Method for preparing nickel catalyst supported on SiO2 microspheres and application of nickel catalyst

Abstract

A method for preparing a nickel catalyst supported on SiO2 microspheres comprises the steps of preparing a water-soluble silicon source solution A; preparing an emulsifier B; preparing an aqueous solution C of a nickel salt and an optional additive metal salt; adding the emulsifier B to the solution A, and performing stirring, suction filtration, washing and drying, so as to obtain SiO2 microspheres; and performing post-treatment on the microspheres by using dilute ammonia water, adding the solution C, and performing impregnation, rotary evaporation, microwave drying, roasting and reduction toobtain the nickel catalyst supported on the SiO2 microspheres. When the nickel catalyst is applied to catalytic hydrogenation of dinitrotoluene DNT for preparing toluene diamine TDA, the conversion rate of DNT is 100% and the selectivity of TDA is 99.9%.

Description

Technical field: [0001] The present invention relates to a preparation method and application of a catalyst, in particular to a catalyst loaded on SiO 2 Preparation method of Ni catalyst on microspheres and its application to DNT hydrogenation to prepare TDA. Background technique: [0002] Toluene diamine (TDA) is an intermediate for the preparation of toluene diisocyanate (TDA), and TDA is an important primary product for the preparation of polyurethane (PU), which is widely used in elastomers, foam plastics, coatings, adhesives and fibers, etc. It is one of the most promising synthetic materials at present. TDA synthesis process mainly includes: iron powder reduction method, alkali sulfide reduction method, electrolytic reduction method, catalytic hydrogenation method, etc. Due to the simple process, high product quality and low environmental pollution, the catalytic hydrogenation method has broad development prospects. Catalytic hydrogenation is divided into gas-phase ...

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Problems solved by technology

However, the alloy powder needs to be sieved, and the fine powder cannot be used, resulting in an increase in the cost of the catalyst; NaOH is used during activation, which produces a large amount of lye wastewater, and the post-processing cost is high.

[0007] CN101439285A discloses a catalyst preparation method for catalytic hydrogenation of nitro compounds to prepare corresponding amino compounds. The catalyst prepared by the method has high activity and good selectivity, but needs to add solvent ethanol, and the metal nickel in the catalyst is The loading capacity is as high as 55%, the metal Ni utilization rate is low, and the catalyst cost is high

[0008] CN102274724A discloses a preparation method of a highly active aromatic compound hydrogenation catalyst, which uses graphene as a carrier and Pt as an active component, and its production cost is very high

[0009] Based on the defects in the above-mentioned prior art, it is necessary to seek a new preparation method for dinitrotoluene hydrogenation catalysts, avoiding the use of noble metals or excessive loading (more than 50%), while reducing catalyst costs, Solve the problems such as the need to add solvent and the reaction pressure is too high in the hydrogenation reaction

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