Kinetics of Hydroxychlorination of Styrene Using Hydrogen Peroxide and Hydrochloric Acid

Abstract

Styrene chlorohydrin is an important intermediate used in the manufacturing of high-value specialty chemicals. This paper focuses on understanding the kinetic aspects of styrene chlorohydrin production using hydrogen peroxide and hydrochloric acid. For this two-phase non-catalytic system, lab-scale initial rate experiments are conducted to assess the impact of key design parameters, such as reaction temperature, speed of agitation, and phase volume fraction, on the observed reaction rate. Based on these studies, it has been shown that this reaction takes place in the aqueous phase and the apparent order of reaction with respect to styrene, hydrogen peroxide and hydrochloric acid is approximately one, one and two, respectively. The corresponding Hatta number values are much smaller than one and the enhancement factor is approximately one, confirming that the system operates in regime I. Subsequently, a detailed reaction mechanism is proposed to capture the composition profiles of styrene chlorohydrin as well as the other major side products. The proposed model is then validated against composition trends observed in full-batch experiments. The model captured concentration profiles accurately, yielding sum of squared error (SSE) values around three. This model can be utilized to design and optimize the commercial manufacturing process for styrene chlorohydrin.