JPH08337546A - Separation and purification of m-ethylphenol - Google Patents

Abstract

PURPOSE: To obtain the subject compound having a high purity, by separating from a mixture of ethylphenol isomers by utilizing a simple means of using a specific host compound capable of selectively forming a host guest complex with m-ethylphenol. CONSTITUTION: This method for the separation and purification of m-ethylphenol comprises contacting a mixture of ethylphenol isomers containing m-ethylphenol with a host compound consisting of tetraphenylphosphonium bromide or 1,1-di(4- hydroxyphenyl)-cyclohexane to precipitate a material containing a host guest complex of m-ethylphenol, and then separating a solid from a liquid. Preferably, by adding 0.2-2 fold mol host compound to the above isomer mixture, heating up to 100-150 deg.C to provide a uniform phase and then cooling to (-)5-15 deg.C, the complex crystals are precipitated. Further, in order to obtain the object compound from the above complex, the complex is preferably heated at 150-200 deg.C under a reduced pressure sufficient for vaporizing m-ethylphenol at that temperature to decompose and vaporize the complex.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for separating and purifying m-ethylphenol which is useful as an intermediate for medicines, agricultural chemicals, photographic agents and the like. More specifically, by using a compound (host compound) that selectively forms a host-guest complex with respect to m-ethylphenol (guest compound), m-ethylphenol is removed from an ethylphenol isomer mixture containing m-ethylphenol. The present invention relates to a method of separating and purifying.

[0002]

2. Description of the Related Art There are several known methods for producing m-ethylphenol. An old example is sulfonation of ethylbenzene (for example, Japanese Patent Publication No. 49-33192 and Japanese Patent Publication No. 49-33193). This is a method of hydrolyzing sulfonic acids other than the m-form from the ethylbenzene sulfonic acid mixture and melting the remaining m-form with an alkali. In addition, using a specific aluminosilicate catalyst
A method of selectively decomposing p-ethylphenol in a mixture of -and p-ethylphenol to obtain the remaining m-ethylphenol has also been reported (Japanese Patent Publication No. 2-242).
59).

Further, a method by ethylation of phenol has also been investigated. In this method, a mixture of o-, m-, p-ethylphenol is obtained, and after o-ethylphenol is separated by distillation, m-ethylphenol is separated and recovered by adsorption separation or the like.

[0004]

The above-mentioned sulfonation method of ethylbenzene has a problem that sulfuric acid and sodium hydroxide, which are dangerous to handle, must be handled at a relatively high temperature, and a large amount of harmful waste water is generated. .

The method using an aluminosilicate catalyst is as follows:
Since the reaction is carried out at a temperature as high as 450 ° C., there are problems in yield reduction due to thermal decomposition and operability.

In the method of separating and recovering m-ethylphenol by adsorption separation or the like, the separability of p-ethylphenol is not sufficient, and the higher the separation rate, the lower the yield, and the higher the yield, the lower the purity. There was a problem.

An object of the present invention is to solve the above problems and to provide a method capable of separating and obtaining m-ethylphenol with high purity from an ethylphenol isomer mixture by a simple means.

[0008]

[Means for Solving the Problems] The inventors of the present invention have made earnest studies to develop means capable of solving the above-mentioned problems, and separation using a host-guest complex known as a separation technique for isomers of phenol compounds. Focusing on the method, a broad search was conducted for host compounds that can be selectively included as a guest compound with m-ethylphenol. As a result, they found that a specific compound was effective as this host compound,
Based on this finding, the present invention has been completed.

That is, according to the present invention, an ethylphenol isomer mixture containing m-ethylphenol is contacted with tetraphenylphosphonium bromide or 1,1-di (4-hydroxyphenyl) -cyclohexane to give m-ethylphenol.
The present invention relates to a method for separating m-ethylphenol, which comprises depositing an ethylphenol-containing substance and subjecting it to solid-liquid separation.

The type of ethylphenol isomer mixture to which the present invention can be applied is not particularly limited, but usually about 40 to 95 wt% of m-ethylphenol, preferably 65 to 65% by weight.
95%, p-ethylphenol 5-60%,
It preferably contains about 5 to 30%. Furthermore the third
Ingredients may be included, for example, 0 to 20% of o-ethylphenol, especially 0 to 10%, diethylphenol of 0 to 5%, especially 0 to 3%, and other phenols of 0 to 10%. %, And particularly about 0 to 5%. O-form in a mixture of ethylphenol isomers,
The content of all ethylphenol isomers including the m-form and the p-form is 85 to 100%, usually about 90 to 95%. Such an ethylphenol isomer mixture is usually liquid at normal temperature, and can be produced, for example, by sulfonation of ethylbenzene-melting with alkali, and ethylation of phenol with ethylene or ethanol.

Tetraphenylphosphonium bromide can be easily obtained by reacting triphenylphosphine with phenylmagnesium bromide in ether and is commercially available as an industrial chemical. This product is a white solid at room temperature and has a melting point of 287 ° C.

1,1-di (4-hydroxyphenyl)-
Cyclohexane is industrially produced from cyclohexane and phenol and can be easily obtained, and the details thereof are described, for example, in JP-A-62-263135. It is a white solid crystal at room temperature and has a melting point of 175 ° C. or higher.

As a method for forming a host-guest complex in the present invention, one of the above-mentioned host compounds is added to an ethylphenol isomer mixture to form a homogeneous phase.

The amount of the host compound added is about 0.05 to 5 times mol, preferably about 0.2 to 2 times mol, based on the molar ratio of the ethylphenol isomer mixture. As a means for uniformly dissolving the host compound and m-ethylphenol, which is the guest compound, simple stirring may be sufficient, but heating is preferable for shortening the operation time. The heating temperature is not particularly hindered as long as the guest compound m-ethylphenol does not significantly evaporate and escape, but is usually 40 to 180 ° C, preferably 100 to 150 ° C.
The degree is appropriate. A solvent can be used in the method of the present invention, and when the solvent is a low boiling point solvent, the temperature is naturally lower than the boiling point of the low boiling point solvent. The boiling point at this time varies depending on the pressure of the system, and can be carried out under pressure if necessary.

The temperature at which the complex crystals are deposited may be room temperature, but the temperature may be lowered to room temperature or lower by using a cooling medium, or in the case of crystals that are difficult to deposit, cooling may promote the deposition to shorten the time required for the deposition. It is also possible. In that case, −
It is preferable to lower the temperature to about 15 to + 30 ° C, preferably -5 to + 15 ° C. The time required for precipitation is not particularly limited, but a shorter time is desirable. The time required for precipitation, that is, the time from the addition of the host compound to the solid-liquid separation is usually 1
It is about 0 minutes to 20 hours.

A solvent may be used in the method of the present invention. As the solvent, esters such as methyl acetate and ethyl acetate, ketones such as acetone and butenone, and nonpolar hydrocarbons such as n-pentane and cyclohexane can be used alone or in combination. This solvent is used for adjusting the crystal grains of the host-guest complex and the production rate, and for facilitating the recovery of the complex from the system, and it is not particularly necessary to use it if it can be carried out without a solvent.

Means for solid-liquid separation of the precipitated complex crystals may be filtration or centrifugation. After separation, wash as necessary. The washing may be appropriately selected from the above solvents.

The m-ethylphenol-containing product thus obtained can be recovered as white columnar crystals having a length of about 0.5 to 2.0 mm at room temperature.

As a method for obtaining m-ethylphenol from the m-ethylphenol-containing substance which is a host-guest complex, a method of decomposing and vaporizing m-ethylphenol which is a guest compound by heating is convenient. The condition for heating and recovering this m-ethylphenol is a temperature of about 300 ° C. or lower at which thermal decomposition of the host compound itself does not occur and a temperature at which the guest compound can be vaporized and distilled. Usually 100 to 250 ° C, preferably 150 to 20
0 ° C. is suitable, and the reaction is carried out under reduced pressure conditions at which m-ethylphenol can be vaporized.

[0020]

[Function] Separation using a host-guest complex is a separation method that utilizes the formation of a specific crystal structure by allowing another compound to enter a vacancy of a three-dimensional structure formed by binding a certain compound with a certain composition, Although it is different from distillation, it is a relatively easy physical separation method. A skeleton compound is a host compound,
The compound that has entered the vacancy is called the guest compound, and the crystal of the host compound that has incorporated the guest compound is separated from the system,
The target substance is obtained by re-decomposing.

Two host compounds used in the present invention, tetraphenylphosphonium bromide or 1,1-di
It is not clear how (4-hydroxyphenyl) -cyclohexane acts at the stage of forming the host-guest complex, but both at the stage of mixing the host compound and the guest compound. Form crystals with a mixed stoichiometry. The host compound is arranged and crystallized with a certain number of pores, and a specific compound in which the pores have a matching molecular size, electrical environment, etc., m-ethylphenol is selectively selected in the present invention. It will be crowded. The incorporated host-guest complex becomes crystals and is easily separated from the solution.

The m-ethylphenol present in the separated complex crystals is present via hydrogen bonding in the lattice of tetraphenylphosphonium bromide or 1,1-di (4-hydroxyphenyl) -cyclohexane. Therefore, if this complex was heated, it was easily incorporated.
-Can drive off ethylphenol.

[0023]

EXAMPLES The present invention will now be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 5.0 g of tetraphenylphosphonium bromide (11.
9 mmol) and mixed ethylphenol (m-ethylphenol 67.0%, p-ethylphenol 25.0%,
2,6-diethylphenol 4.8%, other 3.2%
Total 100%) 2.0 g (16.
4 mmol) and 10 ml of acetone are added and dissolved at room temperature. Crystals were precipitated when the solution was left standing for 12 hours at room temperature. Therefore, the crystals were separated by filtration, washed with hexane and then weighed to find that it was 2.7 g. 2 this crystal
When heated under the condition of 00 ° C / 20 mmHg, m
-0.6 g of ethylphenol recovered. The gas chromatographic analysis of this recovered product showed that m-ethylphenol was 92.8% and p-ethylphenol was 6.0%.
showed that.

Example 2 2.0 g (7.5 mmol) of 1,1-di (4-hydroxyphenyl) cyclohexane and mixed ethylphenol (the composition is the same as in Example 1) 1.3 g (ethylphenol conversion 1
0.7 mmol) and 10 ml of ethyl acetate were added, and the temperature was 40 ° C.
Dissolve in. When the solution was allowed to stand at room temperature for 24 hours, crystals were precipitated. Therefore, the crystals were separated by filtration, washed with hexane and then weighed to find 2.6 g. 20 this crystal
When heated at 0 ° C./20 mmHg, 0.55 g of m-ethylphenol was recovered.

A gas chromatographic analysis of this recovered product showed that m-ethylphenol was 96.8% and p-ethylphenol was 2.5%.

Example 3 2.0 g (7.5 mmol) of 1,1-di (4-hydroxyphenyl) -cyclohexane and 5.0 g (41.0 mmol) of mixed ethylphenol (having the same composition as in Example 1) were not used. It dissolves at 40 ° C. in a solvent. Crystals were precipitated soon after the solution was left at room temperature, and the crystals were washed with hexane by filtration and then weighed to find 3.0 g.
When this crystal was heated under the condition of 200 ° C./20 mmHg, 0.85 g of m-ethylphenol was recovered. The gas chromatogram analysis of this recovered product showed m-ethylphenol 98.6% and p-ethylphenol 1.3%.

[0028]

By applying the method of the present invention,
High-purity m-ethylphenol can be easily recovered from an ethylphenol isomer mixture containing m- and p-ethylphenol.

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[Procedure amendment]

[Submission date] July 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The m-ethylphenol-containing material thus obtained can be recovered as white columnar crystals at room temperature.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

As a method for obtaining m-ethylphenol from the m-ethylphenol-containing substance which is a host-guest complex, a method of decomposing and vaporizing m-ethylphenol which is a guest compound by heating is convenient. This m-
The condition for heating and recovering ethylphenol is a temperature at which thermal decomposition of the host compound itself does not occur, which is about 300 ° C. or lower, and a temperature at which the guest compound can be vaporized and distilled. Usually 100 to 250 ° C, preferably 150 to 20
0 ° C. is suitable, and the reaction is carried out under reduced pressure conditions at which m-ethylphenol can be vaporized.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuki Sekiguchi 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Adchemco Co., Ltd.

Claims (1)

[Claims] 1. An ethylphenol isomer mixture containing m-ethylphenol is converted into tetraphenylphosphonium bromide or 1,1-di (4-hydroxyphenyl).
-A method for separating m-ethylphenol, which comprises contacting with cyclohexane to precipitate an m-ethylphenol-containing substance, and subjecting this to solid-liquid separation