THE USE OF A POLYMERIZATION MODERATOR BASED ON PARA-PHENYLENEDIAMINES IN THE PRODUCTION OF STYRENE

Currently, two types of reagents are used in industrial styrene production to prevent thermal polymerization during the rectification process: true inhibitors and polymerization retarders. Consumed in the process, the true inhibitor reacts with free radicals and breaks the reaction chain, determining the molecular weight of the polymer. The polymerization moderator reduces the concentration of the most mobile radicals and their lifetime, giving a hydrogen proton to the most reactive free alkyl radical. As a polymerization moderator, dinitrobutylphenol is the most effective, which, according to the degree of exposure to the body, belongs to the first class of danger. The main supplier of dinitrobutylphenol to Russia is the People's Republic of China. The paper considers the possibility of replacing the active styrene polymerization inhibitor with the domestic brand Inflow7007, which is a derivative of para-phenylenediamine. According to the set of characteristics, the new polymerization moderator belongs to moderately dangerous substances of the third hazard class.At the first stage of the work, comparative laboratory studies of four polymerization inhibitors were carried out. The dependence of the inhibitory ability on the concentration of the polymerization moderator, the kinetics of the process was studied, and a comparative analysis of domestic and imported analogues of inhibitory reagents was carried out.Next, an experimental industrial run was conducted at an existing styrene production plant, during which a gradual transition to a domestic inhibitor selected as a result of laboratory research was carried out. The transition was carried out in stages with the gradual replacement of dinitrobutylphenol with an inhibitor of the Inflow 7007 brand. Throughout the entire industrial pilot run, the polymer content in the cubic liquid of the raw styrene separation column was monitored. The conducted studies have shown the high efficiency of the proposed inhibitory system. According to the results of analytical control during the period of pilot tests, it was possible to reduce the average polymer content in the cubic liquid. In addition to increasing the effectiveness of polymerization inhibition in styrene production, the use of the proposed polymerization moderator will solve the problem of import substitution, increase worker safety, and reduce environmental risks.