Determination And Molecular Simulation Of TDI Related Synthesis System

Toluene diisocyanate （TDI） is an important chemical intermediates, which is widelyused in industry. The non-phosgene method is currently the most popular andenvironmentally friendly method to synthesis TDI. But the related system phaseequilibrium data of its basic raw materials has been reported so limited so far, leading todifficulties in TDI synthesis reaction design and its unit operations. Thus, TDI synthesissystem was chosen to be object here. Then the equilibrium properties of its solid-liquidsystem and the gas-liquid equilibrium were respectively studied by experimentaldetermination and molecular simulation method, which provide the key data and newprediction method to non-phosgene synthesis TDI of its industrialization design.These have been done for the solid-liquid equilibrium system. First, the solubilitydata and mixture density of methanol-urethylane, ethanol-urethylane, methanol-2,4-DNT,ethanol-2,4-DNT, methanol-2,4-Diaminotoluene, ethanol-2,4-Diaminotoluene systems atthe range of293.15K³08.15K and atmospheric pressure were respectively got by lasermethod and indirect measurement. Second, excess volumes VEof the systems werecalculated by the mixture density. Then, densities and compositions were correlated withlinear model, and the standard deviations of the regression coefficients are lower than0.5%; Excess molar volumes and compositions were correlated with the Redlich-Kisterequation, and the standard deviations of the regression coefficients are lower than5%.Results show that the linear model and Redlich-Kister can be used to correlate the twomentioned physical properties of the two systems.The Monte Carlo algorithm with molecular simulation was combined and comparedwith experimental result for gas-liquid equilibrium system. First, the ethanol model wasconstructed by TraPPE-UA force field, and the vapor-liquid equilibrium properties at therange of298.15K³38.15K under atmosphere pressure were determined by NVT-Gibbsmethod. The saturated vapor pressure and phase density of ethanol at98.15K³38.15Kwere calculated and prepared with literature data. The average deviation of saturatedvapor pressure is3.5%, and the average deviation of the vapor and liquid density is3.7% and8.2%, which certified the reliability of the ethanol model. Second, ethanol andoxygen model were respectively constructed by TraPPE-UA force field and Coon1987force field. And NpT ensemble with the test particles inserted method was used to predictthe solubilities of O₂-C₂H₅OH system at298.15K and323.15K under the pressure rangefrom2Mpa to8Mpa. Then, the molecular simulation results of solubilities ofO₂-C₂H₅OH system at high pressure were confirmed to be reliable by comparing withexperimental data. At last, simulation results and experimental data were modeled byHenry’s Law and then compared to literature data with the average deviation is10%. Theresults show that: the solubility of oxygen in ethanol increases with pressure anddecreases with temperature in the range of2⁸Mpa and298.15³23.15K.