Study On Synthesis Kinetics And High Gravity Enhanced Synthesis Process Of Vinylidene Chloride

As an important organic raw material intermediate,vinylidene chloride（VDC）is the main raw material for the production of HCFC substitutes.It is also an important polymer monomer.Its polymers and copolymers have unique properties,such as low air permeability,light resistance,oil resistance,shrinkage,good transparency and non-flammability.Synthesis of synthetic resins,latex,fireproof materials,food and chemical packaging materials and other manufactured products.At present,the liquid phase saponification of1,1,2-trichloroethane（112TCE）is the most widely used method to produce VDC,especially Na OH method.However,the traditional stirred tank reactor（STR）used in the saponification unit in industrial production has some problems,such as poor mixing effect,long reaction time,low production capacity and large equipment size.It is urgent to develop a new saponification reactor.In this paper,the kinetic process of HCl removal reaction between112TCE and Na OH will be studied,so as to provide theoretical data for the optimization of new saponification reactor and reaction process.In this paper,the reaction mechanism and kinetic parameters of 112TCE and Na OH were simulated and calculated by Density Functional Theory（DFT）.Then the reaction kinetics was explored by combining conductivity method and equal rate ratio method.Finally,the synthetic process of 112TCE dehydrochlorination reaction was studied by using rotating packed bed（RPB）as a new saponification reactor and comparing STR,and the effects of different operating conditions on the yield of VDC were investigated.The main conclusions of the experiment are as follows:1.Through DFT simulation,it is clear that the three parallel reactions of112TCE and Na OH are the elementary reactions of haloalkanes and strong basic nucleophiles.The basic data of the three reactions were analyzed by transition state search and intrinsic reaction coordinate（IRC）,and the kinetic parameters such as pre-exponential factor,activation energy and reaction rate constant were obtained by calculation.The simulation results showed that the reaction rates of cis-1,2-dichloroethylene（C12DE）and trans-1,2-dichloroethylene（T12DE）were basically the same.In one order of magnitude,the reaction rate of VDC was three orders of magnitude higher than the above two reactions,It’s the main reaction.2.The kinetic experiment was carried out by conductance method,and the kinetic parameters of the total reaction process between 112TCE and Na OH were determined.Then the kinetic parameters such as activation energy and pre-exponential factor of three parallel reaction processes were analyzed by equal rate ratio method,and the expression of kinetic equation was obtained.The kinetic characteristics of the main and side reactions measured in the experiment are consistent with the results of DFT simulation.3.The process of 112TCE saponification reaction to synthesize VDC in STR and RPB was optimized.The apparent rate constants of the reaction in the STR and RPB reactors under optimized operating conditions are 2.27×10^-4L·mol^-1·s^-1 and 6.0×10^-3 L·mol^-1·s^-1,respectively.The interphase transfer of oil-water two-phase reactants in RPB is greatly enhanced,resulting in a great increase in the apparent reaction rate.