RU2167141C1 - Method of preparing vinylidene chloride - Google Patents

Abstract

FIELD: chemical industry. SUBSTANCE: described is method of preparing vinylidene chloride by dehydrochlorination of 1,1,2-trichloroethane in the presence of catalyst and alcoholic additive. Process is carried out at temperatures from 15 to 20 C in the presence of catalyst such as diethylallyl-γ-chloropropenylammonium chloride or di-β-oxyethyl allyl-γ-chloropropenylammonium chloride and alcoholic additive of formula ROH wherein R is C₂-C₄ alkyl, ClCH = CH-CH₂OH. Catalyst to alcoholic additive molar ratio is 1:3-1, 1.2-trichloroethane is subjected to aqueous alkali dehydrochlorination in mixture of clarified perchlorovinyl production waste, and vinylidene chloride, trichloroethylene and 1,1,1,2- tetrachloroethane are subsequently recovered from organic phase to derive vinylidene chloride from perchlorovinyl production waste. EFFECT: more efficient preparation method. 2 ex

Description

 The invention relates to organic synthesis, in particular to a method for the production of vinylidene chloride by the disposal of wastes from the production of chlorinated polyvinyl chloride (perchlorovinyl).

A known method of producing vinylidene chloride by dehydrochlorination of individually 1,1,2-trichloroethane with a 6-24% aqueous solution of an alkali metal hydroxide at a temperature of 90 ^o C in the presence of an alkylbenzylammonium chloride catalyst of the formula / R ₁ R ₁ R ₂ C ₆ H ₅ CH ₂ N ⁺ / ^- Cl, where R ₁ -CH ₃ or HOCH ₂ -CH ₂ , R ₂ -C ₁₀ -C ₁₈ , vinylidene chloride is formed with a yield of up to 85% / Japanese patent N 164416, 1961 /.

 The disadvantage of this method is the reaction at high temperature and a low yield of the target product.

 The closest to the claimed invention technical solution for the totality of features is a method for producing vinylidene chloride by water-alkaline dehydrochlorination of 1,1,2-trichloroethane in the presence of a catalyst and an alcohol additive / Shavanov S.S. and others. "On the catalysis of liquid-phase dehydrochlorination of 1,1,2-trichloroethane." Housing and communal services, N 1, 1987, p. 150-153 /.

Water-alkaline dehydrochlorination of 1,1,2-trichloroethane is carried out by the action of 40% NaOH at its molar ratio to trichloroethane 1: 1.3 at a temperature of 25 ^o C in the presence of catalysts, which are used triethylbenzylammonium alkoxides or a triethylbenzylammonium chloride catalyst system: benzyl alcohol.

 The authors showed that triethylbenzylammonium benzylate or the triethylbenzylammonium chloride: benzyl alcohol system has the highest catalytic activity.

 The disadvantage of this method is the use of only pure, expensive 1,1,2-trichloroethane, as well as the need to use difficult to obtain triethylamine, benzyl alcohol and benzyl chloride to obtain catalysts.

 The objective of the invention is to develop a method for producing vinylidene chloride from waste products of chlorinated polyvinyl chloride.

 Chlorination of polyvinyl chloride in 1,2-dichloroethane produces a significant amount of 1,1,2-trichloroethane. After rectification, bottoms (waste products of perchlorovinyl) can be used to produce carbon tetrachloride / Oshin L.A. "Industrial organochlorine products." M .: Chemistry, 1978, p. 577 /.

 However, according to the Montreal Agreement for the Protection of the Earth's Azone Layer, carbon tetrachloride is not recommended for industrial use.

 Problems of utilization and processing of waste products for the production of organochlorine products is one of the most urgent problems of the chemical industry.

When using the invention, the technical result can be obtained:
- utilization of perchlorovinyl production waste;
- the possibility of obtaining relatively inexpensive vinylidene chloride;
- it is possible to separate the remaining components of the organochlorine wastes of perchlorovinyl production and return them to the technological cycle;
- the exclusion of the possibility of the formation of explosive dichloroacetylene;
- the availability of raw materials for the manufacture of the catalyst.

The specified technical result in the implementation of the invention is achieved by the fact that in the known method for producing vinylidene chloride by water-alkaline dehydrochlorination of 1,1,2-trichloroethane in the presence of a catalyst and an alcohol additive, the peculiarity lies in the fact that water-alkaline dehydrochlorination at a temperature of 15-20 ^o C in the presence of a catalyst, which is used diethylallyl-γ-chloropropenylammonium chloride or di-β-hydroxyethylallyl-γ-chloropropenylammonium chloride and an alcohol additive of the formula ROH, where R is alkyl C ₂ -C ₄ , ClCH = CH-CH ₂ OH p With a molar ratio of catalyst to alcohol additive of 1: 3-1, 1,1,2-trichloroethane is subjected to a mixture of clarified waste products of perchlorovinyl with further isolation of vinylidene chloride, trichlorethylene and 1,1,1,2-tetrachloroethane from the organic phase.

 The method is as follows.

In the reactor, equipped with a thermostatic device, a reflux condenser, an agitator, a thermometer and a separatory funnel, the calculated amount of bottoms clarified by distillation containing (wt%) 1,1,2-trichloroethane - 80-90, 1,1,1,2- is placed tetrachloroethane - 3-8, 1,1,2,2-tetrachloroethane -10-12. To this mixture, 0.8-1.0 wt.% To 1,1,2-trichloroethane, a diethyl-γ-chloropropenylammonium chloride catalyst or di-β-hydroxyethylallyl-γ-chloropropenylammonium chloride and 1-3 moles of an alcoholic additive of the formula ROH are added, where R is alkyl C ₂ -C ₄ , ClCH = CH-CH ₂ OH. With stirring and a temperature of 15-20 ^o C add 1.3 mol to 1,1,2-trichloroethane 28-30% aqueous NaOH, after which the mixture is stirred for another 0.5 hours.

Desalted water was added to the reactor to dissolve the precipitated NaCl, and the reaction mixture was placed in a separatory funnel. The organic layer is separated, purged with nitrogen and distilled with a reflux condenser at a temperature not exceeding 65 ^o C, a fraction boiling at a temperature of 32 ^o C is selected. Vinylidene chloride is obtained with a purity of not less than 99%, the conversion of 1,1,2-trichloroethane 93-95%. The bottoms containing trichlorethylene and 1,1,1,2-tetrachloroethane are rectified to give pure trichlorethylene.

 The method is illustrated by examples.

 Example 1. In a reactor equipped with a mixing device, a reflux condenser, a separatory funnel, a thermometer and a thermostatic device, 160 g of wastes of perchlorovinyl production of the following composition are placed, wt%: 1,1,2-trichloroethane - 80; 1,1,1,2-tetrachloroethane - 12; 1,1,2,2-tetrachloroethane - 8.

 To this product mixture is added 1 g (0.8 wt.% To 1,1,2-trichloroethane) or diethylallyl-γ-chloropropenylammonium chloride in the form of a 50% aqueous solution and 1.6 g of butyl alcohol (molar ratio of catalyst: alcohol is 1: 3).

With stirring and a temperature of 15-20 ^o C, the mixture is purged with nitrogen and 50 g of NaOH taken in the form of a 30% aqueous solution are added (molar ratio of 1,1,2-trichloroethane: NaOH is 1: 1.3).

 Upon completion of the addition of NaOH (15 min), the reaction mass at this temperature is stirred for another 1 hour, desalted water is added to dissolve the precipitated NaCl, and the reaction mixture is placed in a separatory funnel.

The organic layer is separated, purged and distilled with a reflux condenser, selecting a fraction with a boiling point of 32 ^o C.

 Obtain 89 g of vinylidene chloride (yield 96%), 9 g of trichlorethylene, 18 g of 1,1,1,2-tetrachloroethane.

 Example 2. In the conditions of example 1, taken 160 g of waste production of perchlorovinyl composition, wt. %: 1,1,2-trichloroethane - 90, 1,1,2,2-tetrachloroethane - 7%, 1,1,1,2-tetrachloroethane - 3.

 To this mixture was added 1.4 g of di-β-hydroxyethylallyl-γ-chloropropenylammonium chloride as a 50% aqueous solution and 0.8 g of chloropropenyl alcohol (molar ratio of catalyst: alcohol is 1: 1). Dehydrochlorination is carried out with 28% aqueous NaOH.

 99 g of vinylidene chloride (yield 95%), 8 g of trichlorethylene and 4 g of 1,1,2,2-tetrachloroethane are obtained.

The advantages of the proposed method:
- utilization of perchlorovinyl production waste;
- the possibility of obtaining not expensive vinylidene chloride;
- providing the possibility of separation of the remaining components of organochlorine waste production of perchlorovinyl;
- the method is technological and safe, since the possibility of the formation of explosive dichloroacetylene is excluded;
- the used catalysts are obtained from available raw materials: allyl chloride and diethanolamine.

Claims (1)

A method of producing vinylidene chloride by water-alkaline dehydrochlorination of 1,1,2-trichloroethane in the presence of a catalyst and an alcohol additive, characterized in that the water-alkaline dehydrochlorination at a temperature of 15-20 ^° C in the presence of diethylallyl-γ-chloropropenylammonium chloride or di- β-hydroxyethylallyl-γ-chloropropenylammonium chloride and an alcohol additive of the formula ROH, where R is alkyl C ₂ -C ₄ , ClCH = CH-CH ₂ OH, with a molar ratio of catalyst to alcohol additive equal to 1: 3-1, 1 1,2-trichloroethane in a mixture of clarified industrial waste production of perchlorovinyl with further isolation of vinylidene chloride, trichlorethylene and 1,1,1,2-tetrachloroethane from the organic phase.