Investigation Of N-methylation And Degradation Of Dye In Aqueous Solution Catalyzed By Polyoxometalate As Assistant Catalyst

In this paper, we investigated the preparation of N, N-dimethyl aniline (DMA) with aniline-methonal and photocatalyzed degradation of dye waste water, in which the reaction systems were catalyzed by polyoxometalate containing composite. On one hand, the experiments indicate that H3PW12O40/SiO2 showed the higher selectivity for N-methylation in the preparation of N, N-bimethyl aniline. The best experimental condition was: reaction temperature 320℃; reacting velocity of flow 12.5 ml/h; molar ratio of reactants 1:4; POM in composite catalyst 30%. In this condition, DMA attached 55.7% yield, which provided valuable information for exploring new catalyst in preparation of DMA. On the other hand, the degradation of Alizarin red was affected by different type catalyst, content of POM in catalyst, dosage of catalyst, and original concentration of Alizarin red solution. The best condition is: Cr3OSiW12(5%)—TiO2 (95%) system, dosage of catalyst 15 mg, concentration of Alizarin red solution 0.1mmol/l. As compared to pure TiO2, catalytic activity of KH2[Cr3O(CH3COO)6(H2O)3](SiW12O40)/TiO2 significantly enhanced, which the decolor ratio could reach 74.6% attributed to the synergistic effect resulting from the combination of POM and titania. This research not only established the theoretical foundation in the area of exploration of new nonhomogenous photocatalyst comparative to TiO2, but also provided important experimental data for purifying industrial waste water by POM as assistant catalyst.