JPS61260035A - Production of p-phenylphenol compound - Google Patents

Abstract

PURPOSE:To obtain the titled compound easily in high selectivity and yield, by the thermal decomposition dehydrogenation reaction of 1,1-bis(4-hydroxy phenyl)cyclohexane compound in the presence of a hydrogen-transfer catalyst using a phenolic compound as a hydrogen acceptor. CONSTITUTION:The objective compound of formula II is produced by reacting the 1,1-bis(4-hydroxyphenyl)cyclohexane compound of formula I (R1 is H, OH or lower alkyl; R2 is H or lower alkyl) at 200-300 deg.C under 1-40kg/cm<2>G pressure using preferably a phenolic compound as a solvent in the presence of a hydrogen-transfer catalyst such as Pd/C, using a phenolic compound especially preferably a phenol or methylphenol as a hydrogen acceptor. EFFECT:A phenolic compound can be used as a hydrogen acceptor as well as the reaction solvent. The purification and separation of the product are not necessary. The H2 generated in the reaction can be utilized to the reduction of the phenolic compound to the corresponding cyclohexanone compound, which is used as a synthetic raw material of the compound of formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION *ho mLl The present invention relates to an improved method for producing p-phenylphenols. More specifically, in the presence of a hydrogen transfer catalyst,
1. Op-phenylphenols are used in varnishes, Adhesives, Prior Art Many methods have been proposed for producing p-phenylphenols.

For example, a typical conventional production method is to sulfonate biphenyl to produce p-phenylbenzenesulfonic acid, melt and decompose it in the presence of a base, and then precipitate it with acid to obtain p-phenylphenols. be.

In recent years, many methods similar to the method of the present invention have been proposed.

That is, a method in which 1,1-bis(4-hydroxyphenyl)cyclohexane is decomposed to produce p-cyclohexenylphenol, and then subjected to a dehydrogenation reaction in the presence of sulfur as a hydrogen acceptor (Japanese Patent Publication No. 3584/1984) (Japanese Patent Publication No. 45-70
46) has also been proposed.

Also, 1. A method for producing p-phenylphenol by decomposing and dehydrogenating l-bis(4-hydroxyphenyl)cyclohexane in the presence of a catalyst is also known (Japanese Patent Publication No. 18758/1983), in which styrene is An improved method of decomposition and dehydrogenation in coexistence has already been proposed (Japanese Unexamined Patent Publication No. 58-62127).

Problems to be Solved by the Invention However, in the above-mentioned conventional methods, the method using piphenyl as a starting material requires a large amount of acid and base, and the alkaline melt decomposition reaction must be carried out under harsh conditions of 300°C or higher. As an industrial manufacturing method, it must be said that this process involves many problems in terms of equipment, wastewater treatment, energy conservation, etc.

Also, p-cyclohexenylphenol or 1.1
- In the method of producing p-phenylphenol from bis(4-hydroxyphenyl)cyclohexane by dehydrogenation reaction, if a dehydrogenation catalyst and hydrogen acceptor are not used, the yield is low and the efficiency of hydrogen generated in the system is low. It has the disadvantage of not being utilized.

In the methods disclosed in Japanese Patent Publication No. 45-7046 and Japanese Unexamined Patent Publication No. 58-62127, which are improvements on these methods, styrenes such as d-methylstyrene are used as hydrogen acceptors.

However, after the reaction is completed, these hydrogen acceptors are converted into compounds that are not originally related to the production of p-phenylphenols, so it is not only necessary to reuse these hydrogen acceptors, but also to purify and separate them after the reaction is completed. , unless the effective use of hydrogen acceptor compounds such as styrenes is necessarily taken into account.
Industrially, it has the disadvantage of being extremely expensive.

Means for Solving the Problem The inventors of the present invention improved the shortcomings of the conventional methods described above and conducted intensive studies on a method for selectively producing p-phenylphenols in high yield. .1-bis(
The present inventors have discovered that the above object can be achieved by coexisting phenols as hydrogen acceptors when decomposing and dehydrogenating 4-hydroxyphenyl)cyclohexanes, thereby achieving the present invention.

That is, the present invention relates to 1,1-bis(4-hydroxy) represented by the general formula CI p-phenylphenol represented by the general formula (wherein Rz and y are the same as above), which is characterized in that phenol is used as a hydrogen acceptor when subjecting phenyl)cyclohexanes to a thermal decomposition dehydrogenation reaction. It is a manufacturing method of
Since the method of the present invention uses phenols as hydrogen acceptors, it has the following advantages. That is, phenols can be used not only as hydrogen acceptors but also as reaction solvents, and there is no need for purification and separation as in the case where known toluene or the like is used as a reaction solvent. In addition, the hydrogen generated during the production of p-phenylphenols is used to reduce the phenols to the corresponding cyclohexanones, which not only makes effective use of hydrogen, but also converts the generated cyclohexanones into starting materials. 1,1-bis(4-
This is an extremely simple and excellent method for producing p-phenylphenols, as it can also be used as a raw material for synthesizing p-phenylphenols (hydroxyphenyl)cyclohexanes.

The 1,1-bis(4-hydroxyphenyl)cyclohexane that can be used in the method of the present invention has the general formula (I
), and when R1 and R2 are lower alkyl groups, alkyl groups having 1 to 4 carbon atoms can be used, specifically methyl group, ethyl group, n-propyl group, isopropyl group. group, n-butyl group, 5ec-butyl group, tert-butyl group, and isobutyl group. Particularly preferred are 1,1-bis(4-hydroxyphenyl)cyclohexanones in which s R1 and R2 are hydrogen atoms or methyl groups.

Phenols used in the method of the present invention include phenol, methylphenol, ethylphenol,
Examples include isopropylphenol and butylphenol, with phenol and methylphenol being particularly preferred. The amount added to the reaction system is 1,1-bis(4
-Hydroxyphenyl) cyclohexane may be used in an amount of usually 0.1 to 20 mol per 1 mol of cyclohexane, but since the phenol and solvent can be used even if the amount is 6 mol, the selectivity of p-phenylphenols is improved, and preferably 1. Of course, it is also possible to use ordinary organic solvents that are inert to the reaction, such as aromatic hydrocarbons such as benzene, toluene, and cumene, but in that case, the reaction ends. Since it is necessary to carry out post-purification and separation, which is complicated and uneconomical, it is preferable to use phenols as the self-solvent.

The catalyst used in the method of the present invention must have the functions of both a dehydration reaction and a reduction reaction, and normally suitable hydrogenation-reduction reaction catalysts are also suitable for the dehydrogenation reaction. Specifically, Raney nickel, reduced nickel or nickel carrier catalyst, Raney cobalt, reduced cobalt or cobalt carrier catalyst, Raney copper, reduced copper or copper carrier catalyst, noble metal catalyst of Group 8 of the periodic table or the noble metal as a carrier, Examples include catalysts supported on carbon, alumina, barium carbonate, etc., rhenium catalysts such as rhenium-carbon, and copper-chromium oxide catalysts. Among these catalysts, palladium is preferred, and palladium catalysts supported on carriers such as palladium-carbon, palladium-alumina, and palladium-magnesium oxide are particularly preferred. The amount used is usually 0.001A-1.0% by weight, preferably 0.005 to 1.0% by weight of the catalyst metal, based on 1.1-bis(4-hydroxyphenyl)cyclohexane.
0.5% by weight is good.

The reaction temperature is in the range of 200 to 300°C.

If the temperature is lower than this, the reaction rate will be .1% higher, and if it is higher than this, side reactions will occur, which is not a good idea, so a temperature range of 230 to 280°C is preferably selected.

The reaction pressure is usually 1-409/cdG, preferably 2-40/cdG.
A range of 20 kg/cdG is good.

The p-phenylphenols produced in the method of the present invention are obtained by distilling and crystallizing the mixture after the reaction is completed.

It can be obtained by processing according to conventional methods such as extraction.

Next, the method of the present invention will be specifically explained using examples.

Example: In a stainless steel autoclave with an internal volume of 300 d, l#
1-bis(4-hydroxyphenyl) cyclohegisan *yu! 80.411 (0.3 mol), phenol 84.61! (0.9 mol) and 5 pd/carbon 1.6
1p was charged, and the inside of the autoclave was replaced with nitrogen.

The temperature was raised to 250°C, and the reaction was continued at the same temperature for 2 hours.

After hot filtration of the reaction-completed solution to separate the catalyst, the solution obtained by washing the catalyst with phenol was distilled to obtain 51.1 lI of p-phenylphenol. As determined by gas chromatography, the purity was 99.5% (yield 99.5%).

At that time, as a result of quantitative determination by gas chromatography, cyclohexanone was found to be 26.4 II in the recovered phenol.
(0.27 mol) contained Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] (1) In the presence of a hydrogen transfer catalyst, there is a general formula [ I ] ▲ Numerical formula, chemical formula, table, etc. 1,1-bis(4-hydroxyphenyl)cyclohexanes represented by 1,1-bis(4-hydroxyphenyl)cyclohexanes (or a lower alkyl group) are subjected to a thermal decomposition dehydrogenation reaction by adding phenols as hydrogen acceptors. A method for producing p-phenylphenols represented by the general formula [II] ▲Mathematical formulas, chemical formulas, tables, etc.▼[II] (In the formula, R_1 and R_2 are the same as above.)