WO1998011039A1 - Process for the chloromethylation or aromatic hydrocarbons - Google Patents

Abstract

A process for the chloromethylation of aromatic hydrocarbons with a phase transfer catalyst by blowing hydrogen chloride in the presence of formaldehyde, water, sulfuric acid and an inert organic solvent, which is particularly suitable for the preparation of 4,4-bis(chloromethyl)biphenyl from biphenyl through chloromethylation. The process enables the chloromethylation of aromatic hydrocarbons such as biphenyl by simple and easy means in a high yield, particularly the preparation of 4,4-bis(chloromethyl)biphenyl useful as the intermediate for various syntheses in a high yield.

Description

 Specification

 Method for converting aromatic hydrocarbons into methyl

 Technical field

 The present invention relates to a method for chlorinating aromatic hydrocarbons such as alkylbenzene, biphenyl and the like. In particular, the present invention is in demand as a synthetic intermediate for liquid crystal and functional resins. It relates to a method suitable for industrially producing an increasing number of 4,4'-bis (chloromethyl) biphenyls.

 Background technology

 The mono-to-mouth methylation reaction of aromatic derivatives has been studied for a long time. For example, Imoto ♦ Kakiuchi and Huang editor “Holm Aldehyde” Asakura Shoten (Showa 40) has Benzen, Paraholmanore Dehide and Shioh Hydrogen Power, etc. It is strongly shown that benzyl chloride can be obtained. Then, thionyl chloride can be used instead of hydrogen chloride as a chlorine source, and hydrochloric acid can be generated by suspending dry salt powder and decomposing it with sulfuric acid. Is described. As a catalyst, metal chloride is effective, and zinc chloride and tin chloride are particularly mentioned as representatives.

 In addition, Japanese Patent Publication No. 40-3774 discloses that a combination of glacial acetic acid, dried paraformaldehyde (water content of 5% or less), zinc chloride and hydrogen chloride gas is used. A method for producing 4,4'-bis (chloromethyl) biphenyl is disclosed, but bis (chloromethyl) ether is produced due to non-aqueous reaction. It is easy and generates a lot of zinc waste.

Further, Japanese Patent Application Laid-Open No. HEI 3-18809 discloses an inert solution. A method for producing 4,4'-bis (chloromethinole) biphenyl based on a combination of zinc chloride, thionyl chloride and paraformaldehyde in a medium is disclosed. . Although this method has been improved in that hydrogen chloride gas is not used, there is no difference in the reaction yield from the hydrogen chloride gas method, and a large amount of zinc waste is generated. It is not preferred.

 A method using hydrogen chloride gas generated in a reactor is also known, but the efficiency of hydrogen chloride gas generation is low and it is difficult to control the generation rate of hydrogen chloride gas. Yes. Increasing the sulfuric acid concentration and reaction temperature in order to increase the gas generation efficiency increases the proportion of resinous by-products caused by the multiplication of bifu X-nil, and increases the amount of bis (chloromethyl). The yield of biphenyl decreases.

 Regarding the reaction using a phase transfer catalyst, Maurizi 0 Selva, Francesco Trotta and Pietro Tunde have reported (SYNTHES IS No. 11, pl 003 (1991), but this report is also available. In this method, sulfuric acid and food salt are added to the reaction system.

 Accordingly, an object of the present invention is to provide a safe and highly efficient method for the co-methylation of aromatic hydrocarbons in an aqueous system capable of suppressing the production of bis (chloromethyl) ether. In particular, it is intended to provide a method for producing 4,4'-bis (chloromethyl) phenyl.

The present inventors diligently studied the conditions under which the reaction was carried out smoothly in an aqueous system. As a result, a two-liquid phase of an inert organic solvent and water was used, and a mixed catalyst of a phase transfer catalyst and sulfuric acid was used. They found out what to do and led to the present invention. Disclosure of the invention

 In other words, the present invention provides a method for injecting hydrogen chloride gas using a phase transfer catalyst in the presence of formaldehyde, water, sulfuric acid, and an inert organic solvent. This is a method for chloromethylating aromatic hydrocarbons.

 Further, the present invention provides the method for chloromethylating an aromatic hydrocarbon, wherein the phase transfer catalyst is an aromatic quaternary ammonium salt containing nitrogen as a ring constituent atom. In other words, the method is such that the inert organic solvent is an Al channel or a cyclo-Alen channel.

 Further, the present invention provides a bifurcation by blowing hydrogen chloride gas using a phase transfer catalyst in the presence of formaldehyde, water, sulfuric acid and an inert organic solvent. This is a method for producing 4,4'-vis (chloromethylenol) phenyl, which converts phenyl to chloromethyl.

 In the present invention, the aromatic hydrocarbon as a raw material to be chloromethylated is not particularly limited, but may be a monocyclic hydrocarbon such as alkylbenzene. Aromatic hydrocarbons, condensed polycyclic aromatic hydrocarbons such as naphthalene, anthracene, phorolelene, diphenylene oxide, and biphenyl And non-condensed polycyclic aromatic hydrocarbons such as terphenyl, biphenyl and the like. The method of the present invention is particularly suitable for biscuit rometylation of bifunnyl.

The inert organic solvent used in the present invention is of a type as long as the aromatic hydrocarbon as the raw material is soluble and inert to the reaction and incompatible with water. Without limitation, for example, alkanes such as π-heptane and industrial gasoline, and cyclones Cycloalkanes such as hexane are listed. It is preferred that they have a higher boiling point than the reaction temperature. The amount of the inert organic solvent used depends on the solubility of the aromatic hydrocarbon, but is usually 0.5 to 15 by weight, preferably 1 to 8 relative to the raw material aromatic hydrocarbon. It is.

 The amount of water used in the chloromethylation reaction is preferably such that the sulfuric acid concentration when mixed with sulfuric acid is 60 to 85% by weight. If the sulfuric acid concentration is lower than 60%, the reaction becomes extremely slow.If the sulfuric acid concentration exceeds 80%, the aromatic hydrocarbon condensate and other resinous by-products cross-linked with methylene are obtained. Increases and the yield decreases. The amount of sulfuric acid used is 0.2-10, preferably 1-4, in terms of molar ratio to the aromatic hydrocarbon as the raw material. If the amount of sulfuric acid used is less than 0.2, the reaction will be extremely slow or the chloromethyliyi reaction will hardly proceed. On the other hand, if the amount of sulfuric acid used exceeds 10, the aromatic hydrocarbon condensate is easily formed, and the amount of waste acid increases, which is not economical. If the purpose is monochloromethylation, set the sulfuric acid concentration to a lower value within the above range, and aim at biscuit mouth methylation. In such a case, the reaction can be controlled by setting the sulfuric acid concentration to a higher value within the above range.

As the phase transfer catalyst, a known ammonium salt or phosphine salt can be used, and preferably, an ammonium salt is used. And more preferably an aromatic quaternary ammonium salt containing nitrogen as a ring-constituting atom, more preferably a quaternary ammonium halide. It is a combination of salt . Heterocyclic compounds constituting an aromatic quaternary ammonium salt containing nitrogen as a ring-constituting atom include pyridin, quinoline, and isoquinoline. And those having substituents such as methylol and ethyl, for example, picolin and the like. As the halogenated alkyl, a carbon chain length of 8 to 18 is preferable, and a halogen species is preferably chlorine or bromine. Further, these mixtures may be used as a phase transfer catalyst. The amount of the phase transfer catalyst to be used is usually from 0.05 to 0.5, preferably from 0.01 to 0.35, in terms of mole ratio to the starting aromatic hydrocarbon.

 The formaldehyde may be a formaldehyde, a form of formaldehyde generated in the reaction system, or a formaldehyde. Lin, Ha. La Honoré Mole Dehide, Trioxan, Dimethinole Honorema, and the like can be mentioned, and particularly Rho Honore Ménore Dehide is preferred. The amount of Honorem aldehyde used is usually 1.5 to 10 times, preferably 2.0 to 2,000 times as much as that of Binor aldehyde. It is eight. In addition, the stoichiometric ratio according to the number of chloromethyl groups to be introduced is generally 0.5 to 5, preferably 1.0 to 3.

In addition, the supply amount of hydrogen chloride gas should be at least 1 times, preferably 1.5 to 5 times, the molar ratio of the aromatic hydrocarbon used as the raw material. If the ratio is less than 1, the amount of resinous by-products increases, and the yield of chloromethyl compounds such as 4,4'-bis (chloromethylen) biphenyl is reduced. If it decreases and exceeds 5 times, only hydrogen chloride released to the outside of the reaction system will increase, which is economical. Is not preferred. In addition, the stoichiometric ratio according to the number of chloromethyl groups to be introduced is usually 0.5 to 5, preferably 1.0 to 3.

 The reaction temperature is from 40 to 120 ° C, preferably from 60 to 90 ° C, and the reaction time is usually from 1 to 10 hours, depending on the conversion of the aromatic hydrocarbon. It is determined from The reaction pressure may be normal pressure or pressurization. However, if the reaction is performed under pressurization, tris (chloromethyl) biphenyl is required. There is a tendency for the amount of polysubstituted (chloromethyl) aromatic hydrocarbons to increase, and normal pressure is simpler and more preferable. In addition, the ratio of the aqueous solution phase to the organic solvent phase in the liquid phase should be between 1: 9 and 9: 1. When a bischloromethyl compound such as 4,4, -bis (chloromethyl) biphenyl is intended, the temperature should be relatively high within the above range. By setting, the selectivity can be controlled.

 In the reaction of the present invention, not only the liquid phase becomes two phases but also a heterogeneous system consisting of a solid phase, a liquid phase, and a gaseous phase in many cases. Therefore, stirring is performed during the reaction. Is necessary. Although the reaction method is not particularly limited, a method in which water required for dilution is charged into the reaction system, and concentrated sulfuric acid is added dropwise later, the dehydration reaction causes A large amount of condensates of aromatic hydrocarbons cross-linked are formed.

After the completion of the reaction, the reaction solution is cooled, neutralized, and filtered to collect a crude product. The crude product is washed, for example, with water, and dried to obtain a 4,4'-vis (chloro). (Methylenol) It is possible to obtain a chloromethyl compound of an aromatic hydrocarbon such as bivinyl. What In order to obtain a further purified crystal, for example, when the purpose is 4,4, -bis (chloromethyl) biphenyl, it is obtained by filtration. After washing the resulting cake with water to remove sulfuric acid, hydrochloric acid, inorganic salts, etc., the solvent-soluble components such as heated n-heptane and industrial gasoline are extracted, and the solution For example, in the case of 4,4, -bis (chloromethinole) biphenyl, crystals having a purity of about 99% can be obtained.

 When the reaction solution is stirred according to the method of the present invention, the organic solvent is dispersed in small droplets, and the biphenyl is dissolved and dispersed in these droplets. Since the reaction substrate dissolved in the organic phase and the hydrogen chloride dissolved in the aqueous phase are distributed in different phases, it is thought that the phase transfer catalyst moves in both phases and reacts efficiently. .

 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In Examples, acetyl pyridinium chloride is abbreviated as CPC.

 Example 1

35 g (23 Ommol) of biphenyl, 7.8 g (2.3 mmol) of CPCO, no. A mixture of 15 g (460 mmol) of rahonolemethanol, 90 g of π-heptane, and sulfuric acid of the concentration and amount shown in Table 1 was equipped with a stirrer and a capacitor. 50 O ml Charge into a round-bottomed flask, and inject hydrogen chloride gas (4 times the amount to biphenyl) at 80 ° C continuously for 5 hours. I responded. The reaction results are shown in Table 1. In Table 1, B p represents bifenolino, and BCMBp represents 4,4, -bis (cloth methyl) biphenyl. 【table 1 】

 Example 2

 177 g (500 mmol) of biphenyls, 1.8 g (5 mmo1) of CPC, no, 33 g (1.1 mo1) of dehydrocarbons, Charge 200 g of n-heptane and 250 g of 80% sulfuric acid to a 1 liter round bottom flask equipped with a stirrer and a condenser, and add The mixture was stirred at a temperature of ° C while continuously injecting hydrogen chloride gas (injection amount = 2 mol) and reacted for 7 hours. When the reaction product was analyzed by gas chromatography, the biphenyl conversion was 100% and the 4,4'-vis (chloromethyl) bi The yield of platinum was 59.6%.

 Example 3

Biphenyl 35 g (230 mmol). CPC 1.75 g (5 mmol), parahonolamide aldehyde 15 g (460 mmol), n-heptane 90 g of tan and 100 g of 80% sulfuric acid are placed in a 500 ml round bottom flask equipped with a stirrer and a capacitor, and gaseous hydrogen chloride is added at 80 ° C. The reaction was continued for 5 hours while continuously injecting (4.4 times the molar amount to bivinyl). The conversion of biphenyl was 100%, and the yield of 4,4'-bis (chloromethine) biphenyl was 54%. Example 4

 A chloromethylation reaction was performed in exactly the same manner as in Example 3, the reaction product was cooled to room temperature, and then neutralized with an aqueous caustic soda solution. After removing the aqueous layer separated in the lower layer, add 100 g of methanol and 20 g of granular soda to the upper organic layer containing solids, and heat to reflux for 2 hours. The reaction was continued. The reaction product was processed according to a conventional method to obtain a brown liquid. When this liquid was analyzed by gas chromatography, it was found that it contained 2,6.9 g of 4,4'-bis (methoxymethyltinole) biphenyl. Was. The yield of Bifu-Ninoru-Ken, et al. Was 47.1%.

 Example 5

 90.5 g of biphenyls, 1.1 g of CPC 21, 92%. 38.2 .2 g of Lahonolem aldehyde and 1801 g of industrial gasoline No. 5 were charged into a 10 £ flask equipped with a stirrer and a capacitor. While blowing in hydrogen chloride gas, 240 g of 80% sulfuric acid was added dropwise at 80 ° C. over 4 hours, and the reaction was further continued for 1 hour with stirring. The amount of hydrogen chloride gas injected was 9500 g, which was 4.5 times the molar amount of bivinyl.

 After completion of the reaction, the reaction solution was cooled and neutralized with an aqueous ammonia solution. The neutralized reaction product was filtered to obtain 186 g of a water-containing solid. As a result of gas chromatographic analysis of this solid by the internal standard method, the transfer ratio of biphenyl was 100% and 4,4'-bis (chloromethylen) was obtained. The yield of bipheninole was 54.8%.

 Example 6

90.7 g of Bifu Ninore, 21.3 g of CPC, 92% 38.2 .2 g of parahonolemaldehyde, and the mono (chloromethinole) bivinyl and bis (chlorome) recovered after filtration in Example 5 Chill) 150 g of industrial gasoline layer containing biphenyl, etc. and 506 g of fresh industrial gasoline No. 5 were mixed with a stirrer and a condenser. The mixture was charged into a 10% glass flask equipped with a sensor, and while blowing hydrogen chloride gas at 70 ° C, 230% sulfuric acid (2,370 g) was added. (3.3 times mol) was added dropwise over 4 hours, and then the mixture was further reacted for 5 hours while stirring. The amount of hydrogen chloride gas injected was 580 g (2.7 times the mol of biphenyl).

 After the completion of the reaction, the reaction mixture was treated in the same manner as in Example 5 to obtain 2041 g of a water-containing solid. The conversion of biphenyl was 100%, and the yield of 4,4'-bis (chloromethylen) biphenyl relative to the charged biphenyl was 5%. It was 7.6%.

 Example 7

 90 g of biphenyl was charged with CPC, 92% paraffin phenol, and industrial gasoline No. 5 at the same rate as in Example 5 above, and hydrogen chloride gas was added. 60% sulfuric acid was added dropwise while blowing air, and the mixture was reacted at 90 ° C for 5 hours. After neutralizing the reactants in the same manner as in Example 5, the average sample was analyzed. As a result, the conversion of biphenyl was 69% and that of 4-chloromethyl biphenyl was as follows. The yield of metal was 39.7%.

 Example 8

The raw materials were charged in the same manner as in Example 5, the reaction temperature was set to 70, the amount of hydrogen chloride gas blown was 3.2 mol times the amount of bivinyl, and the reaction was carried out for 9 hours. . Subsequent processing is the same as in Example 5. As a result of analyzing the obtained solid matter, the conversion of bif X-nil was 100% and that of 4,4'-bis (chloromethylen) biphenyl The yield was 62.3%.

 Example 9

 17 g of biphenyl phenol, 3.4 g of CPC, 6.6 g of 92% phenol, and 35 g of industrial gasoline No. 5 The flask was charged into a 20 O ml flask, and while blowing in hydrogen chloride gas, 40 g of 80% sulfuric acid was added dropwise at 50 ° C. with stirring, and the mixture was reacted for 3 hours.

 The reaction was treated as in Example 5, and the resulting solid was analyzed. The conversion rate of biphenyl is 98.6%, and the prepared biphenyl is 4,4'-bis (chloromethinole) bif. The yield of ル -liter was 46.5%.

 Comparative Example 1

 In the same manner as in Example 3, except that the CPC was omitted, the same procedure was carried out except that the CPC was omitted. As a result, the transfer ratio of the biphenyl was 32.5%, The yield of 4,4, -bis (chloromethinole) biphenyl was 13.0%.

 Industrial applicability

 ADVANTAGE OF THE INVENTION According to this invention, the chloromethyl Luich of aromatic hydrocarbons, such as biphenyl, can be performed easily and with good yield. Further, according to the present invention, 4,4, -bis (chloromethyl) biphenyl useful as a synthetic intermediate for various purposes is produced with good yield. can do .

Claims

The scope of the claims  (1) Aromatic carbonization by injecting hydrogen chloride gas using a phase transfer catalyst in the presence of formaldehyde, water, sulfuric acid, and an inert organic solvent A method for the chloromethylation of aromatic hydrocarbons, characterized in that hydrogen is chloromethylated.  (2) The phase transfer catalyst is an aromatic quaternary ammonium salt containing nitrogen as a ring-constituting atom, and the inert organic solvent is aluminum or cycloalkane. A method for the co-methylation of an aromatic hydrocarbon according to claim 1.  (3) Biphenyl is blown by blowing hydrogen chloride gas using a phase transfer catalyst in the presence of formaldehyde, water, sulfuric acid, and an inert organic solvent. A method for producing 4,4'-vis (chloromethine) biphenyl, which is characterized in that it is made from chloromethyl.