Optimization And Mechanism Analysis Of The Synthesis Of Chloropropyl Chloride By Chlorosulfonic Acid

2-chloropropionyl chloride is an important organic chemical raw material,which is widely used in medicine,printing and dyeing,pesticide,and many other fields.Especially in recent years,with the increasing market demand of ibuprofen series used for antipyretic and analgesic drugs at home and abroad,2-chloropropionyl chloride,as an important intermediate for the synthesis of ibuprofen,can not meet the market demand.At present,the mainstream production process is a mostly batch process,which has the disadvantages of low production efficiency,poor self-control level,product quality fluctuation,high production cost,and so on.Therefore,this paper carried out the related research work of continuous process.Firstly,because of the shortcomings of slow reaction speed and poor selectivity in the current process,2-chloropropionyl chloride was synthesized from propionyl chloride chloride with chlorine gas as catalyst and oxygen as side reaction inhibitor in a selfdesigned experimental device.The time-conversion-selectivity curves of the reaction were analyzed and the related comparative experiments were carried out to obtain the basic characteristics and preliminary rules of the reaction.Then,through orthogonal and univariate experiments,the factors influencing the product yield(propionyl chloride to catalyst mass ratio;chlorine to oxygen ratio(molar ratio);chlorine flow rate;reaction temperature)were optimized,and the rules of reaction speed and product selectivity were obtained.The optimum technological conditions were: reaction temperature 40 C,chlorine flow 60L/h,catalyst ratio(mass ratio)is 100:6 and the ratio of chlorine to oxygen(molar ratio)is 100:5.5.Under these conditions,the reaction time was 3 hours and the yield of 2-chloropropionyl chloride was above 97%.It greatly improves the reaction speed and solves the problem of fast chlorine passage,more side reactions,and lower selectivity.Secondly,in order to better explain the experimental phenomena and reaction rules,the formation paths of 2-chloropropyl chloride,by-product 3-chloropropyl chloride,2,3-dichloropropionyl chloride,and 2,2-dichloropropionyl chloride were designed by Gaussian software.The transition states and activation energy of each reaction were obtained.The formation paths of 2-chloropropyl chloride,3-chloropropyl chloride,2-dichloropropionyl chloride and 2,2-dichloropropionyl chloride were determined Path.The results show that the reaction of product 2-chloropropyl chloride is ion-based reaction,and the selectivity of main the reaction can be improved by increasing catalyst.The by-product 3-chloropropyl chloride,2,3-dichloropropionyl chloride and 2,2-dichloropropionyl chloride are free radical reactions.Oxygen can capture the free radicals in the reaction process,thus inhibiting the occurrence of side reactions.Finally,the process simulation of 2-chloropropyl chloride production process of10000 tons /year was carried out by ASPEN PLUS software,and the key equipment was optimized.Through the optimization of the theoretical plate number,feed plate position,and reflux ratio of the delight distillation column and product distillation column,the optimal process scheme and process parameters were established,which provided technical support for the continuous production of the plant.