Study On The Synthesis Of VDC Via Vapor-phase Catalytic Reaction Of TCE

As an important basic chemical raw material, vinylidene chloride is widely used in many fields. It can be used to produce polyvinylidene chloride and many kinds of multipolymer. It is also used for Fibers,resins and food Packages. The tradition manufacturing technique of vinylidene chloride has many Problems, such as pollution, high cost,and so on. With the improvement of living standards and the importance of food safety, People have more requirements on the vinylidene chloride than before. The research of developing more efficient and green vinylidene chloride industrial production technology is of great importance. While the vapor phase crack production process is almost no waste emissions. This paper investigates the carrier, alkali metal halide and inhibitor on the dehydrochlorination reaction, and the results show that the catalytic performance of the catalyst system constructed is not ideal, The fast low-carbon olefin polymerization lead to low catalytic performance and stability. Try to use the new catalyst may be able to solve the problem.Therefore, a series of graphitic carbon nitride materials(C3N4) have been synthesized using dicyandiamide as precursor through nanocasting method. Studies show that the conversion rate of 1,1,2-trichloroethane is 41.82%, and the selectivity of vinylidene chloride is 86.51%. It proves that carbon nitride catalysts exhibite excellent catlaytic performance. We also study the catalytic performance of carbon nitride materials prepared under different atmosphere. Studies show that the conversion rate of 1,1,2-trichloroethane is 73.36%, and the selectivity of vinylidene chloride is 100%. It shows that the graphitic carbon nitride materials has excellent ability in vapor-phase catalytic reaction, and shows immeasurable application prospects. The physicochemical properties of the synthesized samples are characterized by X-ray diffraction, SEM, FTIR and elemental analysis. Results show that we successfully prepare the g-C3N4 catalyst through roasting cyanide diamine under high temperature. But we don’t get how the atmosphere to affect polycondensation reaction process. We propose the carbon anion reaction base that strong alkaline g-C3N4 as nucleophilic reagent adsorption, makes the 1,1,2-trichloroethane dehydrochlorinate selectivity to generate vinylidene chloride. We speculate that active sites of gas phase catalytic reaction may be the N atoms connected the three triazine structure, and the atmosphere is conducive to form the structure.