Photocatalytic Synthesis Of Nitrogen-containing Organic Polymerized Monomers

Alkylamine compound is an important chemical raw material,widely used in medicine,agriculture,dyeing and other fields.The preparation of alkylamines through the N-alkylation reaction of semiconductor photocatalytic amines and alcohols has received increasing attention.This synthesis method has the advantages of mild and controllable reaction conditions,a wide range of raw material sources,and fewer byproducts.In this experiment,a series of P25 supported metal particle photocatalyst particles(M-P25)were prepared by photochemical deposition method using metal salt as the precursor and titanium dioxide(P25)as the photoactive carrier.And XRD,HRTEM analysis and testing methods were used to characterize the prepared M-P25.Under light conditions,the above-mentioned photocatalyst was used to catalyze the multi-step N-methylation reaction of diethanolamine(DEA)and methanol to produce N-methyldiethanolamine(MDEA).The reaction results were qualitatively and quantitatively analyzed by means of 1H NMR nuclear magnetic instrument And calculate the yield of the target product MDEA.The photocatalytic activity of M-P25 prepared by photodeposition method determines the yield of MDEA.First,Cu-P25 with different metal loadings was used to photocatalyze the above reaction.It was found that the Cu-P25 photocatalyst synthesized by photodeposition method can catalyze the N-methylation reaction of DMA and methanol,but the target product MDEA yield is lower,MDEA The yield of the metal has a great relationship with the loading of the metal Cu.When the Cu loading on the P25 is 0.3wt%,the yield of MDEA is the highest;other kinds of metals are also photocatalyzed with the loading of 0.3wt%.Under the same conditions,the photocatalytic activity of Pd-P25 is the highest,and the yield of MDEA is up to 64.69%;the additional P25 carrier is mixed with the original photodeposition method Cu-P25 particles to obtain a composite photocatalyst Cu-P25 / P25,Cu-The photocatalytic activity of P25 / P25 in the reaction system is much higher than that of Cu-P25;further experiments found that the amount of P25 carrier also has an effect on the activity of the photocatalyst.A series of experimental results show that Cu-P25 and P25 powder are the best The compounding ratio is about 1/2;some external micro-environmental factors in the photocatalytic system can also largely affect the yield of the target product MDEA.Considering the above factors,the composite photocatalyst Cu(0.3)-P25(0.5)/ P25(1.0)was found to have the highest photocatalysis,and the target product MDEA yield in the nitrogen atmosphere reached 81.7% in 12 h.Through the experimental results,it is speculated that the low performance of the original photodeposition method is related to its structure-oriented photodeposition mechanism;and through a comparative study,the important effect of the shielding effect between the photocatalyst particles on the catalyst performance was discovered and explained.Our further experiments found that some internal and external environmental factors in the photocatalytic system can also greatly affect the catalytic activity of the photocatalyst.