Preparation Of Nickel Catalysts And The Performance In Phenol Hydrogenation Reaction

Phenol, as the byproduct of the petrochemical and coal industry, its production isgradually increasing, and the hydrogenation products cyclohexanol and cyclohexanone areimportant materials in chemical industry, In a word, the study of phenol hydrogenationreaction and the preparation of catalysts have the important chemical application value.Nickel-based catalysts have different activity with different reduction methods, each ofthe way has advantages and disadvantages. This paper studied the nickel-based catalystsobtained by different reduction methods, and catalytic performance on phenol hydrogenation.Firstly, the catalysts obtained by hydrogen reduction were studied, including thecharacterization of catalysts and the evaluation of phenol hydrogenation reaction. This chapterstudied the supported catalyst by isometric impregnation method., and investigated manyfactors affecting the catalytic activity, including the nickel source, loading, supports,alkalinity, additives. Beyond that, the process conditions of phenol hydrogenation were alsostudied. It was showed that NiNO3as the nickel source was the best choice, and SiO2as thesupport exhibited higher performance. Alkaline improved the conversion rate of phenol, andincreased the selectivity of cyclohexanone. and the hydrogenation rate was greatly increasedusing cyclohexane as solvent.Secondly, using NaBH4as the reduing agent prepared a series of nickel-based catalysts,and reviewed its hydrogenation activity, the chapter discussed factors affecting the catalyticactivity, for instance, source of nickel, carrier, loading, molar ratio of B/Ni. The resultsshowed that the NiCl2as the source, Al2O3as the carrier was the best choice for thehydrogenation activity, Beyond that, the catalyst with B/Ni was3has the best hydrogenationactivity. Compared with the former two methods, this paper put forward preparing catalyst byusing zinc powder as the reducing agent, and discussed the factors affecting hydrogenationactivity. To improve the utilization rate of nickel, added the supports into system, andexamined phenol hydrogenation activity with supported catalyst obtained by the adsorption ofsupport. This paper put forward using microemulsion system proving the water-in-oil typemicro reactor to prepare supported catalyst which had higher hydrogenation activity andhigher degree of dispersion of Ni, used this catalyst for phenol hydrogenation and discussedits lifetime. The results showed that the utilization rate of Ni was improved with the joining ofsupport, and the degree of dispersion of Ni was enhanced by using the microemulsion system,and then, the activity was improved.