The Catalyst Performance And Technology In The Catalytic Hydrogenation Of Nitro-aromatic Compounds

The products of nitro aromatics catalytic hydrogenation are widely used in chemical industry, medicine, dyes, pesticides and other fields. This paper studied catalytic hydrogenation of aryl nitro compounds reduction. The key technology of nitro aromatics catalytic hydrogenation selected and prepared the high activity and selectivity catalyst.This paper studied the following catalyst: MoS₂/C catalyst, Mo-Co/C catalyst, MoxN/C catalyst, Ni series catalyst. Carry the catalysts on TGA, SEM, XRD characterization, to determine the composition of compounds. MoS₂/C catalyst was amorphous and calcination temperature fixed on 400℃. The other showed crystalline catalyst.Put these catalysts into nitrobenzene hydrogenation reaction to study their catalytic properties, the conversion rate of nitrobenzene as a factors of this study. Use the GC-MS technique to detect the product of catalytic hydrogenation, obtain the law of the catalytic properties. Analyze the Generation process of the products. I think in this reaction MoS₂ catalyst as a Lewis acid, ethanol as the alkylation reagent generated ethyl cation. Ethyl cation generated methyl cation and carbene by carbon-carbon bond fracture as a result of high temperature and high pressure. In all reaction products, aniline obtained by direct reduction of nitrobenzene, others obtained by hydrogenation of aniline depth. In the generation process of quinoline, nitrobenzene acted a dehydrogenation agentThrough summing up the above analysis, the catalytic properties of MoS₂/C catalyst is the highest. Inspect MoS₂/C catalyst for catalytic hydrogenation reaction of nitrobenzene, select the appropriate process conditions of catalytic hydrogenation, including the surfactant and solvent amount, the parameters enactment of reaction temperature, reaction pressure, reaction time and stirring speed. The optimum reaction condition is that: the surfactant-dodecyl trimethyl ammonium bromide as Reaction auxiliaries 0.5g, ethanol as reaction solvent 20ml, the reaction temperature 150℃, reaction pressure 1.5MPa, reaction time 10h, stirring speed 100rpm. The conversion rate of nitrobenzene is 57.25%.