Acetic Anhydride Hydrolysis Reaction Thermal Runaway Risk

There are thermal runaway risks during the hydrolysis of acetic anhydride for its exothermal characteristic.In this paper,Reaction Calorimeter(RCle) was used to measure the thermodynamics parameters of this hydrolysis in semi-batch reactor to study the thermal safety of chemical reaction.First of all,a series of experiments were carried out with RCle to study the influence of stirring speed and dosing time to some parameters of the reaction.Second,by establishing the reaction kinetics model and non-linear simulation with the measured thermodynamics parameters,can the kinetics parameters such as reaction order n,activated energy E and frequency factor A be obtained.Finally,by referring to the expressions,the Exothermicity parameter Ex and Reactivity parameter Ry were obtained to establish the safety boundary diagram.And combining with the parameters such asΔT_ad,the risk class of thermal runaway criticality was studied.After that,Rapid Screening Device(RSD) was used to study the thermal decomposition of the hydrolysate.The results indicate that,for the hydrolysis reaction of acetic anhydride under given condition,the calculation show that,the reaction order to acetic anhydride is 1,activated energy E is 57 kJ/mol,frequency factor A is 1.8×10⁷ mol/J.Based on the safety boundary diagram,during the area of E_x＜1.615andR_y＞0.834,the reaction can be thought to be safe since there is no thermal accumulation and thus no runaway is observed.In addition, the hydrolysate,i.e.acetum,can decompose at about 100℃,and the pressure raise up fast.