Dissolution Mechanism Of Vinyl Chloride In Ionic Liquids

Vinyl chloride is an important basic chemical raw material,and the study of its basic properties is of great significance.But the existing document does not study vinyl chloride in depth.So,in this thesis,we will study the mechanism of interaction of vinyl chloride gas molecules in ionic liquids to find their solubility in ionic liquids and provide necessary data support and theoretical basis for industrial applications of ionic liquids such as acetylene hydrochlorination,based on the characteristics of ionic liquid’s extremely low saturated vapor pressure and liquid state at normal temperature,and the methods of chemical experiments and computer simulation.The second chapter of this thesis introduces experimental data analysis and chemical calculation simulation.In the experimental part,the specific experimental method used is pressure drop method,which estimates the gas solubility in the ionic liquids by the amount of pressure change of the system before and after the ionic liquid absorbs the gas.And [Bmim]+[CH3COO]-,[Bmim]+[Cl]-,[Bmim]+[PF6]-,[Bmim]+[BF4]-these four ionic liquids are selected to measure their solubility.At the same time,quantum chemical calculations are carried out on these four ionic liquids,and the solubility of gases in ionic liquids is simulated by using the COSMO-RS method.By comparing simulation and experiment,we find that the solubility of the simulated vinyl chloride gas and the solubility obtained by the experiment matches each other.This shows that we can use the COSMO-RS method to quickly predict the solubility,which greatly reduces the time we need to use experimental measurements.On the basis of the above conclusions,we have conducted in-depth research on ionic liquids such as 1-butyl-3-methylimidazole phosphate dimethyl salt and quoted the concept of symmetry.We also have worked on designing a variety of anions with P atoms as the center of symmetry and measuring the solubility of each ionic liquid at room temperature and pressure.And these experiments show that in the same type of ionic liquids,the solubility of vinyl chloride gas molecules in the ionic liquid is mainly related to the number of atoms that make up the ionic liquid,and it has little to do withthe structure of the anion of the ionic liquid.In addition,we have studied the influence of the ionic liquids commonly used in the laboratory,such as [Bmim]+[CH3COO]-,[Bmim]+[Cl]-,[Bmim]+[PF6]-,[Bmim]+[BF4]-on the solubility of vinyl chloride gas molecules.Through quantum chemistry simulation,we find that not all the anions and the vinyl chloride gas molecules have strong interactions.At the same time,the places where hydrogen bonds are formed are often where the local charges are concentrated.So we can use the symmetry of ionic liquids to quickly judge the ability of ionic liquids to absorb vinyl chloride gas molecules.Based on the above conclusions,this paper applies the solubility law of vinyl chloride in ionic liquid to the process of acetylene hydrochlorination tail gas treatment.After the tail gas generated by acetylene hydrochlorination reaction is absorbed with water,the main components of the tail gas are vinyl chloride and Composition of acetylene.Using the method of COSMO-RS,we quickly predicted the mole fraction of acetylene and vinyl chloride gas in 55 ionic liquids,and studied the relationship between the structure of ionic liquid and the absorption capacity and separation selectivity of gas in ionic liquid.The results show that the degree of local charge concentration and the number of atoms required to form an ionic liquid have different effects on the molecules of acetylene and vinyl chloride.Reducing the concentration of local charges and increasing the number of atoms required to form an ionic liquid can effectively increase the selectivity of the ionic liquid.At the same time,we found that the solubility of vinyl chloride molecules in the ionic liquid has not decreased,which also guarantees The absorption capacity of vinyl chloride in ionic liquids is shown.Therefore,when designing ionic liquids for separating acetylene hydrochlorination tail gas,we can choose ionic liquids with a more dispersed charge distribution and a larger number of atoms that make up the ionic liquid.