CS232535B1 - Process for preparing alkylaryl ethers - Google Patents

Abstract

The invention relates to a process for the preparation of alkylaryl ethers in a two-phase liquid system f in the presence of a quaternary anonium catalyst. The present invention provides the use of quaternary ammonium compounds having a maximum of 10 carbon atoms.

Description

The invention relates to the preparation of alkyl aryl ethers in a two-phase liquid system in the presence of quaternary ammonium compounds.

The two-phase arrangement of the preparation of alkylaryl ethers from an aromatic halogen compound containing reactive halogen bound to the aromatic ring, most commonly chlorine, by reaction with the corresponding alcohol in the presence of an aqueous sodium hydroxide solution is possible according to the literature and patent literature in the presence of quaternary ammonium salts. nitrogen atom sum of all carbon atoms greater than 10 (German Pat.

634,419). The optimum size of the quaternary ammonium cation in the biphasic nucleophilic reactions catalysed by these cations is the quaternary ammonium cation having a total carbon number of 16 to 40. When quaternary quaternary ammonium cations are used in the two-phase production of alkylaryl ethers Ammonium compounds having a carbon number in the cation greater than 10, are used to achieve a catalytic effect and as a carrier of their catalytic activity, the highly lipophilic character of these cations.

It has now been found that the preparation of two-phase alkyl aryl ethers from an aromatic compound containing an active halogen atom, most often chlorine, by reacting it with the appropriate alcohol in the presence of aqueous sodium or potassium hydroxide under the catalytic action of quaternary ammonium compounds wherein the catalyst used is a quaternary ammonium compound of the general formula R - N ⁺ (CH3). X ', wherein the amine X - may be a halogen anion, most commonly chlorine, a hydroxyl group, an arylsulfonic group, wherein aryl is phenyl or -olyl, or further an alkylsulfonyl group R 6a ', wherein H * is C 1 to C 7 -tolyl; and wherein the substituent R in the quaternary ammonium cation RN (CH3) is an alkyl or benzyl group having a maximum number of carbon atoms of 7.

The catalytic activity of the quaternary ammonium compounds used in the production of the alkyl aryl ethers of the invention is based on the easier formation of ionic pairs of these compounds with the alcoholate anions entering the reaction because the low bulk alkyltrimethylammonium cations are harder Lewia acids than previously used bulky quaternary ammonium cations. the alcoholate anions of the ion pair more easily. With the use of quaternary ammonium compounds of the above type RN ⁺ (CH 2) 4 X ", due to the easier formation of ion pairs from their cations with the alcoholate anion, the two-phase preparation of alkylarylethers results in higher conversion of the aromatic halogen compound and reducing its residual content in the crude product. , which would interfere with the isolation and further processing of this product, up to 1/9 compared to the previous procedures. Other advantages of the process according to the invention include low emulsification capacity of these low-volume quaternary ammonium compounds, low molecular weight, non-foaming and low cost.

In order to further illustrate the invention, the following examples are provided:

He did

To a mixture of 157 g of p-nitrochlorobenzene, 80 g of ethyl alcohol and 18 g of trimethylbenzylammonium chloride at 70-80 ° C, 240 g of 90% by weight aqueous sodium hydroxide solution are added dropwise over a period of 2.9 hours, and the mixture is maintained at 89 for 4 hours. Deň: 32 ° C. 7% of unreacted p-nitrochlorobenzene was found.

Example 2

To a mixture of 197 g of o-nitrochlorobenzene, 132 g of 2-methoxyethanol and 20 g of trimethylbenzylammonium chloride ae at 89 [deg.] C., 240 g of a 90% by weight aqueous sodium hydroxide solution is added dropwise over 2.9 hours. Deň: 32 ° C.

0.9% by weight of unreacted p-nitrochlorobenzene was found in the reaction mixture.

Example 3

Listed for comparison.

The reaction was carried out as in Example 1, but using 20 g of triethylbenzylammonium chloride catalyst. 2.5% by weight of unreacted p-nitrochlorobenzene found in the reaction mixture.

p

Example 4 »Presented for comparison.

The reaction is carried out as in Example 1, but trimethyloctadecylammonium metosulfate in an amount of 25 g is used as catalyst. 2.5% by weight of unreacted p-nitro-chlorobenzene is found in the reaction mixture.

Claims (1)

SUBJECT OF THE INVENTION A process for the preparation of biphasic alkyl aryl ethers from an aromatic compound containing an active halogen atom, most commonly chlorine, by reacting it with an appropriate alcohol in the presence of an aqueous solution of alkaline sodium or potassium hydroxide under the catalytic action of quaternary ammonium compounds. -N + CCH 2 X, wherein R represents an alkyl or aralkyl group having a maximum number of carbon atoms of 7 and wherein X ^- is a halogen anion, most commonly chlorine, a hydroxyl group, an arylsulfonic group, wherein aryl is phenyl or 4-tolyl, an alkylsulfate group Α'οεο ^ “, where R'represents group C ₍ up to C ?.