JPS595132A - Preparation of 4-chloro-3,5-xylenol - Google Patents

Abstract

PURPOSE:To prepare the titled compound useful as a disinfectant, etc., with a simple apparatus at low raw material cost, in high selectivity and purity, by chlorinating 3,5-xylenol with hydrochloric acid in a solvent using a copper salt as a catalyst adding the aqueous solution of H2O2 dropwise to the system. CONSTITUTION:The objective compound can be prepared in a selectivity of as high as 80 odd % and a purity of >=99% by the liquid phase oxychlorination of 3,5-xylenol with HCl-H2O2 at 15-35 deg.C, by adding a 35-60% aqueous solution of H2O2 dropwise to a mixture of (A) 3,5-xylenol, (B) an organic solvent, preferably a halogenated lower aliphatic hydrocarbon such as difluoroethane, (C) 20-35% hydrochloric acid, and (D) a copper salt catalyst. The copper salt is e.g. CuCl2, CuCl, CuI, Cu (CH3COO)2.2H2O, etc., especially CuCl2 or CuCl, and its amount is preferably 1-10wt% based on 3,5-xylenol. The amount of the aqueous solution of H2O2 is preferably 1.0-1.2 moles per 1 mole of the chlorine required to attain the objective degree of chlorination.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 4-chloro-3,5-xylenol.

4-Chloro-5,5-xylenol is an industrially important compound as a tungstenicide, a fi agent, and an intermediate thereof.

It is produced by chlorination of 3,5-xylenol, but the major challenges for industrial production methods are obtaining high selectivity during chlorination and establishing an inexpensive production method.

The object of the present invention is to provide an industrially advantageous manufacturing method for producing a chlorinated product of 5,5-xylenol, which has a high selectivity for the target product, has low raw material costs, and can be produced using simple equipment. .

There have been several reports regarding the chlorination of 5.5-xylenol, for example, Japanese Patent Publication No. 45-408.
According to Publication No. 82, 3.5-xylenol was added to CuCt! in a hot hydrochloric acid solution. The method of chlorinating with C as a chlorinating agent is
According to Japanese Patent Application Laid-Open No. 49-55544, 5.5-
According to Japanese Patent Publication No. 55-5335, xylenol is similarly chlorinated in a hot hydrochloric acid solution using CuCLz as a catalyst by introducing alpha gas, and according to Japanese Patent Publication No. 55-5335,
A method of chlorinating with at least one metal chloride sulfuryl chloride selected from the group consisting of Lz, TiCz4 and 8b(z) and a method using the system JP-A-56-1!11555 A method has been reported in which 4-chloro-3,5-xylenol is obtained with high selectivity by chlorinating TeH(J-HtO*!) using VCI%tct3 or FeCj4 as a catalyst.

However, each method has various points that need to be improved for industrial production. That is, in the technique disclosed in the above-mentioned publication, there are problems with the equipment for using hot hydrochloric acid, a! safety issues when using chlorinating agents; increased economic burden due to the complexity of the process for regenerating chlorinating agents;
There are troubles due to tar formation caused by t2 gas, and the use of Japanese Patent Publication No. 55-5555 requires high raw material costs and absorption and removal of generated SOf, and equipment for that purpose. The main ones are necessary. Furthermore, regarding JP-A No. 56-13153, the present inventors described At(1
When a follow-up experiment was conducted using 3 and Fe (J4 catalyst), the selectivity of 4-chlor form (p-chlor form) h'- was low;
The results of the examples in the publication could not be reproduced. Therefore, as a result of intensive research on catalysts, we found that due to the use of copper salt catalysts, the dichlor formation rate was extremely low, and the 4-chlor formation selectivity was around 80%. We have now discovered a catalyst that exhibits extremely high selectivity.

Furthermore, in the invention, the raw materials used are HCt water*H2O2 water and copper salt, which are all common materials, and are inexpensive and pose no problem in handling. In addition, the reaction proceeds satisfactorily at room temperature.

There is no self-decomposition of n, o, and there is no need for excessive preparation.

Regarding purification and extraction, there are advantages such as the ability to easily obtain a highly purified product with a purity of 99% or more by directly cooling and crystallizing the oil layer of the reaction solution.

Copper salts are used as catalysts used in the present invention, and CuCl and CuCl are particularly preferred, and it is necessary to use them in an amount of 0.01 to 20% (by weight) based on 5.5-xylenol. Preferably it is 1% to 10%.

The concentration of hydrochloric acid used is in the range of 5 to 35%, but it is desirable to use a high concentration of 20 to 55% in view of the liquid volume, and there is no effect on the selectivity due to the concentration. The amount of sulfuric acid may be changed as appropriate depending on the required degree of chlorination, and may be about 1.01 to 2.0 times the mole of the desired degree of chlorination relative to 3.5-xylenol, but if it is too small, the reaction may occur. Since this causes a decrease in speed, the appropriate amount is preferably 1.5 to 2.0 times the mole. Further, the concentration of the aqueous hydrogen peroxide solution used in the present invention is in the range of 5 to 60%, preferably 35 to 60%. The appropriate amount of hydrogen peroxide aqueous solution to be used is 1.0 to 1.2 times the mole of the desired degree of chlorination.
This will result in a decrease in the yield of chloride. It is best to keep the reaction temperature as low as possible, but considering the reaction rate, a temperature of 15 to 55°C is recommended.
Yo? ) the best effects of the invention are achieved.

The chlorination method of the present invention involves dissolving 5,5-xylenol in a halogenated hydrocarbon, an organic acid, a halogen-substituted aromatic hydrocarbon, etc., and reacting in the presence of a solvent. Considering the treatment, I-logenated lower aliphatic hydrocarbons such as dichloroethane, cHct, , CCl4, etc. are preferred.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 50 parts of dichloroethane was added to a four-piece parallel flask equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser.6.
40 parts of 5-xylenol, 73 parts of 35% hydrochloric acid, and 5 parts of CuC1z as a catalyst were charged, and while stirring and maintaining the temperature at 20 to 50°C, 17 parts of a 55% aqueous hydrogen peroxide solution was added from the dropping funnel over 60 minutes, followed by another 5 parts. 2 at °C. Stir for one hour to react. After the completion of the reaction, the mixture was separated for 1 minute, and the dichloroethane layer was washed with water. A portion of the mixture was sampled and analyzed by gas chromatography. As a result, the following composition was obtained.

5.5-xylenol 59.9 mol% p-chloro-5,5-xylenol 54.010-ria
3.5-xylenol 6.0#2.4-dichloro-3,5-xylenol 0. Ol”p+o ratio, 85.0% Note) p is p-chloro-3,5-xylenol, 0
is O-chloro-3,5-xylenol as yb-t-0
Examples 2 to 4 Table IK shows the analytical results obtained when other copper salts were used in place of the catalyst Cu C14 by the same operation as in Example 1.
Indicated.

Table 1VC also shows the results of Comparative Examples 1 to 4 in which no catalyst was used and in which other metal salts were used in place of the copper salt according to the present invention.

Table 1 Kono notation Color light cut yo5 IC, AtCz4,
When FeC4O and 5bczs were used as catalysts, p/p+ was compared to when no catalyst was used. There was not much difference in the ratio.

Example 5 Using the same reaction apparatus as in Example 1, 96 parts of carbon tetrachloride,
5.5-xylenol 40 parts, 35% hydrochloric acid 75 parts and C
5 parts of uCty were charged, and while stirring, 35 parts of 35% hydrogen peroxide was charged from the dropping funnel at 25 to 30°C over 60 minutes, and the mixture was further stirred at VC 50°C for 6 hours to carry out one reaction. p-chloro-3,5-xylenol begins to precipitate during the reaction. After the reaction is completed, the temperature of the reaction solution is raised to 60° C. to completely dissolve the reaction product. After separating and washing with water, a portion of the carbon tetrachloride reaction solution was sampled and analyzed by gas chromatography pressure, and as a result, the following composition was obtained.

3.5-xylenol 2.5 mol% p-chloro-5-xylenol 7c13
0-Chlor # 16.7 Dichlor 11.4 p/p+. The ratio was 82.6%. This reaction solution was gradually cooled, the precipitated crystals were separated in a furnace, and 1
Washing with 24 parts of carbon tetrachloride at 5°C gave 34.7 parts of crystals (
yield of 68%). The crystals were needle-shaped pure white crystals, and the results of gas chromatography analysis were as follows.

5-xylenol a5% by weight p-chloro-5-xylenol 99.5 #Example 6 In the same manner as in Example 5, 215 parts of Cu (215 parts) was used instead of the catalytic CuCtl. The results of sampling and analyzing the area are as follows.

45-xylenol 59 mol%p-chloro-45-xylenol 75.9#0-chloro-#
1a6#dichlor-#
1.6#p/p+. The amount of crystals obtained was 5 parts and 7 parts (yield 66%), and the results of gas chromatography analysis were as follows.

He5-xylenol 0.4% by weight p-
Chlor-45-xylenol 99.6#Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] 6. Drop an aqueous hydrogen peroxide solution into a mixture of 5-xylenol, an organic solvent, a catalyst, and hydrochloric acid, and add HCiL-H10.
A method for producing 4-chloro-3,5-xylenol, characterized in that a copper salt is used as a catalyst in chlorination by two-liquid phase oxychlorination.