Synthesis Of Hydrogen Storage Alloy Catalytic Hydrogenation Of Nitro Toluene And Aniline Derivatives

P-toluidine, which is used in medicine, pesticide, pigments and other fields, is obtained by catalytic reduction of p-nitrotoluene in different reaction systems. In recent years, hydrogen storage alloy has been developed as a new type of hydrogenation (dehydrogenation) catalyst. There are several advantages of the alloy, such as:it can hydrogenate the compounds under mild conditions, it has good catalytic activity, and the reaction has high selectivity when the catalyst is used. Because of the characteristics of the alloy, it has become a good catalyst for the hydrogenation process. The research about the hydrogen storage alloy which is used as an electrode in electrochemical synthesis has already been reported a lot, but there are rare reports about the direct hydrogenation of compounds with the alloy powder. Therefore, The hydrogen storage alloys and P-toluidine have been studied in this paper.In this paper, ML(Ni3.69Co0.72Mn0.35Al0.24) and La2(NiCoAl)7 hydrogen storage alloys were prepared using the metal materials(purity higher than 99%) by medium frequency vacuum induction melting under the protection of the Ar gas. The structures of the alloys were characterized by X-ray diffraction (XRD). The results reveal that the XRD peaks of two kinds of hydrogen storage alloys were sharp. The hydrogen storage alloys were nano-crystalline structure, and its grain size below 50nm. The electrochemical properties of the alloys were tested by LAND Test Systems and CHI660D ChemStation. The results reveal that the two kinds of alloys could be activated easily and the maximum discharge capacity appeared in 3 times charge-discharge cycles. The electrochemical properties of the alloys are related to alloy compositions and cell morphology. The capacity of A2B7-type hydrogen storage alloy is higher than that of AB5-type alloy. Otherwise, the A2B7-type hydrogen storage alloy could be powdered more easily, so the cycle performance is not better than the AB5-type alloy. In addition, the high-rate performance of A2B7-type alloy is better than AB5-type alloy. In a word, A2B7-type hydrogen storage alloy has better electrochemical properties.The hydrides formed by doping AB5-type and A2B7-type hydrogen storage alloys are used as the hydrogen sources and catalysts for hydrogenation of p-nitrotoluene to p-toluidine. GC-MS and GC were used to make qualitative analysis and quantitative analysis on the products. The results reveal that the catalysts can hydrogenate the p-nitrotoluene to p-toluidine under the mild conditions with no by-products, the selectivity of p-toluidine is up to 100%, and the reaction catalyst and reaction system could be separated easily after the reaction. The effect of the amount of catalyst, solvent, reaction temperature and reaction time during the reaction process is discussed in details. The results reveal that the amount of the catalyst is closely related to the catalytic activity of hydrogen. The nature of the solvent has a significant effect on the reaction. The performace of the catalyst is the best when the ethanol or toluene is used as solvent, and it has maintained high catalytic activity after repeating for 5 times. Under the same external conditions, the catalytic properties of A2B7 type alloy are better than that of AB5 type alloy.The p-dimethylamino benzaldehyde and p-methyl benzyl chloride have been synthesized by p-toluidine and characterized by infrared spectroscopy, mass spectroscopy and nuclear magnetic resonance spectroscopy, which confirmed that the synthetic product is the target product.