JP2003146923A - Method for producing hydroxystyrene solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a hydroxystyrene solution, by which the highly pure hydroxystyrene solution having a small ethylphenol content can be produced from a mixture containing the hydroxystyrene and the ethylphenol in a simple operation. SOLUTION: This method for producing the hydroxystyrene solution is characterized by distilling the mixture containing the hydroxystyrene and the ethylphenol in the presence of a polyhydric alcohol liquid at 20 deg.C and/or its derivative to remove the ethylphenol, thereby obtaining the polyhydric alcohol and/or its derivative solution of the hydroxystyrene as the residue.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a solution of hydroxystyrene having a low content of ethylphenol from a mixture containing hydroxystyrene and ethylphenol. Hydroxystyrene is a compound useful as a raw material for paints, semiconductor materials and the like having excellent heat resistance and moisture resistance.

[0002]

2. Description of the Related Art Conventionally, hydroxystyrene can be produced by recovery from natural products, decomposition reaction of hydroxycinnamic acid or bis (hydroxyphenyl) ethane, dehydrogenation reaction of ethylphenol and the like. In any case, a mixture containing impurities such as unreacted raw materials and various by-products in addition to the desired hydroxystyrene is obtained. Therefore, a purification step is necessary to obtain high-purity hydroxystyrene from which impurities have been removed from the mixture. However,
Hydroxystyrene is a compound that is very easily polymerized, and since polymerization occurs immediately under high temperature conditions, a purification method that requires heating such as distillation has been regarded as inappropriate.

Conventionally, as a method of removing impurities from a mixture as described above to produce high-purity hydroxystyrene, the mixture is dissolved in a specific solvent, for example, toluene, and the resulting solution is treated with a water-soluble alcohol. In the coexistence, while refluxing with an extraction device having a reflux section, an alkaline aqueous solution is used as an extractant, and countercurrent liquid-liquid extraction is performed to obtain impurities of high-purity hydroxystyrene as a toluene solution is known. (Japanese Patent Laid-Open No. 53-7629).

[0004]

However, the above-mentioned extraction method requires complicated equipment and facilities, etc. Further, an alkaline aqueous solution is used as an extracting agent to convert phenols into alkali metal salts, and free phenols are re-dissolved. In order to obtain the product, there is a problem that it is necessary to use an acid, a large amount of inorganic salt waste liquid is generated, and the process is complicated. An object of the present invention is to provide a method capable of producing high-purity hydroxystyrene by a simple operation.

[0005]

Means for Solving the Problems The present inventor has conducted extensive studies in order to solve the above problems. As a result, a mixture containing hydroxystyrene and ethylphenol was added,
Distillation at 20 ° C. in the presence of polyhydric alcohol and / or its derivatives makes it possible to distill off and remove ethylphenol while inhibiting the polymerization of hydroxystyrene, and the content of ethylphenol as a residue. The inventors have found that a solution of a polyhydric alcohol and / or a derivative thereof containing high-purity hydroxystyrene with a small amount of hydrogen can be obtained, and have completed the present invention.

That is, according to the present invention, a mixture containing hydroxystyrene and ethylphenol is distilled at 20 ° C. in the presence of a polyhydric alcohol and / or a derivative thereof to distill ethylphenol, and the residue is used as a residue. The present invention relates to a method for producing a hydroxystyrene solution, which comprises obtaining a solution of a polyhydric alcohol containing hydroxystyrene and / or a derivative thereof.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As the mixture containing hydroxystyrene and ethylphenol in the present invention, those obtained by a conventionally known method can be used. Preferably, the one obtained by a method of dehydrogenating ethylphenol in the presence of a dehydrogenation catalyst (Japanese Patent Publication No. 53-43491) is used. 2-hydroxystyrene, 3-hydroxystyrene and 4-hydroxystyrene are respectively produced from 2-ethylphenol, 3-ethylphenol and 4-ethylphenol by the dehydrogenation reaction,
A mixture is obtained, each containing the desired hydroxystyrene and unreacted ethylphenol. Further, the mixture containing hydroxystyrene and ethylphenol contains other phenols of hydroxystyrene and ethylphenol, for example, impurities derived from ethylphenol as a raw material used for the above dehydrogenation and phenols as a by-product of the reaction. May be.

In the mixture containing hydroxystyrene and ethylphenol used in the present invention, the content ratio of both is not particularly limited, but when the content of hydroxystyrene is small, the amount of ethylphenol distilled out is large,
Since the time required for distillation becomes long, the chance of polymerization of hydroxystyrene increases, and the recovery rate of hydroxystyrene may decrease. Therefore, the higher the content of hydroxystyrene, the shorter the distillation time and the more efficient the distillation.

The polyhydric alcohol and its derivative which are liquid at 20 ° C. used in the present invention are preferably alkylene glycol, its ether and / or its ester, and more preferably the general formula (1):

[0010]

[Chemical 2] (In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group or an acyl group, X represents an alkylene group having 2 to 5 carbon atoms, and n is 1
Is an integer of ˜3. ) At least one alkylene glycol selected from the group consisting of compounds represented by the formula [] is hereinafter referred to as alkylene glycol (1). ].

Examples of the alkyl group represented by R ¹ and R ² in the above general formula (1) include a linear or branched alkyl group having 1 to 10 carbon atoms, preferably a methyl group, 1 to 4 carbon atoms such as ethyl, propyl and butyl groups
Is a linear or branched alkyl group. Further, examples of the aralkyl group represented by R ¹ and R ² include a benzyl group and a phenethyl group, and a benzyl group is preferable. Further, as the acyl group represented by R ¹ and R ² , for example, an alkylcarbonyl group having 2 to 7 carbon atoms such as an acetyl group, an arylcarbonyl group such as a benzoyl group,
Examples thereof include an aralkylcarbonyl group such as a benzylcarbonyl group, and an acetyl group is preferable.

Of the above alkylene glycols (1), those having a vapor pressure of 5300 Pa or less at 100 ° C. are particularly preferable. Examples of the compound include diethylene glycol di-n-butyl ether, diethylene glycol mono-n-butyl ether acetate and diethylene glycol mono. n-ethyl ether acetate, diethylene glycol mono n-butyl ether, diethylene glycol diacetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tripropylene glycol monomethyl ether,
Examples thereof include ethylene glycol di-n-butyl ether and ethylene glycol benzyl ether.

The amount of the polyhydric alcohol and / or its derivative which is liquid at 20 ° C. is usually 0.1 to 30 parts by weight, preferably 0.5 to 10 parts by weight based on 1 part by weight of the total of hydroxystyrene and ethylphenol. Parts by weight.

In the present invention, a mixture containing hydroxystyrene and ethylphenol is distilled at 20 ° C. in the presence of a liquid polyhydric alcohol and / or a derivative thereof to distill ethylphenol, and ethylphenol is used as a residue. A solution of a polyhydric alcohol and / or its derivative containing hydroxystyrene having a low content of is obtained.

The removal of ethylphenol in the present invention is carried out by charging a mixture containing hydroxystyrene and ethylphenol in a distillation kettle together with a liquid polyhydric alcohol and / or a derivative thereof at 20 ° C., and carrying out a distillation operation as it is to carry out ethyl acetate. Phenol may be distilled off. 20 ° C
As a liquid polyhydric alcohol and / or its derivative,
For example, when an alkylene glycol (1) having a vapor pressure of 5300 Pa or less at 100 ° C. is used, ethylphenol is first distilled alone, and then ethylphenol and alkylene glycols (1) having the above vapor pressure are produced. Distill as a mixture. When using the alkylene glycols (1) having the above vapor pressure,
First, a part of the total amount used was charged into a distillation still together with a mixture containing hydroxystyrene and ethylphenol to start distillation, and distillation of ethylphenol alone was completed, and ethylphenol and polyhydric alcohol and / or liquid at 20 ° C. Alternatively, a high-purity ethylphenol can be recovered by continuously or intermittently adding the rest from the top of the distillation column or the like before distilling a mixture with the derivative thereof, and continuing the distillation. Then, by distilling and removing the ethylphenol as described above, a solution of the polyhydric alcohol and / or its derivative which is liquid at 20 ° C. containing hydroxystyrene having a small content of ethylphenol as a residue is obtained. .

As the polyhydric alcohol and / or its derivative which is liquid at 20 ° C., the vapor pressure at 100 ° C. of the alkylene glycols represented by the above general formula (1) is 5
When a compound of 300 Pa or less is used, a polyhydric alcohol having a higher boiling point and / or a derivative thereof, such as polyethylene glycol or glycerin, is used together to further improve the effect of preventing the polymerization of hydroxystyrene.

Since hydroxystyrene is extremely easy to polymerize under high temperature conditions, in the distillation for distilling the ethylphenol, the pressure is 8,000 Pa or less,
It is preferable to distill p-ethylphenol while keeping the pressure at 4000 Pa or lower and keeping the liquid temperature in the distillation pot at 200 ° C. or lower, preferably 170 ° C. or lower. Pressure is 8
If it is higher than 000 Pa, the temperature in the distillation pot becomes high, hydroxystyrene is likely to be polymerized, and the recovery rate may decrease.

In the distillation for distilling the ethylphenol, the reflux ratio is preferably 20 or less, more preferably 10 or less. If the reflux ratio is greater than 20, distillation will take a long time, and the hydroxyphenol will be heated for a long time, increasing the chances of polymerization, which is not preferable.

The distillation equipment is not particularly limited and may be either continuous type or batch type, and the distillation column may be a precision distillation column such as a packed column or a plate column.

When the distillation is carried out in this way to distill off the ethylphenol, a solution of the polyhydric alcohol and / or its derivative which is liquid at 20 ° C. containing hydroxystyrene having a low content of ethylphenol as a residue is obtained.
Further, since the decomposition of hydroxystyrene can be suppressed by the distillation, hydroxystyrene is recovered in the above residue in a high yield.

By distilling the residue obtained by the above-mentioned distillation method with a thin-film distillation apparatus or the like, a solution of the polyhydric alcohol and / or its derivative which is liquid at 20 ° C. and further containing highly purified hydroxystyrene is obtained. To be

[0022]

EXAMPLES Examples of the present invention will be shown below, but the invention is not limited to these examples.

Reference Example 1 A mixture of p-hydroxystyrene and p-ethylphenol was obtained as follows. Vertical quartz reaction tube (inner diameter 2
Porcelain Raschig rings (outer diameter 6 mm, 6 mm in length, 500 mm in length) as a pre-evaporation zone for p-ethylphenol
80 ml (length 6 mm) was filled, and 250 ml of a catalyst (tin oxide) was filled in the lower portion as a reaction zone. An annular electric furnace was used to control the evaporation preheat zone and the reaction zone to be maintained at 460 ° C. from the outside of the reaction tube. From the top of the reaction tube, p-ethylphenol, toluene, cyclohexane, water and nitrogen [p-ethylphenol / toluene / cyclohexane / water / nitrogen (molar ratio) = 1 / 0.7 / 0.7 / 1
0/2] was supplied to guide these mixed gases onto the catalyst. The liquid hourly space velocity of p-ethylphenol (LH
SV) was adjusted to 0.3 / hour. The gaseous reaction product flowing out from the reaction tube was led to a condenser cooled with ice water to obtain a condensate. The composition of the obtained condensate was as follows.

[0024] p-Hydroxystyrene 3.0% by weight p-ethylphenol 25.1% by weight Toluene 15.3% by weight Cyclohexane 14.0% by weight Water 42.6% by weight

The contents of p-hydroxystyrene, p-ethylphenol, cyclohexane and toluene were measured by gas chromatography, and the content of water was measured by a Karl Fischer moisture meter.

The condensate obtained above is separated into an oil layer and a water layer with a separating funnel, and the resulting oil layer is subjected to a rotary evaporator under reduced pressure of 6000 Pa to 600 Pa and a light boiling component at around 25 ° C. Of toluene and cyclohexane were distilled off to obtain a mixture of p-hydroxystyrene and p-ethylphenol as a residue [p-hydroxystyrene / p-ethylphenol (weight ratio) = 10.
7 / 89.3].

Example 1 To 200.0 g of the residue obtained in the above Reference Example was added 300.0 g of diethylene glycol di-n-butyl ether, and a normal glass precision distillation column having a column diameter of 20 mm and a theoretical plate number of 40 was used and 400 Pa. Under reduced pressure, the reflux ratio was maintained at 5 to distill p-ethylphenol. Distillation of p-ethylphenol required 9 hours, and the liquid temperature in the distillation pot during this distillation was 140 to 145 ° C. As a result, first, a fraction of 100% pure p-ethylphenol was obtained with a recovery rate of 78%, and then the remaining 22% p-ethylphenol was obtained.
A mixture of ethylphenol and diethylene glycol di-n-butyl ether (p-ethylphenol concentration: 14
% By weight). The composition of the residue at this time is p-
Hydroxystyrene 14.1% by weight, p-ethylphenol 0.1% by weight, high boiling point component 2.4% by weight, diethylene glycol di-n-butyl ether 83.4% by weight [p-hydroxystyrene / p-ethylphenol ( (Weight ratio) = 99.3 / 0.7], and the recovery rate of p-hydroxystyrene was 94.0%.

The above residue was mixed with 0.5 part by weight of PEG 600 per 1 part by weight thereof, and the resulting mixture was heated at a temperature of 1 Pa under a reduced pressure of 400 Pa by a thin film distillation apparatus.
Distillation was performed at 10 ° C. at a feed rate of the mixture of 40 g / hr to remove high boiling components. The composition of the distillate was 16.5% by weight of p-hydroxystyrene, 0.1% by weight of p-ethylphenol, and 8% of diethylene glycol di-n-butyl ether.
It was 3.4% by weight [p-hydroxystyrene / p-
Ethylphenol (weight ratio) = 99.4 / 0.6]. The recovery rate of p-hydroxystyrene in this thin film distillation was 97.4%.

Example 2 p-Ethylphenol was distilled off in the same manner as in Example 1 except that diethylene glycol di-n-butyl ether was replaced with diethylene glycol mono-n-butyl ether acetate. Distillation of p-ethylphenol required 11 hours, and the liquid temperature in the distillation pot during this distillation was 140 to 148 ° C. As a result, first, the fraction of p-ethylphenol having a purity of 100% was adjusted to 58%.
Of p-ethylphenol and the remaining 42% of p-ethylphenol in a mixture with diethylene glycol mono-n-butyl ether acetate (p-ethylphenol concentration: 2).
1% by weight). The composition of the residue at this time is p
-Hydroxystyrene 14.5% by weight, p-ethylphenol 0.1% by weight, diethylene glycol mono-n-
Butyl ether acetate 85.4% by weight [p-
Hydroxystyrene / p-ethylphenol (weight ratio)
= 99.3 / 0.7], the recovery rate of p-hydroxystyrene was 60%.

Example 3 p-Ethylphenol was distilled out in the same manner as in Example 1 except that the degree of vacuum at the time of distilling out p-ethylphenol was changed to 4000 Pa. It took 8 hours to distill off p-ethylphenol, and the liquid temperature in the distillation pot during this distilling was 159 to 163 ° C. As a result, first, a fraction of p-ethylphenol having a purity of 100% was obtained with a recovery rate of 78%, and then the remaining 22% of p-ethylphenol was mixed with diethylene glycol mono-n-butyl ether acetate (p-ethylphenol). Concentration: 14% by weight). The composition of the residue at this time was 7.7% by weight of p-hydroxystyrene, 0.1% by weight of p-ethylphenol, and 92.2% by weight of diethylene glycol mono-n-butyl ether acetate [p-hydroxystyrene / p. -Ethylphenol (weight ratio) = 9
8.6 / 1.4], the recovery rate of p-hydroxystyrene was 75%.

Reference Example 2 The residue, which is a mixture of p-hydroxystyrene and p-ethylphenol obtained in Reference Example 1, was heated to 120 ° C. under normal pressure.
When kept at 94%, 94% of p-hydroxystyrene polymerized.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuhide Matsubara             2-12-13 West Nishi, Joto-ku, Osaka City, Osaka Prefecture               Koei Chemical Industry Co., Ltd. F-term (reference) 4H006 AA02 AD11 BB14 BB15 BB17                       BB49 FC52 FC74 FE13

Claims (6)

[Claims] 1. A mixture containing hydroxystyrene and ethylphenol is distilled at 20 ° C. in the presence of a polyhydric alcohol and / or a derivative thereof to distill ethylphenol, and the residue contains hydroxystyrene. A method for producing a hydroxystyrene solution, which comprises obtaining a solution of a polyhydric alcohol and / or a derivative thereof. 2. The method according to claim 1, wherein the polyhydric alcohol and / or its derivative is alkylene glycol, its ether and / or its ester. 3. A polyhydric alcohol and / or its derivative is represented by the general formula (1): (In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group or an acyl group, X represents an alkylene group having 2 to 5 carbon atoms, and n is 1
Is an integer of ˜3. The method according to claim 1, which is at least one alkylene glycol selected from the group consisting of compounds represented by 4. The method according to claim 3, wherein the at least one alkylene glycol is a compound having a vapor pressure at 100 ° C. of 5300 Pa or less. 5. The polyhydric alcohol and / or its derivative is diethylene glycol di-n-butyl ether, diethylene glycol mono-n-butyl ether acetate,
Diethylene glycol mono-n-ethyl ether acetate, diethylene glycol mono-n-butyl ether, diethylene glycol diacetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene glycol di-n-butyl ether and ethylene glycol benzyl ether The method according to claim 1, wherein the method is at least one compound selected from the group. 6. The method according to claim 1, wherein the polyhydric alcohol and / or its derivative is used in an amount of 0.1 to 30 parts by weight based on 1 part by weight of the total of ethylphenol and hydroxystyrene.