Kinetics And Process Simulation Of Propylene Carbonate Synthesis

The cycloaddition reaction of carbon oxide and propylene oxide to produce propylene carbonate not only conforms to the green and sustainable development concept of“carbon peak and carbon neutral”,but also opens up a new route for non-petroleum raw materials.The produced propylene carbonate is used in the chemical industry.The field has important application value.However,the chemical properties of carbon dioxide are extremely inactive.To achieve the chemical fixation and resource conversion of carbon dioxide under relatively mild conditions,the choice of catalyst is very important.Ionic liquids have great industrial value for the synthesis of propylene carbonate from carbon dioxide and propylene oxide due to their excellent catalytic performance.In this paper,[BMIM]Br ionic liquid was synthesized first,and then[BMIM]Br ionic liquid was modified to obtain MIL ionic liquid,and then additives I and II were added to prepare a composite modified ionic liquid（CMIL）catalytic system.Using CMIL to catalyze CO₂and propylene oxide（PO）to synthesize propylene carbonate（PC）,optimize the process parameters,and investigate the effects of reaction temperature,reaction pressure,reaction time,catalyst dosage,etc.on the catalysis by combining single factor and orthogonal experiments.The effect of performance and the service life of the catalyst were studied.By testing the solubility of CO₂and basic assumptions,combined with kinetic experimental research,the kinetic equation of the synthesis of propylene carbonate by CMIL catalyzed by CO₂and PO was established.Aspen plus was used to simulate its catalytic process,which is a further industrial device.Selection design and industrialized production provide theoretical basis and data support.The experimental results show that the synthesis of[BMIM]Br ionic liquid is the target product,but the catalytic effect is poor when used alone.The CMIL ionic liquid catalytic system obtained by compound modification has good catalytic performance.The optimal reaction process parameters are:The reaction temperature is 100°C,the pressure is 1.5MPa,the time is 1.5h,and the amount of catalyst is 2.0%.Under these conditions,the conversion rate of the reactants is 99.98%,and the selectivity of the product is 98.87%.The experimental results show that the solubility of CO₂in the reactant PO is very large at room temperature,and 144.38L of carbon dioxide can be dissolved per liter of PO.The solubility of CO₂in the reactant PO and the product PC at 100°C is not much different.According to the hypothetical nucleophilic reaction mechanism of PO synthesis of PC,a kinetic equation is established.Under certain temperature and pressure,the synthesis reaction rate of PC has a linear relationship with catalyst and PO concentration.Through the Aspen Plus chemical simulation software,the CMIL catalytic system catalyzed CO₂and propylene oxide（PO）to synthesize propylene carbonate（PC）process simulation design,and the purity of refined propylene carbonate was as high as 99.8%.