Preparation of dimethyl-substituted cumene hydroperoxides
The article investigates the kinetics of the oxidation reaction of dimethyl cumene to hydroperoxides with molecular oxygen in the presence of N-hydroxyphthalimide.. In order to obtain information on the kinetic laws related to the process of dimethyl cumene oxidation in the presence of N-hydroxyphthalimide, a series of experiments was conducted. The experimental data related to the kinetics of hydroperoxides and non-reaction products formation provided the mathematical model that adequately describes the change of all components of the reaction at the time.
It was established that the role of N-hydroxyphthalimide as the initiator of the process is determined by the fact that its interaction with oxygen results in the stationary concentration of N-phthalimide radicals, which initiate oxidation process in their interaction with hydrocarbon.
The experimentally tested high-selective method used for the synthesis of hydroperoxides by liquid-phase catalytic dimethyl cumene oxidation can become the basis of a single universal method for producing xylenols that meets the latest environmental and economic requirements. The suggested mathematical model of the dimethyl cumene oxidation to hydroperoxides in the presence of NHPI is original and may be of interest for calculating the kinetics of similar reactions involving other alkylaromatic hydrocarbons.
The liquid phase oxidation of alkylaromatic hydrocarbons serves as the basis for constant development of the new methods for producing various oxygenated compounds, which are widely used in the synthesis of polymeric materials. The production sector is familiar with such processes as the “cumene” method of preparation of phenol and acetone or joint synthesis of styrene and propylene oxide (the “chalcone” process) (1). These processes are based on the selective preparation of the corresponding hydroperoxides. The appearance of the new method of selective production of hydroperoxides using N-hydroxyphthalimide (NHPI) significantly expands the range of refinable raw materials and, consequently, the resulting products of petrochemical synthesis (2, 3). In particular, this method provides synthesis of valuable organic products by obtaining various alkylaromatic hydroperoxides, which is practically impossible by using conventional methods (4). Thus, for example, one of the promising methods is the method used for producing xylenes from xylenols through preparing by-products - isopropyl derivatives, and the corres ...