CS246328B1 - Process for preparing dichloro- (2,2) paracyclophane - Google Patents

Abstract

The process for producing dichloro-(2,2)paracyclophane proceeds in such a way that an aqueous solution of a quaternary ammonium base of the general formula I is decomposed at an elevated temperature of 40 to 140 °C, preferably 50 to 95 °C, in a reaction medium formed by a mixture of an inert hydrocarbon solvent and dimethyl sulfoxide. The inert hydrocarbon solvent is aromatic hydrocarbons or benzene, toluene or xylene.

Description

The present invention relates to a process for the preparation of dichloro- (2,2) paracyclophan. Dichl-or- (2,2) paracyclophan is a known compound of formula.

used to prepare the polydichloro-p-xylylene ipolymer.

Processes for the preparation of dichloro- (2,2) paracyclophan based on the chlorination (2,2) of paracyclophan are known (U.S. Pat. Nos. 3,221,068, 3,288,728, 3,342,739).

A disadvantage of the above processes for the preparation of dichloro- (2,2) paracyclophane is that they require (2,2-para-cyclophanes) as a starting compound, a compound which is difficult to access and costly. is the fact that the reaction product resulting from the chlorination of (2,2) paracyclophane contains, in addition to the unreacted starting material, a dichloro derivative with chlorine atoms attached to one aromatic ring and chloro derivatives with more than two chlorine atoms per molecule. for further use, to produce a well-defined polymer, said additives are undesirable and must be removed, for example, by rectification under reduced pressure.

The above-mentioned drawbacks of the preparation of dichloro- (2,2) paracyclophan are solved by the process according to the invention, wherein the quaternary ammonium base of the formula I

Cl kde

R is the same or different alkyl having 1 to 12 carbons, decomposes at a temperature of 40 to 140 ° C, preferably 50 to 95 ^° C in a reaction system consisting of an inert hydrocarbon solvent and dimethylsulfoxide. According to the invention, the inert hydrocarbon solvent may be, for example, aromatic hydrocarbons benzene, toluene and xylene. The alkyl radical R according to the invention is preferably methyl or ethyl.

The starting quaternary ammonium base is prepared in a known manner from the quaternary ammonium salt II

where

R is the same or different C 1 -C 12 alkyl and X is chlorine, bromine or iodine, by treatment with silver oxide or by treatment with a strongly basic anion exchange resin.

The advantage of the process according to the invention is that the resulting dichloro- (2,2) paracyclophan, in 85% by weight, has a precisely defined structure characterized by the presence of only 1 chlorine atom on each benzene nucleus and hence the polymer prepared from this substituted paracyclophan precisely defined structure and properties. The process according to the invention is best illustrated in the following example.

Example

A 4 1 solution of toluene were added 215.6 g I _(R-CH3) in 500 ml water and 1000 ml of dimethyl sulfoxide. The resulting mixture was stirred at 60 ° C for 8 hours and at 90 ° C for a further 8 hours. After cooling, the phases are separated, the organic phase is washed with water, filtered and evaporated to dryness.

Yield 117.7 g of dichloro- (2,2) paracyclophan, i.e. 85.0 wt.

Claims (5)

1. A process for producing dichloro- (2,2jparacyklofanu wherein the aqueous solution of quaternary aimoniové base of general formula I ¹ Cl · ^C H (R) ₃ Oli decomposes at an elevated temperature of 40 to 140 T, preferably 50 to 95 ° C, in a reaction medium consisting of a mixture of an inert hydrocarbon solvent and dimethyl sulfoxide. 2. A process according to claim 1, wherein the inert hydrocarbon solvent is aromatic hydrocarbons. 3. The process of claim 1 wherein the hydrocarbon solvent is benzene. 4. The process of claim 1 wherein the hydrocarbon solvent is toluene. 5. The process of claim 1 wherein the hydrocarbon solvent is xylene.