RU2025145C1 - Method of detoxication of chloroarsine-containing organic toxins - Google Patents

Abstract

FIELD: technology of toxin detoxication, arsenic-containing toxins. SUBSTANCE: method involves interaction of chloroarsine-containing organic toxins with liquid alkanols taken at excess quantity of stoichiometry. Interaction is carried out in the presence of ammonia at reaction medium pH 7.5-8. Liquid alkalnols with hydrocarbon radical C₁-C₅ are used as a source of liquid alkanols at 3-6-fold excess of stoichiometry. EFFECT: increased effectiveness of detoxification. 2 cl

Description

 The invention relates to the technology of detoxification of arsenic-containing poisonous substances (OV) and can be used to convert chemical weapons into products used in the national economy, as well as in other areas of technology using organo-arsenic compounds as starting products, for example, in semiconductor technology.

 As is known, organo-arsenic compounds such as ethyldichloroarasin, methyldichlorarsin, β-chlorovinyl dichlorarsin (α-lewisite), bis- (β-chlorovinyl) chlorarsin (β-lewisite) were used as skin irritants. These compounds related to personnel agents are subject to liquidation by decision of the International Chemical Weapons Convention.

 Known methods of detoxification of chloroarsine-containing OM, based on their interaction with various solid and liquid chemicals. As solid reagents were proposed calcium hydroxide, sodium sulfide.

 The disadvantages of these methods are the duration of the process when using sodium sulfide, as well as the formation and over-accumulation of solid waste washed out by water in the event that concrete waste is buried in the ground. All this makes these methods practically inapplicable.

 For the detoxification of lewisite, hydrogen peroxide was used, which converts lewisite into low-toxic chlorovinyl and bis (chlorovinyl) arsenic acids. However, the safety of such a process is sharply reduced due to the explosiveness of hydrogen peroxide, which is unacceptable during the elimination of toxic substances, since a threat of chemical contamination of the environment is created.

 The described methods relate to liquid-phase methods for treating lewisite.

 The closest in technical essence to the proposed method is a method of detoxification of lewisite by treating it with a liquid hydroxyl-containing substance - sodium hydroxide to obtain less toxic products. However, in the process of such processing significant resinification occurs, which complicates the unloading and further processing of mineralization products, leads to the formation of non-recyclable solid waste to be disposed of.

 The purpose of the invention is to simplify the process and reduce the cost of production.

This is achieved by the fact that in the method of detoxification of chloroarsin-containing organic OM, including their treatment with a chemical reagent and isolation of reaction products, liquid alkanols are used as a chemical reagent in an excess quantity with respect to stoichiometry, the treatment is carried out in the presence of ammonia at a pH of 7.5 - 8, and the reaction products are isolated by filtration and distillation. As liquid alkanols, liquid alkanols with a C ₁ -C ₅ hydrocarbon radical are used in a 3-6-fold excess from stoichiometry.

 The method differs from the prototype in the use of liquid alkanols as OM detoxicants and the process under typical conditions (pH) due to the presence of ammonia. With the proposed method, the corresponding organochlorine alkoxides of arsenic are formed, for example, arsenic chlorovinyl dialkoxides, which are significantly less toxic than lewisite and other OM, which do not have a skin-boiling effect and must be stored for a long time.

 With the known method, the mineralization reaction proceeds to the formation of arsenic polysulfides with a high content of vinyl chloride groups, which are subjected to significant resinification, are difficult to isolate, practically unreusable, and must be buried.

 An essential feature of the proposed method is the condition for carrying out the process in the presence of ammonia, which is an acceptor of the resulting hydrogen chloride, which binds the chlorine atom most reactive in organic matter in the As-Cl bond.

 Ammonia is added in an amount that determines the pH of the reaction medium is 7.5-8.

 At pH lower than 7.5, an incomplete conversion occurs, i.e. complete separation of active chlorine from arsenic does not occur, and at pH> 8 the formation of polymer compounds is possible, which are difficult to further processing and isolation.

The starting liquid alkanols, preferably C ₁ -C ₅ alkanols (methanol, isopentanol, ethanol, isopropanol, sec-butanol), are used in amounts significantly higher than stoichiometric, which is explained by the use of alkanols not only as reagents, but also as a reaction medium.

 When detoxifying α-lewisite, namely β-chlorovinyl dichlorarsin, alkanols are used in a 3-6-fold excess from stoichiometry, while detoxifying β-lewisite (bis-chlorovinylchloro chlorine), alkanols are used in the same ratio. As for other OM of a similar structure, also containing reaction chlorine (ethyldichloroarsin, methyldichloroarsin), it is also preferable to use the same ratio of reagents when detoxifying them. In the case of a reaction with smaller amounts of alkanols (less than 3-fold excess), the viscosity of the resulting mixture of the starting material with ammonium chloride increases, and in the case of very strong dilution (more than 6-fold excess of alkanol), the number of processed solutions becomes large, which leads to excessive reagent costs and energy.

 The substituted arsenic alkoxides obtained in the course of the reaction, in particular, chlorovinyl dialkoxides obtained from α-lewisite, are easily isolated by filtration, washing, and distillation of the solvent in the form of low toxic products compared to lewisite, which are used as intermediates in the production of semiconductor materials.

 PRI me R 1. Detoxification of α-lewisite using methanol.

 Methanol (19.2 g) was added to pure α-lewisite (20.7 g). Then, gaseous ammonia is bubbled through a solution of lewisite in methanol to pH 7.5 - 8. The precipitate is filtered off and washed on the filter with three equal portions of methanol (16 g each). The resulting solution of chlorvinyl dimethoxyarsine in methanol was placed in a 0.2 L flask and methanol was distilled off. The resulting product is analyzed and used in the future, distilled methanol is used for the processing of lewisite. Ammonium chloride is stored. The product yield is 86-88%.

 PRI me p 2. Detoxification of β-lewisite with ethanol.

 Ethanol (0.4 mol) was added to β-lewisite (0.1 mol). Ammonia gas was passed through a solution of bis (β-chlorovinyl) chloroarsine in ethanol to pH 7.5-8. The precipitate of ammonium chloride is filtered off and washed on the filter with three equal portions of ethanol (0.5 mol). The resulting solution of bis-β-chlorovinyl ethoxyarsine in ethanol was placed in a flask (0.2 L) and ethanol was distilled off. Product yield 85%. Distilled ethanol is used for the processing of lewisite.

 PRI me R 3. Detoxification of lewisite using isoamyl alcohol.

 To 10.5 g of lewisite (β-chlorovinyl dichlorarsin), 26.4 g of isoamyl alcohol are added. Ammonia gas was passed through a solution of β-chlorovinyl dichloroarsin in isoamyl alcohol to a pH of 7.5-8. The precipitate of ammonium chloride is filtered off and washed on the filter with three portions of alcohol (43.0 g each). The resulting solution was placed in a 0.2 L flask and the alcohol was distilled off. Product yield 80% of the calculated amount.

 Chlorvinyl dialkoxides resulting from detoxification are low toxic compared to lewisite and are used in the manufacture of semiconductor materials.

Claims (2)

 1. METHOD FOR DETOXICATION OF CHLORORAIN-CONTAINING ORGANIC POISONING SUBSTANCES, including their treatment with a chemical reagent and isolation of reaction products, characterized in that liquid alkanols are used as a chemical reagent in an excess quantity with respect to stoichiometry, the treatment is carried out in the presence of ammonia at pH 7 of the reaction medium - 8, and the reaction products are isolated by filtration and distillation. 2. The method according to claim 1, characterized in that liquid alkanols with a C ₁ - C ₅ hydrocarbon radical in a 3-6-fold excess from stoichiometry are used as liquid alkanols.