Three Of The Ni-based Catalysis Of Dinitrotoluene Liquid Catalytic Hydrogenation

Polyurethane (PU) is a promising composite material, polyurethane material widely used in different medical, food, construction industry and other fields, its application has become the first synthetic materials.Diaminotoluene (TDA) is main raw material for the synthesis of toluene diisocyanate (TDI), toluene diisocyanate (TDI) is an important organic intermediate of synthesis of polyurethane (PU).In this paper, the synthesis of dinitrotoluene (DNT) liquid phase hydrogenation Diaminotoluene (TDA) the preparation of the catalyst and process research.In dinitrotoluene liquid phase hydrogenation synthesize toluene diamine in the study, with the modified skeletal Ni Ni-Fe-Cr-Al catalyst, paint the nickel catalyst and Ni-Mo-B amorphous catalyst in synthesis of dinitrotoluene liquid phase hydrogenation toluene diamine and it is the performance of the reaction were studied, through XRD, DSC and H2-TPD technology to explore the relationship between microstructure and its hydrogenation activity catalyst. Conclusions are as follows:(1) In quenched the preparation of Ni-Fe-Cr-Al alloy as the precursor, aqueous NaOH activation of quenching cold after modified skeletal Ni Ni-Fe-Cr-Al catalyst used in dinitrotoluene preparation diaminotoluene liquid-phase catalytic hydrogenation reaction. Results show that Ni-Fe-Cr-Al alloy powders in an agent for 16 wt% NaOH concentration and NaOH/Al (= 2) preparation of modified skeletal Ni Ni-Fe-Cr-Al is a high efficient catalyst. And methanol as solvent, the amount of DNT for the 5 g, catalyst dosage is 0.5 g (wet weight), reaction temperature 100℃, pressure 2 mpa,120 min, the TDA selectivity and DNT conversion rate are 100%. And modified skeletal Ni Ni-Fe-Cr-Al catalyst using 48 consecutive, the DNT conversion and TDA selectivity are above 97%.(2) The paint U-Ni-A nickel catalyst is through the adoption of zinc powder reduction preparation of nickel chloride, applied to the preparation DNT liquid phase catalytic hydrogenation. Results showed that the preparation temperature, amount of expansion agent and zinc powder for paint the original nickel U-Ni-A large effect on catalyst activity. And methanol as solvent, the amount of DNT for the 5 g, catalyst dosage is 0.5 g (wet weight), reaction temperature 100℃, pressure 2 mpa,120 min, the DNT conversion and TDA selectivity rate of 99.77% to 97.23%. And the U-Ni-A nickel catalyst using 7 consecutive,the DNT conversion rate is 70.61% and TDA selectivity is 80.3%.(3) Start from the basic preparation conditions of catalysts, examines the n (KBH4)/n (Ni) than amorphous Ni-B DNT hydrogenation activity of the catalysts. Results show that KBH4/Ni catalyst activity and selectivity are 4, and methanol as solvent, the amount of DNT for the 5 g, catalyst dosage is 0.5 g (wet weight),reaction temperature 100℃, pressure 2 mpa,120 min, the DNT conversion rate of 95.4%.(4) Assistant Mo, Co, and La on amorphous Ni-B catalyst structure and its application applied to the preparation DNT liquid phase catalytic hydrogenation. And through XRD, DSC, H2-TPD technology to explore the relationship between microstructure and its hydrogenation activity catalys. Results show that compared with Ni-B amorphous catalyst, catalyst Ni-Mo-B better thermal stability, adsorption of H2, the TDA in DNT hydrogenation catalyzed synthesis reaction, the catalyst performance is better. When the addition amount of Mo content of 6 wt%, the properties of Ni-Mo-B catalyst is best, when the reaction time of 120 min, DNT conversion rate of 99.8%, the selectivity of TDA is 100%. And amorphous Ni-Mo-B catalyst using 7 consecutive, the DNT conversion rate of 69.6% and selectivity of TDA is 85.7%.