Preparation Of The Acidic Catalyst Based On NZP Compound

CaZr4(PO4)6was synthesized by sol-gel method method and doped with different aluminum sources areas in this paper. Then catalytic activity of CaZr4(PO4)6samples by using a-pinene isomerization as probe reaction, meanwhile, the sample compared with the CZP by coprecipitation method and modified, it illustrate that the different preparation methods effect on the physical properties of the sample and its catalytic activity. The phases, pore structure and doping amount of Al of the samples were characterized by X-ray diffraction (XRD), N2adsorption and X-ray fluorescence (XRF). The results showed that:(1) The effects of doping modification of Al(NO3)3, AlCl3, and Al2(SO4)3on the acid catalysis activity of CZP are studied. With the conditions of150℃,4hours of reacting time, and the ratio of a-pinene and catalyst in mass of10:1, it shows by the probe reaction that the catalytic activity of CaZr4(PO4)6synthesized by doping Al(NO3)3is higher than A12(SO4)3and AlCl3.(2) CZP made by sol-gel method has been modified by phosphotungstic acid. With the feed ratio of a-pinene and the catalyst is10:1(in mass), the reation time is4hours, and the temperature is150℃, it shows that the a-pinene conversion rate is range from20.79%to97.29%, the conversion rate of a-pinene reached to95%in the condition HPW-CZP-5and HPW-CZP-20. So the appropriate HPW load is5%.(3) The acid catalysis activity of Al-CZP-n made by sol-gel method is higher than that made by coprecipitation method. The results of XRD show that, the sample of Al-CZP-n made by sol-gel method is amorphous state under the calcination of750℃, while the sample of Al-CZP-0.1made by coprecipitation method has complete crystallization under the calcination of700℃.The difference of crystallinity of the samples prepared by two methods maybe one of factors to influence the catalytic activity.(4) From the comparison of the catalytic activity of the HPW-CZP-5made by sol-gel method and coprecipitation method, we find that the catalytic activity of HPW-CZP-5made by sol-gel method is higher than that made by coprecipitation method. The a-pinene conversion rate of the former is97.87%while the latter is only 75.46%under the same conditions. The difference of porous structure of HPW-CZP-5prepared by two methods maybe another one of factors to influence the catalytic activity.