微波作用下的乙酸乙酯合成反应动力学

Kinetics of Catalytic Synthesis of Ethyl Acetate under Microwave Irradiation

为揭示微波辐射效应对非均相酯化反应动力学的影响,研究了微波加热催化合成乙酸乙酯的酯化反应动力学,并与常规动力学作了对比。在自制微波功率连续可调、红外测温已校正的反应装置中,重复测定了反应温度为60,65,70和75℃时的正、逆反应速率常数,得到了Arrhenius方程参数。微波加热下的反应活化能为51.719 kJ/mol,指前因子为582.9;常规水浴加热下的反应活化能为48.581 kJ/mol,指前因子为169.2。研究结果表明,在研究的反应温度范围内,微波改变了反应动力学,加快了反应速率,存在微波非热效应,但并不改变反应平衡常数。

in order to reveal the microwave irradiation effect on the heterogeneous esterification reactions, the kinetics of catalytic synthesis of ethyl acetate under microwave irradiation was studied, and then comparison was made with the conventional kinetics. A set of microwave reaction apparatus was designed with a continuously adjustable microwave power and an infrared temperature sensor. Experiments were carried out at the reaction temperature of 60, 65, 70 and 75 ℃, and the rate constants and Arrhenius parameters were then obtained. Under the microwave heating, the activation energy is 51.719 k J/tool and the pre-exponential factor is 582.9; while under conventional waterbath heating, the reaction activation energy and pre-exponential factor are 48.581 k J/tool and 169.2, respectively. The experimental results show that under microwave heating, the reaction kinetics has been changed, and the reaction rate is enhanced within certain reaction temperature range, which indicates the existence of microwave non-thermal effect. However, the reaction equilibrium constant is not changed between the microwave and conventional heating.