Fundamental Research On Synthesis Of Ethyl Trifluoroacetate

Ethyl trifluoroacetate(ETFA),a colorless transparent liquid with highly volatile,is an important organic chemical material.It is widely used for preparing a variety of synthetic pesticides,pharmaceuticals,dyes,and liquid crystal.Therefore,the market demand of ETFA is gradually increasing and the production of ETFA grows greatly.At present,the major method to synthesis of ETFA is direct esterification reaction of trifluoroacetic acid with ethanol under the catalysis of sulfuric acid;but there are some mian drawbacks of this method,such as serious corrosion on product,serious pollution and subsequent processing complex.A new synthesis process for ETFA,the esterification of TFA and ethanol to form ETFA and water is investigated in this work,taking the autocatalysis of TFA into consideration.The research focused on the following aspect:(1)The physical properties of ETFA were measured and correlated using precision equipments.Density measurement of ETFA was carried out by using a calibrated glass pycnometer with a bulb volume of 50 cm.The density data were fitted to a quadratic polynomial equation.The liquid kinematic viscosity of ETFA was obtained by utilizing a commercial capillary viscometer of Ubbelohde type with capillary diameter of 0.36 mm and the viscosity data were regressed to the Andrade equation.The saturated vapor pressure of Ethyl trifluoroacetate was measured by a static method.Antoine equation is used to describe the relationship between temperature and vapor pressure.In addition,the molar evaporation enthalpy was estimated by the Clausius-Clapeyron equation.(2)The kinetics for synthesis of ETFA was investigated with TFA and EtOH over the autocatalysis of TFA in a batch stirred-tank reactor.The effects of reaction temperature and reactant molar ratio on reaction rate were investigated,and a homogeneous kinetics model was established according to a possible reaction mechanism.The reaction rate constant?activation energy and other optimal kinetic parameters were obtained by using the MatLab programming.According to the result,this esterification is an endothermic reaction,the heat of reaction is 17.5085 kJ/mol,the activation energy is 42.2966 kJ/mol.(3)Isobaric vapor-liquid equilibrium(VLE)data for binary systems(TFA-H2O,ETFA-EtOH,ETFA-TFA)at 101.3 kPa were measured in a double circulating still of modified Rose type.All binary experimental data were correlated by NRTL and Wilson models,and the binary interaction parameters of both models have been obtained by simplex method.The vapor liquid equilibrium data was tested by Herington semi-empirical method,and the result showed that experimental data met the thermodynamic consistency test.