The Inactivation Mechanism of Hydrochlorination of Acetylene Using Mercury-Free Catalysts

For PVC production, due to the limited oil reserves in China and oil price soaring all over the world, the carbide route is more economically advantageous and will remain to be the main process for PVC production in China for a long time in the future.

Mercury mercury catalyst serious wastage and pollution problems in the process of PVC production, it is urgent to develop non-mercury catalyst to instead mercury catalyst. Our laboratory has had some outcome of the development of mercury-free, chosen catalyst system of CuBi-PO4/SiO2. The catalyst is non-toxic, and it will solve the problem of pollution and the loss of mercury of PVC production. Its reactivity can be achieved 90%, and it can be regenerated after reaction to use in cycle, so that the catalyst has good application prospect. Fast inactivation is current problems of CuBi-PO4/SiO2 catalyst. By studying redients the mechanism of inactivation, to reduce the rate of catalyst deactivation and maintain the catalytic activity，we will provide technical support for the development of mercury-free catalyst and the reaction process.

Response to the issues in the micro-devices using high temperature (200 ℃), high space velocity of acetylene (360h-1) to accelerate the inactivation caused by experimental CuBi-PO4/SiO2 investigated the mechanism of catalyst deactivation, and make the characterization of catalyst to analyze qualitatively and quantitatively for CuBi-PO4/SiO2 catalyst before and after reaction and regeneration，by means of a wide range such as carbon content analysis, electron microscopy, X ray diffraction，results showed that: (1) recycling in a number of the early reaction Guitar carbon catalyst is the main reason for inactivation; After several rounds of regeneration after the loss of active component affecting the main reason for the catalytic activity. (2) of the polymerization reaction of acetylene is the catalyst causes the formation of carbon knot, has nothing to do with the existence of vinyl chloride. (3) binding of carbon catalyst and catalytic activity is directly proportional to the extent, affected by temperature. (4) the main catalyst for the end of carbon-carbon and carbon-saturated alkanes alkenes, non-chlorinated hydrocarbons, carbon also shows that node has nothing to do with vinyl chloride. (5)a catalyst active component element bismuth HCl atmosphere at high temperature, the existence of phosphate into the form of chloride, easily volatile, resulting in the loss of active component. (6) the process of regeneration of trace water vapor, so that elements from bismuth chloride phosphate resume to avoid the form of bismuth chloride in volatile elements, while optimizing the active component in the distribution of the surface of the catalyst, a catalyst for regeneration activity to maintain a significant role.

Keywords： Calcium carbide; VCM; Mercury-free catalyst; Carbon formation; The loss of active component