JPH0130816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing hydroxydiphenyl ethers.

Hydroxydiphenyl ethers are useful compounds as raw materials for synthetic polymers and organic drugs, but there has been no satisfactory production method to date. A specific reaction example of a method for producing hydroxydiphenyl ethers known so far is that p-methoxyphenol sodium salt and p-methoxybromobenzene are reacted in the presence of a copper catalyst. A method for producing p,p'-dihydroxydiphenyl ether by preparing dimethoxydiphenyl ether and cleaving the ether from it;
p,p'-dibromodiphenyl ether is treated with an alkaline aqueous solution in the presence of a copper halide catalyst to form p,p'-dibromodiphenyl ether.
A method for producing p'-hydroxydiphenyl ether (USP 3290386), a method for directly synthesizing p,p'-dihydroxydiphenyl ether by heating hydroquinone with hydrogen fluoride (USP 2739171),
A method for directly synthesizing p,p'-dihydroxydiphenyl ether from hydroquinone using aluminum silicate as a contact, p-isopropylphenol is dehydrated and condensed under a ThO ₂ catalyst,
p'-diisopropyl diphenyl ether (DE 1810179), oxidize it to dihydroperoxide, and then acid decompose it to p,p'-hydroxydiphenyl ether (USP 4326088)
etc. are known.

However, methods 1 and 2 have the disadvantages that raw materials are difficult to obtain and the yield of the target product is low. In addition, the second method has a low yield and requires the use of toxic hydrogen fluoride, and the second method also has problems in terms of yield. Although the other method has a high yield, it requires a long process, produces unnecessary acetone as a by-product, and has problems in wastewater treatment.

On the other hand, a method for producing p,p'-dihydroxydiphenyl ether from hydroquinone using a strongly acidic ion exchange resin as a catalyst (USP 4316094);
A method for producing p,p'-dihydroxydiphenyl ether from hydroquinone using H-montmorillonite as a catalyst (USP 3886218) is known as a simple method with good yield, but the yield is still not sufficient.

As a result of intensive research into a method for producing hydroxydiphenyl ethers that does not have the above-mentioned drawbacks, the present inventors found that montmorillonite, in which a specific amount of ion-exchangeable ions is composed of metal ions other than H ⁺ ions, has been developed. The inventors discovered that by using a catalyst, hydroxydiphenyl ethers can be produced in high yields with simple operations and suppressed side reactions, leading to the completion of the present invention.

That is, the present invention involves reacting hydroquinones or reacting hydroquinones with monovalent phenols in the presence of a montmorillonite catalyst in which at least 10 mol% of the ion exchange capacity is composed of metal ions other than alkali metal ions. This is a method for producing hydroxydiphenyl ethers.

The montmorillonite catalyst used in the present invention is
Ion-exchangeable ions, i.e. at least 10 mol% of the ion-exchange capacity, preferably 30 to
100 mol% is composed of metal ions other than alkali metal ions.

The montmorillonite catalyst used in the present invention is
Montmorillonite or montmorillonite-based clay minerals, such as bentonite or acid clay, with ion-exchangeable ions, i.e. at least 10 mol% of the ion-exchange capacity, preferably 30
100 mol% is composed of metals other than alkali metal ions. If all of the ion-exchangeable ions are alkali metal ions, at least 10 mol% of them must be exchanged with metal ions other than alkali metal ions, and 10 mol% of the ion-exchangeable ions are already with metal ions other than alkali metal ions. If it is configured, you can use it as is. If 10 mol% or more of the ion exchange capacity is not composed of metal ions other than alkali metal ions, the activity of the catalyst will be low and a huge amount of catalyst will be required for the reactants, which is not practical. Required.

Montmorillonite is a mineral that constitutes clay, and is a phyllosilicate mineral with a layered structure.
Its composition is the general formula M _1/3 (X, Y) _2~3 (Si, Al) ₄ O ₁₀ (OH) ₂・mH ₂ O (where M is an alkali metal such as K or Na, or further Ca, etc.). alkaline earth metal, X is Al,
Fe, Mn or Cr, Y is Mg, Fe, Mn, Ni,
Zn is Li, m is a positive integer),
It is the main component of bentonite and acid clay.

In addition to montmorillonite, clay minerals containing montmorillonite, such as bentonite and acid clay, are also used as raw materials for the catalyst in the present invention.
These commercially available products include "Osmos N" (manufactured by Shiraishi Kogyo Co., Ltd.) and "Benger" (manufactured by Toyojun Yoko Co., Ltd.).

The ion-exchangeable ions in montmorillonite, bentonite, etc. are mainly alkali metal ions represented by M in the above general formula, and the catalyst used in the present invention generally converts at least 10 mol% of these ion-exchangeable ions into alkali metal ions. Prepared by ion exchange with metal ions other than metals.

A known ion exchange method can be used to ion exchange montmorillonite, bentonite, etc. For example, to ion-exchange montmorillonite with aluminum ions, add an aqueous solution of aluminum sulfate, aluminum nitrate, or aluminum chloride to a suspension of montmorillonite so that the amount of aluminum ions added is relative to the amount of ions to be ion-exchanged. Add about 0.5 to 5 times the gram ion equivalent, preferably about 0.8 to 2 times the gram ion equivalent, and stir at room temperature for about 2 to 60 minutes, or leave to stand for ion exchange treatment to solidify. An example is a method in which the phases are separated by filtration or a centrifuge, then washed with water and/or ethanol, and then dried under reduced pressure to normal pressure at a temperature of room temperature to about 100°C. This ion exchange treatment may be repeated multiple times as necessary.

Metals other than alkali metals that are suitable for ion exchange include aluminum, titanium, chromium, zirconium, gallium, cobalt, iron, and nickel.
Zirconium is preferably used.

Metal ion-exchanged montmorillonite is in powder form, and in the present invention, it may be used as a catalyst as it is, or it may be shaped into tablets, spheres, or
It can also be formed into a cylindrical tablet, ring, or honeycomb shape.

Catalysts made of these metal ion-exchanged montmorillonite catalysts have good metal dispersibility and high activity per unit metal. Further, catalysts made of these metal ion-exchanged montmorillonites can be prepared by simple operations.

The amount of the catalyst used in the present invention is arbitrarily adjusted depending on the raw material compounds and reaction conditions, and is generally 5 to 40% by weight based on the hydroquinones or monohydric phenols, but is usually 5% to 40% by weight. It is sufficient to use ~20%.

The hydroquinones used in this reaction are preferably those represented by the following formula [A].

(In the formula, U represents an alkyl group or halogen, and n represents an integer from 0 to 4.) Specifically, hydroquinone, methylhydroquinone, 2,5-dimethylhydroquinone, 2,6-dimethylhydroquinone, trimethylhydroquinone, ethyl Examples include hydroquinone, isopropylhydroquinone, n-hexylhydroquinone, chlorohydroquinone, 2,6-dichlorohydroquinone, and bromohydroquinone.

Further, the monovalent phenols that can be used in the present invention are preferably those represented by the following formula [B].

(In the formula, V is an alkyl group, an aralyl group, an aryl group, a lower alkoxyl group, a halogen, a nitro group,
It represents an acyl group, an aroyl group, etc., and q represents an integer of 0 to 5. ) Specifically, phenol, o
-Cresol, m-cresol, p-cresol, 3,4-xylenol, 3,5-xylenol, 2,4-xylenol, 3,4,5-trimethylphenol, 2,3,4-trimethylphenol, p-ethyl Phenol, p-n-propylphenol, p-n-hexylphenol, p-
benzylphenol, m-benzylphenol,
p-phenylphenol, m-phenylphenol, p-(p'-tolyl)phenol, p-chlorophenol, m-chlorophenol, p-bromophenol, m-bromophenol, 2,4-dichlorophenol, p -methoxyphenol, m
-methoxyphenol, m-nitrophenol,
Examples include p-nitrophenol, m-methoxyphenol, p-methoxyphenol, p-acetylphenol, m-acetylphenol, and p-benzoylphenol.

In the reaction of the present invention, (i) hydroquinones can be used alone, and (ii) hydroquinones and monovalent phenols can also be used as a mixture. In the case of (i), the obtained hydroxydiphenyl ethers are p,p'-dihydroxydiphenyl ethers, and in the case of (ii), they are monohydroxydiphenyl ethers. Particularly in the latter case, a surprising feature of the montmorillonite catalyst used in the present invention is that diphenyl ethers, which are homocondensates of monovalent phenols, are virtually not produced. Therefore, it is very advantageous for improving the yield of hydroxydiphenyl ethers. Also, if we explain with [A] and [B] above, [B] for [A]
If a large excess is used, it is possible to suppress the single condensation reaction of [A] and allow [A] and [B] to react with good selectivity.

The invention can be implemented in various ways.
Among these, liquid phase reaction is preferable in terms of efficiency. In that case, no solvent may be used, but it is usually preferable to dilute with a solvent. The solvent used in that case is
For example, alkylbenzenes such as benzene, toluene, xylene, ethylbenzene, mesitylene, chlorobenzene, dichlorobenzene, bromobenzene, biphenyl, and terphenyl, aromatic ethers such as diphenyl ether, benzofuran, and dibenzofuran, and aromatic ketones such as acetophenone and benzophenone. Among these, alkylbenzenes such as toluene, xylene, and mesitylene are particularly preferred.

The amount of solvent used is usually such that the concentration of the raw material compound is from 2 to 80%, preferably from 5 to 20%.

The reaction temperature is generally in the range of about 80 to about 200°C, particularly preferably in the range of about 110 to about 170°C.

The reaction may be carried out by heating a mixture of a montmorillonite catalyst, a solvent, and a reaction raw material at a predetermined temperature. Heating time is usually about 10 minutes to about 6 hours, preferably about
The duration is 30 minutes to about 2 hours. As the reaction method, various methods can be adopted, such as a conventional batch method, a continuous method using a tube type reaction method, and the like.

Furthermore, the reaction can be carried out under reduced pressure, atmospheric pressure, or increased pressure. Furthermore, since the reaction of the present invention is a dehydration reaction, water is generated as the reaction progresses, so if the reaction is carried out while removing the water in the system by a conventional method, the reaction will proceed more easily.

After completion of the reaction, the reaction mixture was subjected to general separation means such as distillation, with or without separating the catalyst, to obtain the target hydroxydiphenyl ethers. In other words, in addition to hydroxydiphenyl ethers, very small amounts of hydroxytriphenyl ether, hydroxytetraphenyl ether, etc. may be produced as by-products in the reaction product, but these can be easily separated by distillation, etc. can.

According to the present invention, it has become possible to easily produce hydroxydiphenyl ethers in good yield from hydroquinones or hydroquinones and monovalent phenols.

According to the present invention, the reaction rate is also fast, and hydroxydiphenyl ethers can be produced in a higher yield in a shorter time than with conventional catalysts.

Examples are shown below. In addition, the ion exchange rate (mol %) of the metal ion exchange catalyst such as montmorillonite in the examples is the ratio of the amount of alkali metal reduced after metal ion exchange to the amount of alkali metal before metal ion exchange, expressed in mol %. The analysis was based on atomic absorption spectrometry.

Example 1 10 g of bentonite manufactured by Toyosun Yoko Co., Ltd. (trade name Bengel) was suspended in 1 water, stirred well for 24 hours, and then 150 ml of a 5%-Al(NO ₃ ) ₃ aqueous solution was added.
Stirring was continued for 20 minutes, and the bentonite ion-exchanged into an aluminum type was recovered by centrifugation, thoroughly washed with water, and dried (40°C, 50 mmHg, 10 hours) before being used for the reaction.

The ion exchange rate of this aluminum ion-exchanged bentonite was 85 mol%.

This mixture of 4.5 g of aluminum-exchanged bentonite, 14.7 g of hydroquinone, and 150 ml of xylene was placed in a reaction vessel equipped with a Dean Stark water collection trap, and the resulting water was removed from the system by azeotropy with xylene while refluxing the xylene for 35 minutes. Heat and stir,
The dehydration dimerization reaction of hydroquinone was carried out.

The reaction results were as follows.

Hydroquinone conversion rate...65.7% 4,4'-dihydroxydiphenyl ether selectivity
...68.2% Example 2 The same procedure as in Example 1 was carried out except that mesitylene was used instead of xylene. The reaction results were as follows.

Hydroquinone conversion rate...61.1% 4,4'-dihydroxydiphenyl ether selectivity
......69.5% Example 3 10 g of montmorillonite manufactured by Shiraishi Kogyo Co., Ltd. (trade name: Osmos N) was suspended in water from step 1 and stirred well for 24 hours, then 150 ml of a 5% Ti(SO ₄ ) ₂ aqueous solution was added and stirred for an additional 20 minutes. This was followed by ion exchange into a titanium mold.
The montmorillonite ion-exchanged to titanium type was recovered by centrifugation, thoroughly washed with water, and dried (40°C, 50mmHg, 10 hours) before being used in the reaction. The ion exchange rate of this titanium ion exchanged montmorillonite was 83 mol%.

3.0g of this titanium ion-exchanged montmorillonite,
A mixture of 11.2 g of hydroquinone and 110 ml of xylene was placed in a reaction vessel equipped with a Dean Stark water collection trap, and heated and stirred under xylene reflux for 55 minutes while the water produced was removed from the system by azeotropy with xylene. The dehydration and dimerization reaction of The reaction results were as follows.

Hydroquinone conversion rate...67.2% 4,4'-dihydroxydiphenyl ether selectivity
...65.8% Comparative example 1 H ⁺ - obtained by proton exchange using the usual method
Montmorillonite 4.5g, Hydroquinone 14.7g,
A mixture of 150 ml of xylene was placed in a reaction vessel equipped with a Dean Stark water trap, and while the generated water was removed from the system by azeotropy with the xylene, the mixture was heated and stirred under xylene reflux for 35 minutes to dehydrate and dimerize hydroquinone. The reaction was carried out.

The reaction results were as follows.

Hydroquinone conversion rate...7.2% 4,4'-dihydroxydiphenyl ether selectivity
...79.8% Comparative Example 2 The reaction was carried out in the same manner as in Comparative Example 1 except that Amberlyst 15 (7.0 g) was used instead of the H ⁺ montmorillonite catalyst. The reaction results were as follows.

Hydroquinone conversion rate...7.6% 4,4'-dihydroxydiphenyl ether selectivity
...86.3% Example 4 Using the same aluminum ion-exchanged bentonite as in Example 1, hydroquinone and p-cresol were reacted. That is, aluminum ion-exchanged bentonite 3.3g hydroquinone 5.3g, p-
Example 1: 41.6 g of cresol and 100 ml of mesitylene
The reaction was carried out in the same manner as above for 1 hour.

The reaction results were as follows.

Hydroquinone conversion rate...51.0% 4-hydroxy-4-methyldiphenyl ether
...65.0% 4,4'-dihydroxydiphenyl ether selectivity
...31.0% Comparative Example 3 The reaction was carried out in the same manner as in Example 4 except that H ⁺ -montmorillonite was used instead of aluminum ion-exchanged bentonite. The results were as follows.

Hydroquinone conversion rate...10.5% 4-hydroxy-4-methyldiphenyl ether
...59.8% 4,4'-dihydroxydiphenyl ether selectivity
...35.2% Comparative Example 4 The reaction was carried out in the same manner as in Example 4 except that Amberlyst 15 was used instead of aluminum ion-exchanged bentonite. The results were as follows.

Hydroquinone conversion rate...12.7% 4-hydroxy-4'-methyldiphenyl ether
...58.4% 4,4'-dihydroxydiphenyl ether selectivity
...36.5% Comparative Example 5 The reaction was carried out in the same manner as in Example 1 except that aluminum ion exchanged bentonite was replaced with aluminum ion exchanged Y-type zeolite. The results were as follows.

Hydroquinone conversion rate...18% 4,4'-dihydroxydiphenyl ether selectivity
...60%

Claims (1)

[Claims] 1 Hydroquinones are reacted or hydroquinones and monovalent phenols are reacted in the presence of a montmorillonite catalyst in which at least 10 mol% of the ion exchange capacity is composed of metal ions other than alkali metal ions. A method for producing hydroxydiphenyl ethers, which comprises reacting them. 2. The method according to claim 1, wherein the metal ion other than the alkali metal ion is an aluminum ion, titanium ion, chromium ion, or zirconium ion.