JP3269938B2 - Method for separating and purifying m-ethylphenol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating and purifying m-ethylphenol which is useful as an intermediate for pharmaceuticals, agricultural chemicals, photographic drugs and the like. More specifically, by using a compound (host compound) that forms a host guest complex selectively with respect to m-ethylphenol (guest compound), m-ethylphenol is converted from an ethylphenol isomer mixture containing m-ethylphenol. The present invention relates to a method for separation and purification.

[0002]

2. Description of the Related Art Several methods for producing m-ethylphenol are known. An old example is the sulfonation of ethylbenzene (for example, JP-B-49-33192 and JP-B-49-33193). In this method, a sulfonic acid other than the m-form is hydrolyzed from the ethylbenzenesulfonic acid mixture, and the remaining m-form is alkali-fused. Further, using a specific aluminosilicate catalyst, m
A method of selectively decomposing p-ethylphenol in a mixture of-and p-ethylphenol to obtain residual m-ethylphenol has also been reported (Japanese Patent Publication No. 2-242).
59).

[0003] Further, a method by ethylation of phenol is also being studied. In this method, a mixture of o-, m-, and p-ethylphenol is obtained. After o-ethylphenol is separated by distillation, m-ethylphenol is separated and recovered by adsorption separation or the like.

[0004]

In the above-mentioned method for sulfonating ethylbenzene, sulfuric acid and sodium hydroxide, which are dangerous to handle, must be handled at a relatively high temperature, and a large amount of harmful wastewater is generated. .

A method using an aluminosilicate catalyst is as follows:
Since the reaction is performed at a high temperature of 450 ° C., there is a problem in reduction in yield due to thermal decomposition and operability.

In the method of separating and recovering m-ethylphenol by adsorption separation or the like, p-ethylphenol is not sufficiently separable, and the yield decreases when the separation rate is increased, and the purity decreases when the yield is increased. There was a problem.

An object of the present invention is to solve the above-mentioned 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 present inventors have intensively studied to develop means for solving the above-mentioned problems, and have conducted a separation using a host guest complex which is known as a technique for separating isomers of phenol compounds. Focusing on the method, a wide range of host compounds capable of selectively including m-ethylphenol as a guest compound was searched. 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, the present invention relates to a method for producing a m-ethylphenol-containing mixture of ethylphenol isomers by contacting the mixture with tetraphenylphosphonium bromide or 1,1-di (4-hydroxyphenyl) -cyclohexane.
The present invention relates to a method for separating m-ethylphenol, comprising precipitating an ethylphenol-containing substance and subjecting the same to solid-liquid separation.

The type of the ethylphenol isomer mixture to which the present invention can be applied is not particularly limited. Usually, m-ethylphenol is contained in an amount of about 40 to 95% by weight, preferably 65 to 95% by weight.
About 95%, about 5 to 60% of p-ethylphenol,
Preferably, about 5 to 30% is contained. Third
Components may be included, for example, about 0 to 20%, particularly about 0 to 10% of o-ethylphenol, about 0 to 5%, particularly about 0 to 3% of diethylphenol, and 0 to 10% of other phenols. %, Especially about 0 to 5%. O-form in a mixture of ethylphenol isomers,
The content of all ethylphenol isomers including the m- and p-forms is 85 to 100%, usually about 90 to 95%. Such an ethylphenol isomer mixture is usually in a liquid state at room temperature, and can be produced, for example, by sulfonation of ethylbenzene-alkaline melting, or phenol of ethylene or ethanol.

[0011] Tetraphenylphosphonium bromide can be easily obtained by reacting triphenylphosphine with phenylmagnesium bromide in ether, and is commercially available as an industrial chemical. It 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 its details are described in, for example, JP-A-62-263135. It is a white solid crystal at room temperature and has a melting point of 175 ° C or higher.

In the method of forming a host guest complex in the present invention, one of the above host compounds is added to a mixture of ethylphenol isomers to form a homogeneous phase.

The amount of the host compound to be added is about 0.05 to 5 moles, preferably about 0.2 to 2 moles, per mole of the ethylphenol isomer mixture. As a means for uniformly dissolving the host compound and the guest compound, m-ethylphenol, simple stirring may be sufficient in some cases, but heating is preferable for shortening the operation time. The heating temperature is not particularly limited as long as the m-ethylphenol of the guest compound does not remarkably evaporate and escape, but is usually 40 to 180 ° C, preferably 100 to 150 ° C.
The degree is appropriate. In the method of the present invention, a solvent can be used. When the solvent is a low-boiling solvent, the temperature is naturally lower than the boiling point of the low-boiling solvent. The boiling point at this time varies depending on the pressure of the system, and can be carried out under pressure as needed.

The temperature at which the complex crystal is precipitated may be room temperature, but the temperature should be lowered to room temperature or lower using a refrigerant. In the case of a crystal that is difficult to precipitate, the precipitation is accelerated by cooling to shorten the time required for the precipitation. It is also possible. In that case,-
It is preferable to lower the temperature to about 15 to + 30 ° C, preferably to -5 to + 15 ° C. The time required for the precipitation is not particularly limited, but is preferably short. 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.

In the method of the present invention, a solvent can be used. 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, the generation rate, and for facilitating the recovery of the complex from the system, and is not particularly necessary if it can be carried out without a solvent.

Means for solid-liquid separation of the precipitated complex crystal may be filtration or centrifugation. After separation, washing is performed if necessary. The washing may be appropriately selected from the above solvents.

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

As a method for obtaining m-ethylphenol from a substance containing m-ethylphenol as a host guest complex, a method in which m-ethylphenol as a guest compound is decomposed and vaporized 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 is about 300 ° C. or less, and may be any temperature at which the guest compound can be vaporized and distilled. Usually 100 to 250 ° C, preferably 150 to 20
0 ° C. is appropriate, and the reaction is performed under reduced pressure at which m-ethylphenol can be vaporized at the temperature.

[0020]

[Function] Separation by a host guest complex is a separation method utilizing the fact that another compound enters a vacancy of a three-dimensional structure formed by bonding a certain compound with a certain composition to form a specific crystal structure, Unlike distillation, it is a relatively easy physical separation method. A compound having a skeletal structure as a host compound,
The compound that has entered the vacancy is called a guest compound, and the host compound crystal that has incorporated the guest compound is separated from the system,
The target substance is obtained by re-decomposition.

The two host compounds used in the present invention, tetraphenylphosphonium bromide or 1,1-di
It is not clearly understood how any of (4-hydroxyphenyl) -cyclohexane acts at the stage of forming the host-guest complex, but at the stage of mixing the host compound and the guest compound, Forms crystals with a mixed stoichiometric ratio. The host compound is arranged and crystallized with certain vacancies, and a specific compound whose molecular size, electrical environment, etc. match the vacancies, m-ethylphenol is selectively taken in the present invention. It will be included. The incorporated host guest complex becomes a crystal and is easily separated from the solution.

The m-ethylphenol present in the separated complex crystals is present in the lattice of tetraphenylphosphonium bromide or 1,1-di (4-hydroxyphenyl) -cyclohexane via hydrogen bonds. Therefore, if this complex was heated, it was easily incorporated.
-Ethyl phenol can be driven out.

[0023]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 5.0 g of tetraphenylphosphonium bromide (11.
9mmol) and mixed ethylphenol (m-ethylphenol 67.0%, p-ethylphenol 25.0%,
2,6-diethylphenol 4.8%, others 3.2%
2.0 g (16% in terms of ethylphenol).
4 mmol) and 10 ml of acetone are added and dissolved at room temperature. When the solution was allowed to stand at room temperature for 12 hours, crystals were precipitated. The crystals were separated by filtration, washed with hexane, and weighed 2.7 g. This crystal
When heated under the conditions of 00 ° C./20 mmHg, m
0.6 g of ethylphenol was recovered. Analysis of this recovered product by gas chromatography revealed that 92.8% of m-ethylphenol and 6.0% of p-ethylphenol.
showed that.

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

Analysis of the recovered product by gas chromatography 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 ethyl phenol (the composition is the same as in Example 1) were used. Dissolve in solvent at 40 ° C. When the solution is allowed to stand at room temperature, crystals precipitate out soon. Therefore, the crystals were filtered, washed with hexane, and weighed 3.0 g.
When the crystals were heated under the condition of 200 ° C./20 mmHg, 0.85 g of m-ethylphenol was recovered. Analysis of this recovered product using a gas chromatogram showed 98.6% of m-ethylphenol and 1.3% of p-ethylphenol.

[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.

Continuing from the front page (72) Inventor Yuki Sekiguchi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Inside Adchemco Co., Ltd. JP 8-30776 (JP, A) JP-A-62-263135 (JP, A) JP-A 8-291096 (JP, A) JP-A 64-3135 (JP, A) JP-A 8-20551 (JP, A) , A) JP-A-8-245457 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 39/06 C07C 37/82 C07C 37/86

Claims (1)

(57) [Claims] 1. An ethylphenol isomer mixture containing m-ethylphenol is prepared by mixing tetraphenylphosphonium bromide or 1,1-di (4-hydroxyphenyl).
-A method for separating m-ethylphenol, which comprises contacting with cyclohexane to precipitate a substance containing m-ethylphenol, and subjecting the substance to solid-liquid separation.