JP2003252816A - Method for separating and purifying alkylphenol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently and highly purely separating and purifying a specific alkylphenol in a simple means. <P>SOLUTION: This method for separating and purifying the alkylphenol is characterized by comprising the first process for bringing a raw material mixture containing the alkylphenol into contact with a host compound to produce the complex containing a specific alkyl phenol as a guest compound, the second process for separating the complex from the raw material mixture left without forming the complex, and the third process for thermally decomposing the complex in the presence of a high boiling point medium oil to recover the specific target alkylphenol. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for separating and purifying an alkylphenol isomer useful as an intermediate for chemicals, pharmaceuticals, agricultural chemicals, and the like, and more specifically, a host-guest complex (hereinafter The present invention relates to a method for separating and purifying a specific alkylphenol, which utilizes formation of “complex” or “complex crystal”.

[0002]

A method for separating and purifying alkylphenols utilizing the formation of a complex is disclosed in, for example, JP-A-62-26.
Method for separating m-cresol disclosed in Japanese Patent No. 3135,
And m-shown in Japanese Patent Laid-Open No. 09-151146.
A method for separating and purifying a mixture of ethylphenol and p-ethylphenol is known.

[0003]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
2-263135, and Japanese Patent Laid-Open No. 09-1511.
According to the method disclosed in Japanese Patent Publication No. 46, etc., a complex selectively containing the specific alkylphenol can be obtained from a mixture containing the specific alkylphenol, but it is necessary to separate and recover the specific alkylphenol as the target from the complex. It is necessary to thermally decompose the complex at a high temperature of ~ 200 ° C.

For this reason, it is necessary to heat the complex to a predetermined temperature, but the complex is in a solid crystalline form, and the complex partially melts at the thermal decomposition temperature to form a paste. When the complex has a poor heat resistance and is industrially processed in a large amount, it takes a long time to heat the complex, the efficiency of separating and purifying the target product is low, and the quality of the separated purified product due to local overheating and the deterioration of the host compound There is a problem that deterioration occurs. Further, in order to alleviate this problem, when stirring is performed during the thermal decomposition of the complex, a special device capable of stirring the solid must be used, which causes a new problem that a large amount of power is required. .

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for separating and purifying a high-purity specific alkylphenol by a simple means and efficiently.

[0006]

[Means for Solving the Problems] From the complex formed by a host compound and an alkylphenol, the present inventors
When recovering the specific alkylphenol of interest,
When the thermal decomposition of the complex is carried out in a medium oil having a high boiling point, it can be handled as a slurry fluid that can be stirred by a normal device,
The inventors have found that a high heat transfer rate can be obtained, and completed the present invention.

In the present invention, the first step of bringing a raw material mixture containing an alkylphenol into contact with a host compound to form a complex containing a specific alkylphenol as a guest compound, and the complex and regardless of the complex formation The second step of separating the remaining raw material mixture and the complex,
A third step of thermally decomposing in the presence of a medium oil having a high boiling point to recover a specific alkylphenol which is a target product is provided, and a method for separating and purifying alkylphenols is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. Examples of the host compound used in the method of the present invention include di (4-hydroxyphenyl) methane, 2,2-di (4-hydroxyphenyl) propane, 1,1-di (4-hydroxyphenyl) cyclohexane and di ( Bisphenol type compounds such as 4-hydroxyphenyl) sulfone may be mentioned.
Among these, 1,1-di (4-hydroxyphenyl) cyclohexane has a high selectivity of complex formation with respect to alkylphenols and can be used particularly preferably. This 1,1-di (4-hydroxyphenyl) cyclohexane is industrially produced from cyclohexane and phenol, and can be easily obtained from the market. Details of the production method are described in, for example, JP-A-62-263.
No. 135 publication. This compound is a white crystal at room temperature and has a melting point of 175 ° C. or higher.

A mixture containing a specific alkylphenol to which the method of the present invention is applied and an organic substance other than the alkylphenol is a mixed carboxylic acid obtained by tar distillation, an oily component produced during coal gasification, an acidic oil component removed in a petroleum refining process, Alkylation reaction product of phenols, sulfonated alkali fusion product of alkylbenzene, toluene,
It can be obtained as a synthetic cresol produced by the cumene method from xylene, an isomer mixture of synthetic xylenol, or a distillation component thereof.

The mixture to be used in the method of the present invention includes a mixture of one kind of alkylphenol and an organic substance other than the alkylphenol, a mixture of different kinds of alkylphenol, a mixture of the same kind of alkylphenol isomers, and the like.
The method of the present invention is a separation of a heterogeneous alkylphenol mixture having a close boiling point, which is difficult to separate by conventional methods such as distillation,
It is more effective for separation of a mixture of homologous alkylphenol isomers. Examples of such separation and purification of a mixture containing an alkylphenol for which the method of the present invention is particularly useful include, for example, separation and purification of an isomer mixture of m-cresol and p-cresol, m-ethylphenol and p-ethylphenol. Separation and purification of the isomer mixture of the above, and separation and purification of the xylenol isomer mixture including 2,4-xylenol and 2,5-xylenol.

In addition to various alkylphenols, the mixture which is the object of the method of the present invention may contain other compounds. Examples of compounds other than this alkylphenol include unsubstituted phenol and naphthalene.
Impurities such as neutral oils such as methylnaphthalene may be mentioned. The total concentration of these compounds other than alkylphenol is usually 50% by weight or less of the raw material mixture, preferably 2%.
It is suitable to be 5% by weight or less, particularly preferably 10% by weight or less.

In the method of the present invention, the separation and purification of alkylphenols are carried out in three major steps. In the first step, a target material mixture containing a specific alkylphenol as a target is brought into contact with a host compound to form a complex containing a specific alkylphenol as a guest compound. At this stage, in the complex, a specific alkylphenol is incorporated as a guest compound according to the selectivity of the host compound for complex formation, and is present in the complex in high purity. On the other hand, in the raw material mixture remaining regardless of the complex formation, the concentration of the specific alkylphenol which is the target is reduced, and unnecessary components other than the target are concentrated.

In the subsequent second step, the complex crystals produced in the first step and the raw material mixture remaining regardless of the complex formation are separated. By this operation, at this stage, only the target specific alkylphenol is separated from the initial raw material mixture in the form of being incorporated in the complex.

Further, in the third step, the complex obtained in the second step is decomposed into a specific alkylphenol and a host compound to recover the specific alkylphenol as an intended product and also to regenerate and recover the host compound. . In the method of the present invention, the third step is carried out by a pyrolysis operation in a medium oil, whereby separation and purification can be carried out easily and efficiently. By repeating the above three steps, the specific alkylphenol which is the target can be industrially and efficiently separated and purified from the raw material mixture.

Each step will be described in more detail below. In the first step of the method of the present invention, a complex containing a specific alkylphenol as a guest compound is formed from a raw material mixture containing a specific alkylphenol and a host compound. As a method of forming this complex, a raw material mixture containing an alkylphenol, a host compound and, if necessary, a solvent are mixed, heated and dissolved to form a uniform solution, and then cooled to precipitate a complex, a raw material mixture. And a host compound are dissolved in a solvent, a method of removing a part of the solvent by distillation or the like to precipitate the complex, a method of dissolving the raw material mixture and the host compound in the solvent, and then cooling to precipitate the complex, After dissolving the raw material mixture and the host compound in a good solvent, a method of adding a poor solvent to precipitate the complex, after dissolving the raw material mixture and the host compound in a mixture of the good solvent and the poor solvent, the good solvent by distillation etc. Method of removing and precipitating complex, method of precipitating complex by dissolving host compound in raw material mixture and then cooling or adding poor solvent when raw material mixture is liquid , A raw material mixture or a solution, and a host compound in the solid state, or a method in which solid-liquid contacting with the formation of complexes with a mixed may be mentioned as examples. Among these methods, a method of mixing a raw material mixture and a host compound, heating and dissolving, and then cooling to precipitate a complex is common, and can be more preferably used. Will be described in detail.

The complex formation is preferably carried out in the presence of a solvent in order to control the crystal shape and production rate of the complex and to facilitate the recovery operation of the complex, but when the raw material mixture is liquid, When a raw material mixture is heated and melted, or when a solvent is not particularly required, it can be performed without a solvent.

When a solvent is used for complex formation, examples of the solvent include ethers such as diethyl ether, tetrahydrofuran and dioxane, esters such as methyl acetate and ethyl acetate, ketones such as acetone, butanone and methyl isobutyl ketone. , Halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, pentane, hexane, octane, decane, dodecane, tetradecane, hexadecane, octadecane,
Aliphatic hydrocarbons such as eicosane, docosane, cyclohexane, kerosene, liquid paraffin, poly α-olefin,
Examples thereof include aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene, isopropylnaphthalene, diisopropylnaphthalene, ethylbiphenyl, and a mixture thereof. In order to simplify the process, it is also preferable to use the same high-boiling medium oil used in the third process and the solvent at the time of complex formation. The amount of these solvents used is not particularly limited, but is generally about 10 to 100 parts by weight of the raw material mixture.
It is in the range of 1000 parts by weight.

The mixing ratio of the raw material mixture and the host compound at the time of complex formation is not particularly limited, but a general mixing ratio is 0.0
It is in the range of 5 to 10 mol, preferably 0.2 to 2 mol.

At the time of complex formation, the raw material mixture and the host compound are mixed and dissolved by heating at a temperature of usually 40 to 200 ° C.
The range of 80 to 160 ° C is preferable. Also,
The temperature at which the complex is deposited varies depending on the conditions such as the raw material mixture used and the solvent, but it is usually room temperature. If necessary, the temperature may be lower than room temperature by forced cooling or cooling with a refrigerant in order to increase the recovery amount of the complex, and in order to simplify the process, within a range where a sufficient recovery amount of the complex is obtained. The temperature may be room temperature or higher.

The operating pressure for forming the complex may be usually atmospheric pressure. When a solvent is used, it may be under pressure or under reduced pressure depending on its boiling point. The time required for complex formation varies depending on the scale to be carried out, the apparatus used, the heating and cooling conditions, etc., but is generally about 10 minutes to 48 hours.

Next, the second step will be described. In the second step, the complex crystals generated in the first step and the raw material mixture remaining regardless of the complex formation are separated. As a method for separating the complex and the remaining raw material mixture,
The method by solid-liquid separation and the method by distillation can be mentioned as an example.

In the solid-liquid separation method, the complex precipitated as a solid crystal and the raw material mixture or solvent remaining as a liquid may be separated by filtration or decantation. As the method, commonly used natural filtration, suction filtration, pressure filtration, centrifugal filtration, filter press, screw press, centrifugal separation, centrifugal decantation and the like can be used.

In order to improve the quality of the specific alkylphenol to be recovered, it is desirable that the complex obtained after the separation be washed with a solvent as necessary to more completely remove the remaining raw material components. The same solvent as that used in the first step can be used as the washing solvent.

In the separation method by distillation, by using a high vacuum, the distillation temperature is kept below the thermal decomposition temperature of the complex,
It is possible to distill off the residual raw material mixture and the solvent used in the first step regardless of the complex formation without losing the target compound incorporated as a guest compound in the complex. Further, in the distillation operation, in order to fluidize the contents and increase the efficiency of removing the remaining raw material mixture, it is desirable to use a medium oil and distill off the raw material mixture together with a part thereof.

The above-mentioned medium oil is preferably one which does not dissolve the complex under distillation conditions and has a boiling point equivalent to or higher than that of the raw material mixture. Examples include decane, dodecane, tetradecane, hexadecane, octadecane, eicosane, docosane, kerosene, liquid paraffin, aliphatic hydrocarbons such as poly-α-olefins, methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene, isopropylnaphthalene,
Examples thereof include aromatic hydrocarbons such as diisopropyl naphthalene and ethyl biphenyl, or a mixture thereof. The amount of the medium oil used is not particularly limited, but is generally about 10 to 100 per 100 parts by weight of the complex.
It is in the range of 0 parts by weight.

The pressure of the distillation operation is usually 5 torr or less,
It is preferably 1 torr or less, particularly preferably 0.5 to
The temperature is in the range of rr or lower, and the temperature is usually 120 ° C. or lower, preferably 100 ° C. or lower, particularly preferably 80 ° C. or lower. If the second step is carried out by a method by distillation, the operation can be performed in the same reactor as the first step or the third step, so that the separation and purification of the raw material mixture can be performed more simply and efficiently. be able to.

Next, the third step will be described. In the third step, the complex obtained in the second step is pyrolyzed in a medium oil to separate and recover a specific alkylphenol which is a target product and a host compound. In this thermal decomposition, the operation of simply heating only the complex as is conventionally known is because the solid crystal complex has poor heat transfer,
Especially when a large amount of treatment is carried out, a large amount of time is required for heating. In addition, there is a problem that local overheating occurs and the target substance or host compound is deteriorated, and further, the partially melted complex becomes a paste during thermal decomposition, making stirring difficult. To avoid the above problems,
In the method of the present invention, the thermal decomposition of the complex is carried out in a medium oil having a high boiling point,
The whole is done as a stirrable slurry fluid.

The thermal decomposition operation of the complex is carried out under reduced pressure, and the thermal decomposition temperature of the complex is set to be equal to or higher than the boiling point of the specific alkylphenol as the target product, and the target product is evaporated at the same time as the thermal decomposition of the complex is recovered as a distillation fraction. Operation becomes simple,
It is desirable because it can prevent the recombination of the target compound and the host compound. Further, it is also preferable to distill a part of the medium oil together with the target substance because the efficiency of recovering the target substance is improved.

The high boiling point medium oil to be used has a boiling point equal to or higher than that of the specific target alkylphenol, is easy to separate from the target, and is difficult to dissolve the complex below the thermal decomposition temperature of the complex. Is preferred. Examples include decane, dodecane, tetradecane, hexadecane,
Aliphatic hydrocarbons such as octadecane, eicosane, docosane, kerosene, liquid paraffin, and poly-α-olefins, aromatic hydrocarbons such as methylnaphthalene, dimethylnaphthalene, trimethylnaphthalene, isopropylnaphthalene, diisopropylnaphthalene, and ethylbiphenyl, or these A mixture etc. can be mentioned. The amount of the medium oil used is not particularly limited, but in general, the complex 1
It is in the range of 10 to 1000 parts by weight per 00 parts by weight.

The temperature for the thermal decomposition of the complex must be within the range in which decomposition of the complex easily proceeds and the target compound and host compound do not deteriorate. The temperature is usually 100 to 3
It is in the range of 00 ° C, preferably 120 to 250 ° C, particularly preferably 140 to 200 ° C.

The pressure during the thermal decomposition operation of the complex is preferably such that the thermal decomposition temperature of the complex can be maintained and that the thermal decomposition temperature of the complex is not lower than the boiling point of the target substance.
The pressure is generally in the range of 1 to 100 torr, though it cannot be generally stated depending on the type of the target oil or the medium oil used. The host compound is recovered as a residue after the thermal decomposition operation of the complex, and can be recycled to the first step and reused as it is.

The alkylphenol separated and recovered by the method of the present invention can be further purified and used by a general method such as distillation, crystallization and extraction.

[0033]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. In the text, “%” is based on weight unless otherwise specified. Example 1 <First Step> Mixed ethylphenol 3 containing 68.2% of m-ethylphenol, 30.0% of p-ethylphenol, and 1.8% of other components as a raw material mixture.
60.1 g was used. The raw material mixture, a host compound (1,1-di (4-hydroxyphenyl) cyclohexane) 400.2 g, and mesitylene 320.4 as a solvent.
g was taken in a 3 L three-necked flask equipped with a mechanical stirrer and a reflux condenser, mixed and heated to 150 ° C. to be dissolved to obtain a uniform solution. This solution was allowed to stand at room temperature for a whole day and night to precipitate a complex crystal, which was made into a slurry. In this step, the host compound and m-ethylphenol form a complex of about 1 molecule to 1 molecule, and about 74% of the m-ethylphenol forms a complex.

<Second Step> The slurry is suction filtered to separate the raw material mixture remaining regardless of complex formation, thoroughly washed with hexane, and then air-dried to give 560.4 g of host-guest complex crystals. Got When this complex crystal was analyzed by gas chromatography, it contained 32.1% ethylphenol content.

<Third Step> Of the above complex crystals, 15
0.1 g was taken into a 500 mL three-necked flask equipped with a mechanical stirrer and a branch tube for distillation, and 100.2 g of diisopropylnaphthalene was added as a medium oil,
The mixture was heated under reduced pressure of torr using a 200 ° C. oil bath to thermally decompose the complex, and 53.2 g of a distillate (a mixture of a solvent and m-ethylphenol) was recovered. When this distillate was analyzed by gas chromatography and quantified, it contained 46.0 g of ethylphenol,
The recovery rate of ethylphenol from the complex crystals was 95%. When the composition of the recovered ethylphenol was analyzed by gas chromatography, the purity of m-ethylphenol was 99.5% or higher, and p-ethylphenol was not detected.

Example 2 150.0 g of the complex crystals produced in Example 1 were placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a distillation branch tube, and tetradecane 10 was used as a medium oil.
0.2 g was added, and the mixture was heated under a reduced pressure of 90 torr using an oil bath at 200 ° C. to thermally decompose the complex.
1.8 g of distillate (mixture of solvent and m-ethylphenol) was recovered. When this distillate was analyzed and quantified by gas chromatography, it contained 47.7 g of ethylphenol, and the recovery rate of ethylphenol from the complex crystals was 99%. In addition, when the composition of this recovered ethylphenol was analyzed by gas chromatography,
The purity of m-ethylphenol is 99.5% or more,
No p-ethylphenol was detected.

Example 3 150.3 g of the complex crystal produced in Example 1 was placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a distillation branch tube, and octadecane 10 was used as a medium oil.
0.6 g was added, and the mixture was heated under reduced pressure of 90 torr using an oil bath at 200 ° C. to thermally decompose the complex.
9.2 g of distillate (mixture of solvent and m-ethylphenol) was recovered. When this distillate was analyzed by gas chromatography and quantified, it contained 47.2 g of ethylphenol, and the recovery rate of ethylphenol from the complex crystals was 98%. In addition, when the composition of this recovered ethylphenol was analyzed by gas chromatography,
The purity of m-ethylphenol is 99.5% or more,
No p-ethylphenol was detected.

Example 4 <First step> As a raw material mixture, 2,4-xylenol 30.6% and 2,5-xylenol 67.7% were used.
Mixed xylenol 13 containing 1.7% of other ingredients
5.1 g was used. A 3 L three-necked flask equipped with this raw material mixture, 150.0 g of a host compound (1,1-di (4-hydroxyphenyl) cyclohexane), and 120.4 g of decane as a solvent, and a mechanical stirrer and a reflux condenser. , Mixed and heated to 150 ° C. to dissolve to obtain a uniform solution. This solution was allowed to stand at room temperature for a whole day and night to precipitate a complex crystal, which was made into a slurry. In this step, the host compound and 2,5-xylenol form a complex of about 1 molecule to 1 molecule, and about 75% of the 2,5-xylenol forms a complex.

<Second Step> The above slurry is suction-filtered to separate the raw material mixture remaining regardless of complex formation, thoroughly washed with hexane, and then air-dried to give 210.8 g of host-guest complex crystals. Got When this complex crystal was analyzed by gas chromatography, it contained 32.3% of xylenol content.

<Third Step> Of the above complex crystals, 15
0.1 g was taken in a 500 mL three-necked flask equipped with a mechanical stirrer and a branch tube for distillation, and 100.6 g of diisopropylnaphthalene was added as a medium oil,
The mixture was heated under reduced pressure of torr using a 200 ° C. oil bath to thermally decompose the complex, and 54.2 g of a distillate (a mixture of a solvent and 2,5-xylenol) was recovered. When this distillate was analyzed and quantified by gas chromatography, 46.5 g of xylenol was contained, and the recovery rate of xylenol from the complex crystals was 96%. Further, when the composition of the recovered xylenol was analyzed by gas chromatography, the purity of 2,5-xylenol was found to be 9
It was 9.5% or more, and 2,4-xylenol was not detected.

Example 5 <First Step> As a raw material mixture, m-cresol 8 was used.
135.3 g of mixed cresol containing 9.2%, p-cresol 10.4%, and other components 0.4% was used. This raw material mixture and a host compound (1,1-di (4-hydroxyphenyl) cyclohexane) 150.
0 g and 120.4 g of mesitylene as a solvent were placed in a 3 L three-necked flask equipped with a mechanical stirrer and a reflux condenser, mixed, heated to 150 ° C. and dissolved to give a uniform solution. This solution was allowed to stand at room temperature for a whole day and night to precipitate a complex crystal, which was made into a slurry. In addition, in this step, the host compound and the cresol component form a complex of about 1 molecule to 1 molecule.

<Second Step> The above slurry is suction-filtered to separate the raw material mixture remaining regardless of complex formation, thoroughly washed with hexane, and then air-dried to obtain 207.7 g of host-guest complex crystals. Got When this complex crystal was analyzed by gas chromatography, it contained 30.1% of cresol content.

<Third Step> Of the above complex crystals, 15
0.1 g was placed in a 500 mL three-necked flask equipped with a mechanical stirrer and a branch tube for distillation, 100.2 g of diisopropylnaphthalene was added as a medium oil, and 90 t was added.
The mixture was heated under reduced pressure of orr using a 200 ° C. oil bath to thermally decompose the complex, and 50.2 g of a distillate (a mixture of a solvent and m-cresol) was recovered. When this distillate was analyzed and quantified by gas chromatography, 43.
It contained 3 g of cresol, and the recovery rate of cresol from the complex crystals was 96%. When the composition of this recovered cresol was analyzed by gas chromatography, the concentration of m-cresol was 97% and the concentration of p-cresol was 3%.

Example 6 <First Step> As a raw material mixture, 68.2% of m-ethylphenol, 30.0% of p-ethylphenol, and
90.2 g of mixed ethylphenol containing 1.8% of other components was used. This raw material mixture, 100.1 g of a host compound (1,1-di (4-hydroxyphenyl) cyclohexane), 120.5 g of diisopropylnaphthalene as a solvent, a mechanical stirrer and a distillation branch tube were installed in three 500 mL volumes. Take in a mouth flask,
The mixture was mixed and heated to 150 ° C. to be dissolved to obtain a uniform solution. The solution was allowed to stand overnight at room temperature with gentle stirring to precipitate complex crystals, which was made into a slurry.

<Second Step> The above slurry was heated in an oil bath at 90 ° C. under a reduced pressure of 0.2 torr while stirring, and 59.3 g of distillate (a raw material mixture remaining regardless of complex formation) was added. ) Was recovered. When this distillate was analyzed by gas chromatography and quantified, it contained 47.3 g of ethylphenol.

<Third Step> While continuing the stirring of the slurry, the pressure is 90 torr and the oil bath temperature is 200.
The complex was thermally decomposed at ℃ and 50.1 g of a distillate (a mixture of a solvent and m-ethylphenol) was recovered. When this distillate was analyzed and quantified by gas chromatography, it contained 41.5 g of ethylphenol.
The solvent and ethylphenol were separated to recover ethylphenol. When the composition of this recovered ethylphenol was analyzed by gas chromatography, the purity of m-ethylphenol was 99.5% or higher, and p-ethylphenol was not detected.

Example 7 <First Step> As a raw material mixture, 68.2% of m-ethylphenol, 30.0% of p-ethylphenol, and
90.2 g of mixed ethylphenol containing 1.8% of other components was used. 500 mL three provided with the raw material mixture, a host compound (1,1-di (4-hydroxyphenyl) cyclohexane) 100.0 g, and diisopropylnaphthalene 60.1 g as a solvent, and a mechanical stirrer and a branch pipe for distillation. The mixture was placed in a necked flask, mixed, and heated to 150 ° C. to dissolve the mixture into a uniform solution. The solution was allowed to stand overnight at room temperature with gentle stirring to precipitate complex crystals, which was made into a slurry.

<Second Step> To the above slurry, 60.1 g of dodecane was added and heated with stirring in an oil bath at 90 ° C. under a reduced pressure of 0.2 torr to obtain 90.8 g of distillate (for complex formation). The raw material mixture remaining regardless of the above was recovered. When this distillate was analyzed and quantified by gas chromatography, it contained 45.3 g of ethylphenol.

<Third Step> While continuing the stirring of the slurry, the pressure is 90 torr and the oil bath temperature is 200.
The complex was pyrolyzed at ℃ and 60.3 g of a distillate (a mixture of a solvent and m-ethylphenol) was recovered. When this distillate was analyzed and quantified by gas chromatography, it contained 43.4 g of ethylphenol.
Furthermore, 300 mL of 10% NaO was added to the collected distillate.
Extracted with aqueous H solution. The aqueous layer was acidified with sulfuric acid and then extracted with 200 mL of toluene. The toluene layer was collected, concentrated, and distilled under reduced pressure to obtain an ethylphenol content of 36.3 g.
Was recovered. When the composition of this recovered ethylphenol was analyzed by gas chromatography, the purity of m-ethylphenol was 99.5% or higher, and p-ethylphenol was not detected. The above 43.4 g and the above 3
The difference of 6.3 g is a subsequent operational loss.

[0050]

As described above, according to the present invention, a high-purity specific alkylphenol can be separated and purified by a simple means.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07C 39/17 C07C 39/17 F term (reference) 4H006 AA02 AC26 AC93 AD11 AD17 AD33 BB11 BC10 BD70 FC22 FC52 FE13

Claims (9)

[Claims] 1. A first step of contacting a raw material mixture containing an alkylphenol with a host compound to form a host-guest complex containing a specific alkylphenol as a guest compound, the host-guest complex, and host-guest complex formation. Irrespective of the second step of separating the residual raw material mixture, and the third step of thermally decomposing the host-guest complex in the presence of a medium oil having a high boiling point to recover a specific alkylphenol as a target. And a step of separating and purifying alkylphenols. 2. The method according to claim 1, wherein the host compound is 1,1-di (4-hydroxyphenyl) cyclohexane. 3. In the third step, recovery of a specific alkylphenol, which is a target substance dissociated by thermal decomposition,
The method according to claim 1, which is carried out by distillation. 4. The method according to claim 1, wherein in the second step, the raw material mixture remaining regardless of host-guest complex formation is separated and removed by filtration or distillation. 5. The method according to claim 4, wherein the residual raw material mixture is distilled off at a temperature not higher than the thermal decomposition temperature of the host-guest complex regardless of formation of the host-guest complex. 6. The method according to claim 4, wherein the distillation of the raw material mixture remaining regardless of the formation of the host-guest complex is carried out in the presence of a medium oil. 7. The method according to claim 1, wherein the target alkylphenol is an isomer of cresol, an isomer of ethylphenol or an isomer of xylenol. 8. The method according to claim 1, wherein the raw material mixture containing alkylphenols is a isomer mixture of cresol, an isomer mixture of ethylphenol, or an isomer mixture of xylenol. 9. The method according to claim 1, wherein the raw material mixture containing alkylphenols is mixed carboxylic acid obtained by tar distillation or its distillation component.