-Sm catalysts system,optimize the best catalyst 5Co3Sm0.25CuxO for alcohol oxidation,and also use it catalyze 4-hydroxy guaiacol oxidation.Use modem analytical methods characterization the Smb-prepared catalysts.Obtained the following results:Co-Fe catalysts system and Co-Sm catalysts system show good selectivity of vanillin,but vanillin alcohol conversion rate are not high;the Cu additions greatly increased level of catalytic activity,and improve the conversion rate of vanillin alcohol,but the selectivity of vanillin are affected by some degree.Add Cu in Co-Fe catalysts system,the selectivity of vanillin alcohol decreased significantly.Add Cu in Co-Sm catalysts system greatly improved catalytic activity and the selectivity of product is decreased slightly.After ten times recycling use the catalyst 5Co3Sm0.25CuxO still performance good selectivity and conversion.It indicated that the catalyst 5Co3Sm0.25CuxO not only has good catalyst performance but also has long use times.Optimize the different reaction factors by the catalyst 5Co3Sm0.25CuxO,obtain the best process:reaction temperature:100℃, time:4h,Oxygen pressure:0.3MPa, the conversion of vanillin alcohol:91.6%, the selectivity of vanillin:92.1%, the yield of vanillin:84.4%; the conversion of 4-hydroxy guaiacol:>99%, the selectivity of product:81.8%, the yield:81.8%. Application the BET,ICP,TG/DTA,XRD,TPR etc. analyzes catalytic activity of Smb-prepared catalysts,optimization of the catalyst-assisted selection.The catalyst 5Co3Sm0.25CuxO not only showed good catalytic performance for the oxidation of vanillin alcohol and 4-hydroxy guaiacol,but also the press of catalyst preparation is simple,low cost,after simple centrifugation the catalyst can be recycling,together the long use time,we can see a strong application prospects in the oxidation of vanillin alcohol and 4-methyl guaiacol.