Preparation And Catalytical Application Of CuCr-HTLcs And NiAl-HTLcs/ZSM-5 Composite

Hydrotalcite-like compounds (HTLcs) are a kind of pillared clay materials and shown highly activiy and selectivity in catalytic reaction because of their special composition and structure. However, the application of the HTLcs have been limited because of fewer species and higher impurity. Therefore, it is widely studied to synthesize and development novel HTLcs.For many years, benzoin ether derivatives have been well known as efficient UV radical photoinitiators, Which have found extensive applications in the industries of coating, plastics, printing and electronic.In this paper, CuCr-HTLcs and NiAl-HTLcs/ZSM-5 composite were synthesized by coprecipitation method with variable pH value. Then the effect of different factors on phase was studied in details and their physicochemical properties were characterized. The catalytic activities of CuCr-HTLcs were investigated in the synthetic reaction of benzoin methyl ether with methanol and phenylalhyde, while the catalytic activities of composite were introduced into the synthetic reaction of benzoin ethyl ether with ethanol and phenylalhyde.During the synthesis process, with Cu(NO3)2 and Cr(NO3) 3 salt as the materials, NaOH and Na2CO3 solution as the precipitator. After that, effects of different factors on the phase of prepared CuCr-HTLcs was studied such as the cations ratio in the materials, hydrothermal treatment temperature and time, calcined temperatures. The results of the preparation of CuCr-HTLcs shows that nCu/nCr=2.0 in the materials with pH=4.3±0.2 and hydrothermal treatment at 110℃for 6h; With the increase of Cu2+, specific surface area and pore volume decrease, the average pore size has been increase, the pore size distribution concentrated when nCu/nCr=2.0. In order to study the catalytical acitivities of CuCr-HTLcs, they are introduced into the synthetic reaction of benzoin methyl ether. The catalytical result shows that the catalysts have the catalytical activities of cyanide or VB1 salt because of special structure and properties. Besides, they are superior to catalysis the synthetic reaction of benzoin with no pollution and low cost. The key of successfully catalytical reaction is that the synergic effect between acidity and basicity and the pillar structure exists. Effects of different influenced factors on the reaction such as the reactant ratios, temperature, catalyst dosage, composition and structure of the catslyst were investigated in details, and then the reaction mechanism was set forth by the calculation of kinetics parameters. The result of the synthetic reaction of benzoin methyl ether shows that CuCr-HTLcs could be used as an excellent catalyst in the reaction, in which the conversion of phenylalhyde was 89.56% and the selectivity of benzoin methyl ether was nearly 100% underthe optimal condition. This reaction was kind of one progression reaction and the reaction activity energy was 15.795KJ/mol.During the synthesis process, with and Ni(NO3)2, A1(NO3) 3 salt and ZSM-5 zeolite as the materials, NaOH and Na2CO3 solution as the precipitator. After that, effects of different factors on the phase of prepared composite was studied such as the cations ratio in the mater-ials, hydrothermal treatment temperature and time, calcined temperatures. The results of the preparation of composite could be successfully prepared when m(NiAl-HTLcs)/m(ZSM-5)= 1.0 with pH=5.3～5.7 and hydrothermal treatment at 110℃for 3h. The XRD, FTIR and SEM show that the ZSM-5 zeolite phase in the composite was covered by a rough layer of NiAl-HTLcs. With the BET method the large surface area of composite than NiAl-HTLcs, ease the aggregation. In order to study the catalytical acitivities of NiAl-HTLcs/ZSM-5 composite, they are introduced into the synthetic reaction of benzoin ethyl ether. The result of the synthetic reaction of benzoin ethyl ether shows that composite could be used as an excellent catalyst, in which the conversion of phenylalhyde was 56.54%and the selectivity of benzoin ethyl ether was nearly 100% under the optimal condition. The composite-could be recycled for many times with high catalytic acitivity. This reaction was kind of one progression reaction and the reaction acitivity emergy was 10.449 KJ/mol.