Preparation And Application Of Porous Carbon Coated Honeycomb Ceramic Monolithic Catalyst

The demand of 1,1,2-trichoroethylene（TCE）,a new refrigerant HFC-134 raw material,is increasing in the recent yeas.And it is a organochlorine product with good prospect.Generally,the synthesis of TCE is conducted by the vapor dehydrochlorination of 1,1,2,2-tetrachloroethane catalyzed by activated carbon catalyst.However,there are some disadvantages for activated carbon catalyst,such as low activity and poor stability.Combining the advantages of porous carbon and monolithic catalyst,porous carbon coated ceramic honeycomb monolithic catalyst has been widely applied in the gas-solid two phase reactions.In order to solve the deficiency of activated carbon,some porous carbon coated ceramic honeycomb monolithic catalysts had been prepared from different carbon sources and with different properties,and used for the dehydrochlorination reaction of1,1,2,2-tetrachloroethane.Firstly,using furfuryl alcohol resin as carbon source,a series of porous carbon coated ceramic honeycomb monolithic catalysts were prepared by adjusting carbonization temperature.And the physicochemical properties were characterized by methods of TG,SEM,N₂ physical absorption and TPD.These catalysts were applied for the dehydrochlorination reaction of 1,1,2,2-tetrachloroethane to TCE.The results showed that when the carbonization temperature was above 800oC,the acidic oxygenated groups on the surface of the catalyst could be almost eliminated and the large specific surface area and abundant mesoporous structure could be maintained,resulting in the best catalytic performance.On the basis of the above results,the dicyandiamide was selected as the nitrogen source and three different ways of doping N element were chosen to study the effect of doping way on the catalytic performance of the catalysts prepared by low temperature carbonization.The results revealed that the N-doped catalysts showed better catalytic performance compared with the catalysts without doping nitrogen and the catalysts with good catalytic performance could also be prepared under low carbonization temperature by doping nitrogen.Moreover,porous carbon coated ceramic honeycomb monolithic catalysts were prepared by using starch as carbon source.The influences of starch sorts,gelatinization time,carbonization temperature,and diammonium phosphate modification on the carbon loading and the porous structure were studied.The results showed that the catalyst prepared by using natural starch as carbon source had low porous carbon loading coverage and the proper porous structure could not be formed.Therefore,further study is necessary.