JPH03206056A - Production of dichloro-(2,2)-paracyclophane - Google Patents

Abstract

PURPOSE:To obtain the subject compound by using p-methylbenzyl trimethylammonium chloride as a raw material, selectively chlorinating to obtain a monochlorine-substituted substance of benzene nucleus, making said substance to quaternary ammonium hydroxide and subjecting to Hoffman elimination. CONSTITUTION:A quaternary ammonium salt, namely p-methylbenzyl trimethylammonium chloride is chlorinated preferably with chlorine gas to obtain monochloro-p-methylbenzyl trimethylammonium chloride. Subsequently the resultant compound is made to quaternary ammonium hydroxide and then subjected to Hoffman elimination reaction to afford the aimed dichloro-(2,2)- paracyclophane. By said method, a monochlorine-substituted substance is more readily and selectively obtained, therefore a low cost and a high purity are attained. A resultant compound is useful as an intermediate of a production of polydichloro paraxylylene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention relates to the following structural formula CI! This invention relates to a method for manufacturing a dichloro(2.2) one-nozo Lasik mouth fan represented by CI. This compound is a substance known as an intermediate compound in the production of polydichloro...raxylylene resin. This resin is formed as a film on the surface of the material by vacuum evaporation, and has excellent electrical properties and high-temperature properties. It is widely used for coating electronic components such as semiconductors and parts for space equipment.

This chloro(212)-18 laciclophane can be produced by direct chlorination of (2.2) cyclophane or by 2(5) monochlorop-methylbennorchloride D, (2 .2) Like mono-paracyclophane, it is produced by Hofmann elimination reaction via quaternary ammonium salt and quaternary ammonium hydroxide (Japanese Patent Application Laid-open No. 6
3-93740, JP-A-64-45322, etc.). The starting material for this latter production method is 2
(5) Monochloro p-methylbenzyl chloride is p-
It is produced by chlorinating methylbenzyl chloride or 2-chlorop-xylene.

Problems to be Solved by the Invention (2.2) The direct chlorination method of valacyclophane has a good yield, but the alpha chlorine substituted product deteriorates the performance of polymonochloroparaxylylene resin, which is the polymerization product. It is difficult to eliminate or eliminate by-products.

Problems with the latter method via Hoffmann elimination reaction +7)
- Tsuha, 2 (5) Production of monochloro p-methylbenol chloride. As mentioned above, there are two routes for this production (4) and ω), but the production is complicated in either method, and it is difficult to selectively obtain only monochlorinated benzene nuclei through the reaction. However, these separations and purifications are difficult to achieve, and as a result, inexpensive and highly pure dichloro(2.2) This is one of the reasons why mouth fans do not exist on the market.

Another problem is the yield problem associated with the Hofmann elimination reaction, and various proposals have been made to solve this problem (see the above-mentioned published patent application).

An object of the present invention is to solve the first problem. That is, we provide a method for easily and selectively obtaining a monochlorine substituted product, and as a result, we have provided a method for obtaining a monochlorine substituted product easily and selectively, and as a result, we have provided a method for obtaining a monochlorine substituted product at low cost and with good purity.
) The aim is to make it possible to manufacture paracyclophane.

Means for Solving the Problem As a result of continuing research to solve this problem, the present inventor chlorinated a quaternary ammonium salt as shown in the following reaction formula, which is different from the reaction route in 1. It was found that a monochlorine-substituted benzene nucleus was produced in a particularly selective manner. In this chlorination of quaternary ammonium salt, p
-Unlike the chlorination of methylbenol chloride or 2-chloro-p-xylene, it was a surprising discovery that only the monochlorine-substituted benzene nucleus was selectively produced by simply blowing chlorine gas into the aqueous solution. there were.

This quaternary ammonium salt, i.e., p-methylbenzyltrimethylammonium chloride, is generally produced by blowing trimethylamine into a solution of p-methylbenzyl chloride such as ether, and causing a reaction; however, an aqueous solution of trimethylamine is used. The method of making it is easy to operate. The two react simply by mixing and stirring, and when the reaction is complete, a homogeneous liquid forms. It generates heat, so cool it down depending on the situation. The reaction proceeds even at room temperature. Next, chlorine gas is introduced into this reaction solution while stirring.

The internal temperature rises due to the heat of reaction, so cool it appropriately.

The reaction temperature is not particularly limited, but if it is too high, the decomposition reaction described below will occur and the yield will decrease, and if it is too low, a precipitate will form, which will hinder stirring, so a range of 60 to 0°C is preferable. .

The progress of the reaction can be monitored by gas chromatography (hereinafter referred to as GC).
) can be tracked through analysis, etc. This quaternary ammonium salt decomposes as shown in the formula below when the temperature is high, so this can be used to determine the progress of the reaction. When p-methyl-benzyl chloride is no longer detected by GC analysis, stop blowing chlorine. Excess chlorine should be removed as much as possible by blowing inert gas such as nitrogen.

Next, dioxane and caustic alkali are added to this solution and heated to perform a Hofmann elimination reaction. If a reducing agent such as sodium borohydride (SBH) is added before this Hofmann elimination reaction, the coloration of the product can be reduced.

EXAMPLES Examples of the present invention will be shown below, but these are merely to illustrate specific examples of the present invention, and it goes without saying that the present invention is not limited thereto.

Example 1 p-Methylben sol chloride 14 and 30% trimethylamine aqueous solution 241 were stirred while cooling with water. When the solution became uniform and transparent, chlorine gas was blown into the solution to perform a reaction. The internal temperature rose due to heat generation, but was prevented from rising above 20°C.

The end point of the reaction was defined as the point at which the peak of p-methylbe/zyl chloride was no longer detected by GC analysis.

After that, nitrogen was blown in to drive out excess chlorine, and 160 m
/ of dioxane was added. A solution of 38 g of 85% potassium hydroxide/34 mt of water was added dropwise to this while stirring while keeping the internal temperature below 40°C, and then SBH (12% sodium borohydride, 40% sodium hydroxide aqueous solution, same hereinafter) 2 ml was added. After that, it was heated at 80℃ for about 2 hours and 30 minutes.
The reaction was continued at that temperature for 40 hours. The reaction product was poured into water, and the precipitate was collected, washed, and dried. The precipitate is 70ml of toluene! The mixture was dissolved by heating, insoluble matter was removed, and toluene was distilled off to obtain dichloro(2.2)-noguracyclonoane.

(2,2) monozoraciclophane and trichlorine substituted products or higher were not detected by GC analysis or were negligible (the same applies to the following examples).
.

Crude product yield 12.3.9 Yield 89.1% Insoluble matter 1.7.9 Product yield 10.2! i Yield 73.9% Example 2 14 J of p-methylbenzyl chloride and 48 g of a 15% aqueous trimethylamine solution were mixed with stirring.

When the solution became homogeneous and transparent, chlorine gas was blown into the solution while cooling the solution to keep the internal temperature below 5° C. to carry out a reaction. During the process, a precipitate formed and the stirring condition worsened, so another 10 ml of water was added. After confirming the completion of the reaction by GC analysis, excess chlorine was removed by blowing in nitrogen. Add 160 ml of dioxane to this solution, stir and cool, and the internal temperature is 20 ml.
Granular 85% potassium polyhydroxide and SB to keep below ℃
2 mA' of H was added. After that, it was heated at 80℃1 for about 3 hours.
The temperature was raised at 100° C., and the reaction was continued at that temperature for 40 hours. The treatment after the completion of the reaction was the same as in Example 1.

Crude product yield 1 1. 9! ! Yield: 86.2% Insoluble matter: 1.9g Product yield: 9.8g Yield: 71.0Multiple Example 3 Chlorination temperature is 50°C or less, Hofmann elimination reaction time is 40
The procedure was the same as in Example 1 except for the time, and the following results were obtained.

Crude product yield 11.6J9 Yield 84.1 Multi-insoluble matter 0.9# Product yield 10.3g Yield 74.6 Effects of the invention According to the present invention, the chlorination process is significantly simplified and economical. Dichloromethane (2.
2) One paracyclophane can be obtained.

Procedural amendment (voluntary) 1. Indication of the case 1999 Patent Application No. 3 4 2 2 30 2. Name of the invention Method for producing dichloro-(2tz)-ie laciclophane 3. Relationship with the case of the person making the amendment

Claims (2)

[Claims] (1) In the method for producing dichloro-(2,2)-paracyclophane having the following structural formula ▲ Numerical formula, chemical formula, table, etc. ▼ 2 and/or 5 (Image 2
Dichloro-(2,2)- characterized by synthesizing -chloro-p-methylbenzyltrimethylammonium chloride (represented by (5)) and then producing it via quaternary ammonium hydroxide and Hofmann elimination reaction. Method for producing paracyclophane. (2) The manufacturing method according to claim 1, wherein the chlorinating agent is chlorine gas.