RU2292334C1 - Method for preparing quaternary ammonium alkoxides - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of quaternary ammonium alkoxides. Method involves electrolysis of quaternary ammonium salts of the formula: [R₁-R₂-R₃-R₄-N]⁺Cl^- wherein R₁, R₂, R₃ and R₄ mean (C₁-C₄)-alkyl; R₃ and R₄ mean -CH₂-CH=CH, -CH₂CCl=CH₂, -CH₂-CH=CHCl; R₄ means benzyl taken as a solution in the concentration 40-70 weight% in dried alcohols of the formula: R-OH wherein R means (C₁-C₄)-alkyl, -CH₂-CCl=CH₂, -CH₂-CH=CHCl, benzyl, and process is carried out in two- or three-chamber electrolyzers with ion-exchange membranes at temperature 20-40°C and the current cathode density value 30-50 mA/cm² wherein the corresponding quaternary ammonium alkoxide as 1-3% of alcoholic solution is placed in the electrolyzer cathode space. Method provides simplifying synthesis of quaternary ammonium alkoxides based on exclusion for using alkaline metals or metal hydroxides and to reduce danger of the process significantly. Synthesized compounds can be used as catalysts in different reactions carrying out under interphase conditions, as reagents in the dehydrochlorination reaction of polychloroalkanes and in synthesis of ether by interaction with monohalide-derivatives.

EFFECT: improved method of synthesis.

2 tbl, 2 dwg, 5 ex

Description

The present invention relates to organic synthesis, in particular to a method for producing alkoxides of trialkylbenzyl, tetraalkyl, dialkyl dipropenyl and dialkyl-β or γ-chloropropenyl ammonium (ATABA).

This type of organic compounds can be used as catalysts in various reactions occurring under interphase conditions, as polychloroalkane dehydrochlorination reagents, and also in the synthesis of ethers by interaction with monohalo derivatives (Shavanov S.S., Tolstikov G.A. et al. Synthesis and properties of triethylbenzylammonium alkoxides. Reactivity in the reactions of cleavage and nucleophilic substitution // Journal of Organic Chemistry - 1990, - T.26, - Issue 4, - p.750-756).

A known method of producing ATABA based on the interaction of quaternary ammonium salts (HOUR) with alkali metal alkoxides obtained by the interaction of alkali metals with dried alcohols (Auth. Certificate. USSR No. 1038338, MKI C 07 C 87/30. Alkoxides and aroxides of trialkylalkyl / alkyl derivatives / ammonium as a catalyst for dehydrohalogenation of halocarbons / Shavanov S.S., Tolstikov G.A., Shutenkova T.V., Rafikov S.R. Bulletin of the Invention No. 32, 1983)

[R ₁ R ₂ R ₃ R ₄ N] ⁺ Cl ^- + RONa → [R ₁ R ₂ R ₃ R ₄ N] ⁺ OR ^- + NaCl.

The disadvantages of this method include the need to work with alkali metals, which is not safe, as well as the need to separate the resulting NaCl reaction.

Closest to the claimed, i.e. The prototype is a method for producing quaternary ammonium alkoxides by electrolysis of quaternary ammonium salts of the formula [R ₁ R ₂ R ₃ R ₄ N] ⁺ X ^- , where R ₁ R ₂ R ₃ R ₄ - may be the same or different and optionally linear or branched alkyl phenyl, benzyl group, and X ^- may represent Cl ^- , Br ^- , I ^- . The process is the electrolysis of 1-40 wt.% Solutions of [R ₁ R ₂ R ₃ R ₄ N] ⁺ X ^- in alcohols of the formula ROH, where R is C ₁ -C ₄ alkyl, placed in the cathode chamber of a two-chamber electrolyzer with an anion-exchange membrane, and an alkali metal halide or halide acid solution is placed in the anode. Electrolysis is carried out at a current density of 1-1000 mA / cm ² and a temperature of 10-45 ° C (WO 91/15615 from 10.17.1991).

The disadvantages of the prototype method include the need for isolation of an alkoxide from a mixture of this alkoxide and a quaternary ammonium salt. This is due to the fact that the alcohol solution of the quaternary ammonium salt is placed in the cathode space of a two-chamber electrolyzer with an anion-exchange membrane. At the same time, in the electric field, Cl ^- ions are transferred from the cathode chamber to the anode and their further decomposition at the anode with the formation of gaseous chlorine. Since the complete extraction of chlorine ions from the Quaternary ammonium salt and their transfer to the anode chamber of the electrolyzer is practically impossible, a mixture containing alkoxide and Quaternary ammonium salt will accumulate in the cathode chamber.

The invention solves the technical problem of simplifying the method of producing ATABA, eliminating the need to isolate alkoxide from its mixture with a quaternary ammonium salt. In addition, the possibility of implementing this method in a three-chamber electrolyzer with an updated cathodic current density (30-50 mA / cm ² ) and at a temperature of 20-40 ° C is shown.

The problem is achieved in that quaternary ammonium alkoxides are obtained by electrolysis of quaternary ammonium salts, taken in the form of 40-70 wt.% Dried alcohol solutions, in two-chamber or three-chamber electrolyzers with ion-exchange membranes at a current density of 30 ÷ 50 mA / cm ² and a temperature of 20 ÷ 40 ° C.

To prevent the formation of quaternary ammonium hydroxides in the preparation of alcohol solutions of quaternary ammonium salts, dried ROH alcohols (water content not more than 0.1%) are used, where R is alkyl C ₁ -C ₄ , -CH ₂ -CCl = CH ₂ , -CH ₂ -CH = CHCl, benzyl.

The invention consists in the following. In the anode chamber 1 of the three-chamber electrolyzer (see figure 1), separated by an anion exchange membrane A, a 1-3% alcohol solution of the corresponding HOUR is placed. A 1-3% alcohol solution of the corresponding ATABA is placed in the cathode chamber 2, separated by a cation exchange membrane K. A 40-70% (predominantly 60%) alcohol solution of HOUR is placed in the middle chamber 3. Dissociation of HOUR molecules occurs in an alcohol solution

[R ₁ R ₂ R ₃ R ₄ N] ⁺ Cl ^- → R ₁ R ₂ R ₃ R ₄ N ⁺ + Cl ^-

with the formation of cations R ₁ R ₂ R ₃ R ₄ N ⁺ and anions Cl ^-

where R ₁ R ₂ R ₃ , R ₄ is alkyl C ₁ -C ₄ ;

R ₃ R ₄ - -CH ₂ -CH = CH ₂ , -CH-CCl = CH ₂ , -CH ₂ -CH = CHCl;

R ₄ is benzyl.

In the electric field produced in the electrolytic cell by applying a voltage to the electrodes on the transfer of cations R ₁ R ₂ R ₃ R ₄ N ⁺ from the middle chamber by a cation exchange membrane into the cathode electrolysis chamber, and the anions Cl ^- through the anion exchange membrane into the anode chamber of the cell. In the cathode chamber, alcohol decomposes with the release of hydrogen gas and the formation of the corresponding anions

2ROH + 2e → H ₂ + 2RO ^-

where R is alkyl C ₁ -C ₄ , -CH-CCl = CH ₂ , -CH ₂ -CH = CHCl, benzyl, which, interacting with cations R ₁ R ₂ R ₃ R ₄ N ⁺ , lead to the formation of the corresponding alkoxide

R ₁ R ₂ R ₃ R ₄ N ⁺ + RO ^- → [R ₁ R ₂ R ₃ R ₄ N] ⁺ OR ^- .

In the anode chamber, the decomposition of chlorine anions takes place, transferred to it from the middle chamber through an anion exchange membrane

2Cl ^- -2e → Cl ₂ .

The concentration of HOUR in the middle chamber of the electrolyzer is kept constant when crystalline HOUR is added to it.

Upon receipt of ATABA in a two-chamber electrolyzer with a cation exchange membrane (see FIG. 2), the anode chamber 1 is filled with 40–70% (mainly 60%) of an alcoholic solution of HOURS. A 1 ÷ 3% solution of the corresponding ATABA is placed in the cathode chamber 2.

In the electric field, the cations R ₁ R ₂ R ₃ R ₄ N ⁺ are transferred from the anode to the cathode chamber, in which the corresponding alkoxides are formed. The process is carried out at 20 ÷ 40 ° C until the concentration of ATABA in the cathode chamber reaches 25 ÷ 30%. If it is necessary to obtain more concentrated ATABA solutions, the solvent is evaporated in vacuum at a temperature of 30 ÷ 50 ° C.

Example 1

70 ml of a 3% methanol solution [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^{- are} poured into the anode chamber of a three-chamber electrolyzer separated by an MA-40 brand anion exchange membrane. 70 ml of a 2% methanol solution [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ OCH ₃ ^{- are} poured into the cathode chamber separated by a MK-40 cation exchange membrane. 70 ml of a 60% methanol solution of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^{- are} poured into the middle chamber. During electrolysis, in order to maintain the concentration of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^- in the middle chamber, a crystalline HOUR is added to it. As electrodes, titanium plates coated with ruthenium oxide are used. The process is carried out at a temperature of 20 ° C, current strength of 0.5 A, cathodic current density of 40 mA / cm ² . After 6 hours, a 31.7% methanol alkoxide solution is obtained in the cathode chamber of the electrolyzer. The weight formed as a result of electrolysis [(C ₂ H _{5) 3} CH ₂ C ₆ H ₅ N] ⁺ OCH ₃ ^- amounts to 24.1 g, the current efficiency - 96.4%, the yield of the substance - 99.5%.

Example 2

70 ml of a 60% methanol solution [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^{- are} poured into the anode chamber of a two-chamber electrolyzer with a MK-40 cation-exchange membrane. 70 ml of a 2% methanol solution of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ OCH ₃ ^{- are} poured into the cathode chamber. During electrolysis, to maintain the concentration of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^- in the anode chamber, a crystalline HOUR is added to it. As electrodes, titanium plates coated with ruthenium oxide are used. The process is carried out at a temperature of 30 ° C, current strength of 0.5 A, cathodic current density of 40 mA / cm ² . After 6 hours, a 32.1% methanol solution of triethylbenzylammonium methoxide is obtained in the cathode chamber. The weight formed as a result of electrolysis [(C ₂ H _{5) 3} CH ₂ C ₆ H ₅ N] ⁺ OCH ₃ ^- amounts to 24.3 g, the current efficiency - 97.3%, the yield of the substance - 99.7%.

Example 3

70 ml of a 60% methanol solution [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^{- are} poured into the anode chamber of a two-chamber electrolyzer with a MK-40 cation-exchange membrane. 70 ml of a 2% methanol solution of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ OCH ₃ ^{- are} poured into the cathode chamber. During electrolysis, to maintain the concentration of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^- in the anode chamber, a crystalline HOUR is added to it. As electrodes, titanium plates coated with ruthenium oxide are used. The process is carried out at a temperature of 40 ° C for 6 hours at various cathodic current densities. The results of the experiments are presented in table 1.

Table 1 Current strength, A Current density, mA / cm ² The concentration of alkoxide,% The mass of alkoxide obtained, g Current output,% 0.3 24 19.3 13.24 88.4 0.4 32 25,2 18.69 93.6 0.5 40 30.6 24.41 97.8 0.6 48 34.5 29.15 97.3 0.7 56 36.1 31.35 89.7

From the results shown in table 1 it is seen that the current efficiency depends on the cathode current density. The maximum current efficiency is achieved at a cathodic current density of 40 mA / cm.

Example 4

70 ml of a 60% methanol solution [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^{- are} poured into the anode chamber of a two-chamber electrolyzer with a MK-40 cation-exchange membrane. 70 ml of a 2% methanol solution of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ OCH ₃ ^{- are} poured into the cathode chamber. During electrolysis, to maintain the concentration of [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] ⁺ Cl ^- in the anode chamber, a crystalline HOUR is added to it. As electrodes, titanium plates coated with ruthenium oxide are used. The process is carried out at a temperature of 25 ° C, current strength of 0.5 A, cathodic current density of 40 mA / cm ² for 6 hours.

Example 5

70 ml of a 60% methanol solution [(CH ₃ ) ₂ (CH ₂ -CH = CH ₂ ) ₂ N] ⁺ Cl ^{- are} poured into the anode chamber of a two-chamber electrolyzer with a MK-40 cation-exchange membrane. 70 ml of a 2% methanol solution of [(CH ₃ ) ₂ (CH ₂ —CH = CH ₂ ) ₂ N] ⁺ OCH ₃ ^{- are} poured into the cathode chamber. During electrolysis, in order to maintain the concentration of [(CH ₃ ) ₂ (CH ₂ —CH = CH ₂ ) ₂ N] ⁺ Cl ^- in the anode chamber, a crystalline HOUR is added to it. As electrodes, titanium plates coated with ruthenium oxide are used. The process is carried out at a temperature of 25 ° C, current strength of 0.5 A, cathodic current density of 40 mA / cm ² for 6 hours. In addition to these, experiments are conducted with alcohol solutions of other quaternary ammonium salts. The results of the experiments and the structure of the obtained alkoxides are shown in table 2.

table 2 No. p / p Name of reagents The output stream,% The yield on the substance,% Conc. ATABA,% ATAB structure Quaternary ammonium salts Alcohols one [(CH ₃ ) ₃ CH ₂ C ₆ H ₅ N] Cl CH ₃ OH 97.3 99.7 32.1 [(CH ₃ ) ₃ CH ₂ C ₆ H ₅ N] OCH ₃ 2 [(CH ₃ ) ₄ N] Cl CH ₃ OH 92.0 98.5 27.3 [(CH ₃ ) ₄ N] OCH ₃ 3 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl CH ₃ OH 86.2 98.3 26.7 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] JCH ₃ four [(C ₂ H ₅ ) ₃ C ₃ H ₅ N] Cl CH ₃ OH 90,4 99,4 29.1 [(C ₂ H ₅ ) ₃ C ₃ H ₅ N] OCH ₃ 5 [(CH ₃ ) ₂ (CH ₂ —CH = CH ₂ ) ₂ N] Cl CH ₃ OH 85,2 98.0 24.2 [(CH ₃ ) ₂ (CH ₂ —CH = CH ₂ ) ₂ N] OCH ₃ 6 [(C ₄ H ₉ ) ₄ N] Cl CH ₃ OH 91.2 99.1 28.3 [(C ₄ H ₉ ) ₄ N] OCH ₃ 7 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl C ₂ H ₅ OH 88.2 99,4 30.1 [C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OS ₂ H ₅ 8 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl C ₄ H ₉ OH 87.3 99.6 26,4 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OS ₄ H ₉ 9 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl C ₃ H ₆ OH 85.7 99.0 25.6 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OS ₃ H ₆ 10 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl i-C ₃ H ₇ OH 86.4 98.0 23.9 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OS ₃ H ₇ eleven [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl C ₆ H ₅ CH ₂ OH 84.1 99,2 24.5 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OCH ₂ C ₆ H ₅ 12 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl CH ₂ = CHCl-CH ₂ OH 91.2 98.8 25.3 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OCH ₂ —CHCl = CH ₂ 13 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] Cl ClCH ₂ = CH-CH ₂ OH 93,4 99.5 29.1 [(C ₂ H ₅ ) ₃ CH ₂ C ₆ H ₅ N] OCH ₂ —CH = CHCl

The results shown in table 2 show that the structure of the obtained alkoxides is determined by the structure of the quaternary ammonium salt and alcohol. The electrolysis process proceeds with sufficiently high current and material yields. The concentration of the resulting alcohol solutions of alkoxides ranges from 23.9 to 32.1%.

Using the proposed method for producing quaternary ammonium alkoxides compared with existing has the following advantages:

a) eliminating the need for separation of the alkoxide from the resulting mixture of ATABA and Quaternary ammonium salt;

b) the absence of NaCl in the target product eliminates the need to isolate this salt from it;

c) elimination of the need to work with alkali metals, which increases the safety and environmental friendliness of the process.

Claims (1)

The method of producing quaternary ammonium alkoxides by electrolysis of quaternary ammonium salts in alcohol solutions at a temperature of 20 ÷ 40 ° C, at a cathodic current density of 30 ÷ 50 mA / cm ² , characterized in that the electrolysis of quaternary ammonium salts of the formula [R ₁ R ₂ R ₃ R ₄ N] ⁺ Cl ^- , where R ₁ , R ₂ , R ₃ , R ₄ - alkylC ₁ -C ₄ , R ₃ , R ₄ - -CH ₂ -CH = CH ₂ , -CH ₂ -CCl = CH ₂ , -CH ₂ -CH = CHCl, R ₄ - benzyl taken in the form of 40 ÷ 70 wt.% Solutions in dried alcohols of the formula ROH, where R is alkylC ₁ -C ₄ , -CH ₂ -CCl = CH ₂ , -CH ₂ -CH = CHCl, benzyl, into a two- or three-chamber electrolysis cells with ion exchange membranes , While in the cathode compartment electrolytic cell was placed 1-3% alcoholic solution of the corresponding quaternary ammonium alkoxide.

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