Research Of Continuous Microwave Reactor For Chloroacetic Acid

Chloroacetic acid was a particularly important in fine chemical production,which could be synthesized on a variety of industrial important organic compounds and intermediates and be used for the pesticide and medicine because of containing a chlorine atom and a carboxy group.Coupled with the large consumption and shortage of energy resources at home and abroad in recent years,chloroacetic acid was more and more taken seriously.However,the production capacity of chloroacetic acid was still low,in addition,chloroacetic acid was used in organic chemical intermediates incrementally and the demand for chloroacetic acid was considerable in European countries.The manufacturers of chloroacetic acid were all over China,but the production capacity of chloroacetic acid was still in the below at homedue to small scale and environmental and human factors.Therefore,it was greatly necessary to research a kind of chloroacetic acid,which could not only increase the chloroacetic acid production and reduce the cost but also could be the new technology of green environmental protection,had become an important topic of current study at home and abroad.It should be committed to the development of catalytic systems at present and the synthesis of acetyl chloride is the key to chlorination reaction,if a kind of cocatalyst,which could increase the concentration of acetyl chloride directly,could be developed,the quantity of chloroacetic acid would be increased significantly.In addition,how to improve the activity and selectivity of chlorination reaction and the mastery and simplicity of follow-up process would be an amportant topic of chloroacetic industry at home and abroad in the future.Production of chloroacetic acid contained batch process and continuous process.One of the most important process is the first step chlorination reaction,which is often added for sulfur as the catalyst generally,but sulfur as the catalyst had greatly resulted in the consumption of raw material and seriously environmental pollution.The acetic anhydride method had been widely applied in the factory of chloroacetic acid at home and abroad,but some details were wrong with production,such as lower activity and selectivity of chlorination reaction,slower reaction rate and so on,which remained to be solved.In this paper,the continuous microwave was used in front of previous microwave for the first time(that is,the frequency of microwave and the temperature of water bath was used for controlling reaction temperature directly,through which the temperature of a reaction is regulated.The catalyst acetic anhydride,reaction temperature,microwave power and catalyst promoter to the influence of chlorination reaction activity and selectivity is studied respectively,and the catalytic mechanism is also discussed in the system.This research was mainly divided into three parts:In the first part,the catalyst acetic anhydride,the microwave power and reaction temperature on the influence of the activity and selectivity of chlorination reaction were discussed in the microwave reaction system,drawing that the volume fraction of acetic anhydride in acetic acid of 20%,controlling the reaction time 3.5h and adjusting the microwave power 300W to make reaction temperature stabilize at 95? were the optimum conditions,under this which the mass fraction of chloroacetic acid was up to the best 94.31%and the selectivity reached to the top 93.01%.In the second part,the influence of anhydrous ferric chloride,ferric chloride chloride silica load,zinc chloride and polymeric ferric chloride to the activity and selectivity of chlorination reaction and the reason for resulting to this effect were discussed,drawing that the active intensity of catalytic was anhydrous ferric chloride,hexahydrous ferric chloride,concentrated sulfuric acid,ferric chloride by the load of activated carbon,ferric chloride by the load of silica,zinc chloride,polymerization ferric trichloride from high to low in turn and the assistant catalytic effect of anhydrous ferric chloride was the best,the mass fraction of chloroacetic acid and the reaction selectivity reaching to the maximum 98.11%and 98.58%respectively.In the third part,the reaction mechanism of chlorination reaction and the assistant catalytic mechanism of the anhydrous ferric chloride,concentrated sulfuric acid and zinc chloride were discussed in the microwave system.