SU1082792A1 - Process for producing perchlorovinyl resin - Google Patents

Abstract

METHOD FOR PRODUCING RESIN perhlorvinil chlorination with gaseous chlorine in PVC chlorobenzene solution in the presence of initiator and accelerator at 110115S with posleduyupschm release resin and recycling of off-gases, containing non-reacted chlorine, characterized in that, in order to increase the chlorine conversion and elimination of contaminated waste water, unreacted chlorine is absorbed by chlorobenzene at () - (- 20) C in the presence of urotropin, added in an amount of 0.01-0.1 wt.% per i chlorobenzene, followed by recycling (L absorber th e chlorine and chlorobenzene. C

Description

The invention relates to the chemical industry and to processes for the preparation of chlorinated polymers, in particular, perchlorovinyl resin, which is used for the preparation of chemically aggressive varnishes, adhesives and fibers. There are known methods for the preparation of perchlorovinyl resin by chlorinating polyvinyl chloride in an organic solvent by chlorofluoride in an organic solvent by chlorinating polyvinyl chloride in an organic solvent by chloroform in an organic solvent by chlorinating polyvinyl chloride in an organic solvent by chlorinating polyvinyl chloride ) at 100-110 ° C in the presence of initiator C 1. The process is characterized by a high consumption of chlorine, a significant part of which does not react in the chlorination reaction. Closest to the proposed technical essence is the method of obtaining perchlorovinyl resin by chlorination of polyvini chloride with chlorobenzene solution at 100-115 ° С in the presence of an initiator (or without it) and accelerator by chlorine gas. Cyclic amines or organic phosphates are used as a process accelerator. After chlorination, the perchlorovinyl resin solution in chlorobenzene is purged with nitrogen from diluted gases — chlorine and hydrogen chloride and sent to a water plant to separate the target product from the solvent, and the exhaust gases from the chlorination stage containing unprotected chlorine, hydrogen chloride and chlorobenzene impurities. recycling by treatment with an aqueous solution of alkali (NaOH or Ca (OH2). This produces wastewater contaminated with hypochlorites, alkali metal salts and chlorobenzene, which are fed to the purification L 2 J. The disadvantage of this method is the formation of a large amount of polluted wastewater (up to 10 finished products), the purification of which is associated with large energy and capital costs. In addition, the method is characterized by a low chlorine utilization rate. So, even in the presence of an accelerator - hexamine chlorine conversion does not exceed 35 wt.%. The purpose of the invention is to increase the conversion of chlorine and eliminate contamination; .1X wastewater. The goal is achieved by the fact that according to the method for producing a perchlorovinyl resin by chlorination with polyvinyl chloride chlorine gas in a solution of chlorobenzene in the presence of an initiator and accelerator at 100-IIS C, followed by separation of the resin and disposal of gases containing unreacted chlorine, unreacted chlorine, absorb benzene. - (- 20) s in the presence of urotropine added in an amount of 0.01-0.1 wt.% Based on chlorobenzene, followed by recycling of absorbed chlorine and chlorobenzene. Unreacted chlorine dissolved in chlorobenzene is desorbed from it by any known method, for example by heating the solution, and is again used for XjiopHpoBan or polyvinyl chloride. When used as an absorbent that does not contain uro additives, tropin, significant formation of benzene polychlorides is observed due to the side reaction of chlorination. This leads to an increase in the consumption of chlorine and chlorobenzene and the formation of non-utilizable by-products. The addition of urotropin in an amount of 0.010, 1 wt.% Suppresses the chlorination of chlorobenzene and allows the absorbent to be repeatedly used to trap chlorine without noticeable formation of polychlorobenzenes. Example 1. In a 1.0 l flask, 560 g of chlorobenzene, 50 g of polyvinyl chloride and 0.15 g of an accelerator, trichlorostilphosphate are charged. Then the flask is heated to 100-115 ° C and at the same time the flow of azobisisobutyronitrile initiator (0.05% by weight of polyvinyl chloride) and chlorine are switched on at a rate of 90 or 150 ml / min. Hydrogen chloride and unreacted chlorine formed during the chlorination of polyvinyl chloride enter the absorption column (i 40 mm, nozzle height 20 mm, Raschig ring nozzle 6 mm) irrigated with cooled chlorobenzene. I Chlorine saturated with chlorine flows into a stripping column (40 mm), and a 40 mm thick chlorine chloride flows through a chlorine benzene column. mm). The stripped chlorine is returned to chlorination, and chlorobenzene released from chlorine is cooled and reused

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absorption or to dissolve poly-distillation with water vapor and after vinyl chloride. moisture is analyzed in accordance with hydrogen chloride, purified by OST 6-01-37-79. chlorine and chlorobenzene impurities, after

The results of the experiments are represented by obtaining hydrochloric acid. Lena in Table. 1. For comparison, chlorination is carried out up to the table. 1 shows examples of the efficacy of the polymer / V 63 wt.%. Laziness of the process according to the known

The resulting perchlorovinyl method. In tab. 2, the indicators are given; they are separated from chlorobenzene by 10 quality of the resin.

Table 1

Table continuation

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Thus, the use of pre-salts and impurities of the chlorine-bengable method allows liquid ash.

In this case, the coefficient of utilization of hypochlorite, inorganic chlorine increases to 99%.

Claims (1)

METHOD FOR PRODUCING PERCHLOROVINYL RESIN by chlorination with gaseous chlorine of polyvinyl chloride in a solution of chlorobenzene in the presence of an initiator and an accelerator at 110115 ° С followed by separation of tar and utilization of gases containing unreacted chlorine, characterized in that, in order to increase the conversion of chlorine and chlorine and absorbed with chlorobenzene at (+10) - (- 20) ° C in the presence of urotropin added in an amount of 0.01-0.1 wt.% based on g chlorobenzene, followed by recycling absorbed wit chlorine and chlorobenzene. I 1082792 of perchlorovinyl resin by chlorination with gaseous chlorine of polyvinyl chloride in a solution of chlorobenzene in the presence of an initiator and an accelerator at 5 100-115 ° С followed by isolation of the resin and disposal of gas gases containing unreacted chlorine, unreacted chlorine is absorbed by chlorobenzene at (+10) - (- 20) ° С in the presence of urotropine added in an amount of 0.01-0.1 wt. .% calculated on chlorobenzene, followed by recycling of absorbed chlorine and chlorobenzene. Unreacted chlorine dissolved in chlorobenzene is stripped from it in any known manner, for example by heating the solution, and is again used for chlorination of polyvinyl chloride. When used as an absorbent that does not contain urotropine additives, the formation of significant amounts of benzene polychlorides is observed due to the side reaction of chlorination. This leads to an increase in the consumption of chlorine and chlorobenzene and the formation of unsuccessful (Zable by-products. The addition of urotropine in an amount of 0.010.1 wt.% Inhibits the chlorination of chlorobenzene and allows the reagent to be used repeatedly to capture chlorine without noticeable formation of polychlorobenzenes. Example 1. In a flask with a capacity of 1.0 l, 560 g of chlorobenzene, 50 g of polyvinyl chloride and 0.15 g of trichloroethyl phosphate accelerator are charged. The flask was then heated to 100-115 C ^e and simultaneously feeding the initiator include azobisisobutyronitrile (0.05% by weight of polyvinyl chloride) and chlorine at a rate of 90 or 150 ml / min. Hydrogen chloride formed during the chlorination of polyvinyl chloride _/ reagent and unreacted chlorine enter the absorption column ((6–40 mm, nozzle height 20 mm, Raschig ring nozzle / 6 mm) irrigated with chilled chlorobenzene. Chlorobenzene saturated with chlorine flows into a stripping column (“5–40 mm, nozzle height 50 mm). The stripped chlorine is returned to chlorination, and the chlorobenzene freed from chlorine is cooled and reused either for