METHOD OF AUTOMATICALLY CONTROLLING PROCESS OF PRODUCTION OF GLYCEROL DICHLOROHYDRINES VIA ALLYL CHLORIDE HYPOCHLORINATION Russian patent published in 2004 - IPC

FIELD: industrial organic synthesis. SUBSTANCE: in particular, invention relates to improved method for automatically controlling two-reactor process for production of glycerol dichlorohydrines involving reaction of allyl chloride with hypochlorous acid obtained using chlorine and softened water wherein allyl chloride, chlorine, and softened water intakes, pH of hypochlorous acid solution, and redox potential of glycerol dichlorohydrines are controlled. Hypochlorous acid utilized in the process is prepared by interacting emission chlorine (obtained after partial condensation of electrolytic chlorine) having concentration 65-92 % (v/v) with softened water and 20% aqueous sodium hydroxide solution. In this operation, consumption of sodium hydroxide, calculated as 100% substance, is controlled in such a way that it is regarded as principal process stream and stabilized by stabilizing consumption of 20% solution thereof while appropriately correcting concentration of sodium hydroxide in this solution. Simultaneously, softened water is fed using intake proportional to consumption of 100% sodium hydroxide taking into account volume of water coming in the stream of 20% sodium hydroxide solution. Emission chlorine, calculated as 100% substance, is fed proportionally to 100% sodium hydroxide consumption, while appropriately correcting concentration of chlorine in emission chlorine stream and correcting ratios of emission chlorine (as 100%) and sodium hydroxide (as 100%) streams from the pH value of hypochlorous acid thus obtained, which provides predetermined stable stream of hypochlorous acid and predetermined stable and optimal concentration of this acid in its solution. Allyl chloride intake is proportional to sodium 100% hydroxide consumption with correction of residual concentration of hypochlorous acid in resulting solution of glycerol dichlorohydrines, which concentration is found from the pH and redox potential values of glycerol dichlorohydrine solution. In order to convert sodium hypochlorite formed in the process into hypochlorous acid, hydrogen chloride is introduced into vessel with glycerol dichlorohydrine solution obtained, while stabilizing consumption of hydrogen chloride from pH value of resulting solution. EFFECT: enabled formation of stream of glycerol dichlorohydrines with predetermined concentration of the latter in solution and achieved essentially complete conversion of starting allyl chloride and minimum formation of side products. 1 dwg