(26g) Experimental Study and Model of Reaction Kinetics of Synthesis of Methacrylic Anhydride

Methacrylic anhydride is widely used as the esterification agent. In this paper, the
reaction kinetics of synthesis of methacrylic anhydride were investigated in a
batch stirred-tank reactor at atmospheric pressure by using methacrylic acid
and acetic anhydride as raw materials. The reactions were carried out under
several temperatures between 343.15 and 363.15K and various starting reactant
compositions. Both the influence of temperature and initial
molar ratio of Methacrylic anhydride to acetic anhydride on reaction kinetics were studied
in a range that is interesting for process design. Base on the characteristics
of the reaction, a typical consecutive reaction mechanism was deduced. Homogeneous
reversible kinetic model of second-order was described, and the reaction rate constants
and activation energy were obtained according to the experimental reaction rate
curves. The kinetic equations for the preparation of methacrylic anhydride from
methacrylic acid and acetic anhydride are as follows:

According to these equations, the first reaction is
an exothermic
reaction and the second reaction is an endothermic reaction. The
reaction kinetic model was in good agreement with the experimental data. The
biggest relative error was nearly 1.5% in the subsequent reaction process.