KR0127251B1 - Process for preparing of 4,4'-bischloro-methylbiphenyl - Google Patents

Abstract

Title compound(I), useful as an important intermediate for high quality fluorescent brightener, was prepared by the reaction of biphenyl with a chloride selected from paraformaldehyde, oxyphosphorus chloride, phosphorus trichloride and thionyl chloride in an organic solvent such as acetic acid, cyclohexane, n-hexane, dichloroethane and ethylacetate and aqueous HCl solution in the presence of anhydrous zinc chloride catalyst.

Description

Method for preparing 4,4'-bischloromethylbiphenyl

The present invention relates to a process for preparing 4,4'-bischloromethylbiphenyl.

More specifically, the present invention provides a high purity and high yield of 4,4'-bischloromethylbiphenyl of the following structural formula (I) to minimize the amount of heavy metal waste generated as a by-product of the manufacturing process, and to simplify the management and operation. It relates to a method that can be produced by.

In general, various methods for preparing 4,4'-bischloromethylbiphenyl of formula (I), which are generally used as important intermediates in the preparation of high-quality fluorescent whitening agents, are known in various literatures. In the case of manufacturing a low yield, it causes a serious environmental pollution problem such as generating a large amount of heavy metal waste, it is not suitable to apply the preparation methods as it is industrially.

For example, the preparation method described in U.S. Patent No. 3,984,399 provides the purpose of Structural Formula (I) by reacting biphenyl and high purity paraformaldehyde with hydrogen chloride gas in a cyclohexane solution in the presence of a high purity anhydrous zinc chloride catalyst. In the case of preparing the compound or preparing the compound of formula (I) by the above method, the yield is low as 63%, and toxic hydrogen chloride gas and paraformaldehyde, which are difficult to handle, must be used. There is a problem of treating methanol.

In addition, the use of high-purity (98%) zinc chloride used as a reaction catalyst by 0.6 weight times the amount of biphenyl generates a large amount of heavy metal waste, and the corrosion resistance of the hydrogen chloride gas, which is a reactant, is high. Many of them were difficult to apply industrially.

On the other hand, US Patent Publication No. 3,007,975, but the biphenyl and high-purity paraformaldehyde reacted with hydrogen chloride gas in a pressure reactor under a high purity anhydrous zinc chloride catalyst to produce the compound of formula (I), but also the preparation method Since the use of high purity anhydrous zinc chloride 1.6 times by weight with respect to biphenyl, it generates a large amount of heavy metal waste, low reaction yield of 60%, and requires a high pressure reactor, not only hassle in the manufacturing process, The burden on manufacturing costs is also high.

Accordingly, the present inventors have studied various problems described above, and as a result, a method of manufacturing the compound of the structural formula (I) of high yield and high purity by a manufacturing process that is more simple to operate, as well as less pollution burden, Discovered and completed the present invention.

That is, the present invention reduces the burden on environmental pollution by minimizing the amount of heavy metal waste which is essentially generated in the manufacturing process, and is produced during the reaction without using hydrogen chloride gas directly as a reactant to participate in the reaction corrosion of the reaction facility In addition, since it no longer generates high toxicity chloromethanol, an adduct of hydrogen chloride gas and formaldehyde, the manufacturing process is safe and simple and easy to apply in the field, while minimizing the manufacturing cost for the target compound (I). Its purpose and significance are to provide a method for preparing 4,4'-bischloromethylbiphenyl in high purity and high yield.

Hereinafter, the present invention will be described in detail.

The present invention is to react the biphenyl of the following formula (II) with a chloride selected from paraformaldehyde and phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride in the presence of a small amount of anhydrous zinc chloride catalyst in an organic solvent and an aqueous hydrochloric acid solution. The present invention relates to a method for producing the target compound of formula (I).

As the organic solvent used in this reaction, acetic acid, cyclohexane, n-hexane, dichloroethane and ethyl acetate are preferable, and cyclohexane is particularly preferable, and 0.3 to 1.0 weight times of biphenyl is used as the starting material of the reaction. Good to do. The hydrochloric acid solution used together with the solvent can be used as a solution of 0 to 35% concentration. In this case, when the concentration of the hydrochloric acid solution used is 0%, the aqueous hydrochloric acid solution is increased by increasing the amount of chloride used as a reactant. The same reaction effect can be obtained. In addition, as for the anhydrous zinc chloride used as a catalyst, it is preferable to use 0.1-0.2 weight times with respect to biphenyl, and it is especially preferable to use 0.16 weight times.

The use of chloride, which can be said to be the most characteristic element in the reaction according to the present invention, is a configuration that replaces the use of toxic hydrogen chloride gas in the conventional method, selected from phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, and thionyl chloride. When one substance is added to the reaction solution, the chloride reacts with water present in the reaction solution to generate hydrogen chloride gas, and the hydrogen chloride gas thus generated directly participates in the reaction. Such chlorides are preferably used in an amount of 0.3 to 1.7 molar times, and particularly preferably 0.8 to 1.1 molar times relative to biphenyl. In addition, when the reaction amount of chloride is added to the reaction vessel at once, the reaction proceeds violently, making the operation difficult and the selectivity of the reaction. As a result, the production rate of the side reaction product increases and the yield of the main product decreases. This problem can be solved by adding chloride in several times during the reaction, and by adjusting the number of additions, the intensity of the reaction and the reaction time can be controlled. Therefore, the reaction time depends on the reaction conditions, in particular the number of times the addition of chloride, but usually proceeds the reaction for 4 to 24 hours while adding chloride three to three times, the reaction temperature is 30 to 70 degreeC is preferable.

As described above, the present invention is different from the conventional method of preparing the target compound of the present invention, and the reaction process is simple and does not directly use the toxic hydrogen chloride gas, which is difficult to operate and toxic. In addition, it is easy to apply on-site and minimized the use of catalysts and organic solvents, thereby minimizing the burden on manufacturing costs and reducing the burden on environmental pollution.

That is, compared with the prior art, the present invention, first, produced a large amount of heavy metal waste by using high purity (98%) anhydrous zinc chloride, which is expensive as a catalyst and strong hygroscopicity, with 0.6 to 1.6 times of biphenyl. By using only 0.1% to 0.2 times, particularly preferably 0.16 times, 90% zinc chloride relative to biphenyl, greatly reduced the amount of heavy metal reaction waste that is the main culprit of environmental pollution. Despite being affected by the present invention, the present invention, unlike the conventional method that had to use high purity (95-98%) of paraformaldehyde, contained 80% paraformaldehyde, which contained more water and methanol as well as a lower price. The reaction proceeds well even when used. Third, in the prior art, cyclohexane is used as a reaction solvent by using 1.3 to 2 times of biphenyl. While reacting with hydrogen chloride gas and paraformaldehyde in the state, in the present invention, 0.3 to 1.0 times, preferably 0.6 times, cyclohexane with respect to biphenyl is used as a solvent together with water, aqueous hydrochloric acid solution, paraformaldehyde, and oxy. By producing a target compound (I) by reacting a chloride such as phosphorus chloride with biphenyl, the reaction operation is simpler and the manufacturing cost is lowered. Fourth, phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, Chloride, such as thionyl chloride, reacts with water in the reaction solution to slowly generate hydrogen chloride gas, making it possible to simplify the reaction process by allowing chloromethylation of biphenyl without directly using corrosive and difficult toxic hydrogen chloride gas. , Phosphoric acid and sulfuric acid, which are the products after the reaction, act as a reaction catalyst by themselves. As mentioned above, the reaction efficiency is easily controlled by adjusting the number of times of adding chloride as described above.Fifth, the water in the reaction solution not only acts as a solvent but also proceeds slowly. To inhibit the production of side reactions.

As enumerated above, the method for producing 4,4'-bischloromethylbiphenyl according to the present invention not only achieved excellent effects in various respects compared to the conventional method, but also yielded 25 By allowing the preparation of the desired compound (I) in a yield of about 84%, which is as high as%, the present invention provides a whole new method which is much improved compared to the conventional method.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on an Example. However, the present invention is not limited thereto.

Example 1

50 g of 90% zinc chloride, 180 g of 80% paraformaldehyde, 180 ml of cyclohexane, and 100 ml of 35% hydrochloric acid solution are mixed in a 200 ml glass reactor and heated to 30 ° C. with stirring. 170 ml of phosphorus oxychloride is added dropwise at 30 to 45 DEG C for 1.5 hours, and then 308 g of biphenyl is added. 100 ml of phosphorus oxychloride was added dropwise at 35 to 45 ° C for 1 hour, and stirred for 13 hours while maintaining the reaction temperature at 36 to 40 ° C. After raising the reaction temperature to 50-55 ° C., the mixture was stirred for 1.5 hours and 100 ml of phosphorus oxychloride was added dropwise at 50-65 ° C. for 1 hour. After stirring for 3 hours at 60 to 65 ° C., the mixture was cooled to 20 ° C., 400 ml of isopropyl alcohol was added, stirred for 30 minutes, and then filtered. The filtrate was released in 1500 ml of water, stirred for 30 minutes at 30 to 40 ° C, and filtered again. Washed with 200 ml of isopropyl alcohol and dried to give 418.9 g of the title compound as a solid (yield: 83.6%, melting point: 132 to 135 ℃, purity: 94.6%).

Example 2

12.5 g of 90% zinc chloride, 37.8 g of 95% paraformaldehyde, 35 ml of cyclohexane, and 25 ml of 35% hydrochloric acid solution are mixed in a glass reaction vessel and stirred while heating to 32 ° C. 42.5 ml of phosphorus oxychloride is added dropwise at 32 to 42 DEG C for 1 hour, then 78 g of biphenyl are added and stirred at 40 to 45 DEG C for 1 hour. 25 ml of phosphorus oxychloride is added dropwise at 40 to 45 ° C. for 40 minutes and then stirred at 50 to 55 ° C. for 1.5 hours. After further stirring at 60 to 65 ° C. for 3 hours, the mixture was cooled to room temperature, 150 ml of isopropyl alcohol was added thereto, stirred at room temperature for 1 hour, and filtered. The filtrate was released in 500 ml of water, stirred for 1 hour at 30 to 40 ° C., filtered and dried again to give 102.3 g of the title compound as a solid (yield: 81.3%, melting point: 132 to 135 ° C., purity: 93.8). %).

Claims (10)

The biphenyl of formula (II) is reacted with a chloride selected from paraformaldehyde and phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, and thionyl chloride in an organic solvent and an aqueous solution of hydrochloric acid in the presence of a zinc chloride catalyst. The method for producing 4,4'-bischloromethylbiphenyl of (I). The method of claim 1, wherein the organic solvent is selected from acetic acid, cyclohexane, n-hexane, dichloroethane and ethyl acetate. The method according to claim 2, wherein the organic solvent is used in an amount of 0.3 to 1 times by weight relative to biphenyl. The method of claim 1, wherein the zinc chloride catalyst is used in an amount of 0.1 to 0.2 weight times based on biphenyl. 5. The process according to claim 4, wherein the zinc chloride catalyst is used at 0.16 weight times based on biphenyl. The method of claim 1, wherein the chloride is used in an amount of 0.3 to 1.7 molar times with respect to biphenyl. The method according to claim 1, wherein the chloride is used in an amount of 0.8 to 1.1 molar times relative to biphenyl. The method of claim 1, wherein the reaction temperature is 30 to 70 ℃. The method of claim 1, wherein the reaction proceeds for 4 to 24 hours. The method according to claim 1, wherein the concentration of the hydrochloric acid aqueous solution is 0 to 35%.