JP2012072073A - Method for purification of dihydroxybenzene, and method for production of dihydroxybenzene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for purification of dihydroxybenzene which can effectively remove hydroxyacetophenone.SOLUTION: The method for purification of dihydroxybenzene (hereafter abbreviated as DB) includes: a first extracting process for obtaining a first fraction 5 containing DB, etc., by adding water 2 to crude DB 1, then contacting with extraction solvent (I) to extract; a distillation process for distilling the first fraction to separate a third fraction 7 containing water, etc., and a fourth fraction containing DB, etc., then separating purified DB and a sixth fraction 10 DB containing concentrated hydroxyacetophenone by distillation of the fourth fraction 8; an oil-water separation process for obtaining the seventh fraction 11 containing ketones by oil-water separation of the third fraction; a second extraction process for obtaining a ninth fraction 16 containing DB and water by adding water to the sixth fraction and contacting with the seventh fraction and then extracting; and a recovery process for supplying the ninth fraction obtained in the second extraction process to an inlet of the first extraction process.

Description

  The present invention relates to a method for purifying dihydroxybenzene and a method for producing dihydroxybenzene, which can efficiently remove hydroxyacetophenone contained in dihydroxybenzene.

Dihydroxybenzene typified by resorcinol is produced by a method including a step of oxidizing diisopropylbenzene and a step of decomposing di (2-dihydroperoxy-2-propyl) benzene. The thus produced dihydroxybenzene contains isopropylphenol, hydroxyacetophenone, and the like as trace amounts of impurities. On the other hand, dihydroxybenzene is required to have a high level of product purity depending on the application, and a purification method for obtaining highly purified dihydroxybenzene has been developed (for example, see Patent Document 1).
As a method for removing such impurities, extraction separation using a mixed extract obtained by adding a ketone to an aromatic hydrocarbon is used. For example, Patent Document 2 discloses a process of oxidizing diisopropylbenzene and di (2- The crude dihydroxybenzene obtained from the process including the step of decomposing dihydroperoxy-2-propyl) benzene is subjected to distillation to obtain a section containing acetone from the low boiling side and a section containing dihydroxybenzene from the high boiling side. Step (first step), subjecting the section containing dihydroxybenzene obtained in the first step to distillation, obtaining a section containing dihydroxybenzene from the low boiling side, and obtaining a section containing heavy components from the high boiling side ( 2nd step), after adding water to the section containing dihydroxybenzene obtained in the 2nd step, contact with toluene and ketones and subject to extraction. A process that separates the water phase containing water and the oil phase containing impurities (third process), and the water phase containing dihydroxybenzene obtained in the third process is subjected to distillation, and the section containing dihydroxybenzene and the section containing water A method for removing impurities in dihydroxybenzene is described, which includes a step (fourth step) for obtaining.

Japanese Patent Publication No. 61-18537 JP 2004-123600 A

However, in the method described in Patent Document 2, although isopropylphenol can be effectively removed, a mixed extract obtained by adding a ketone such as methyl isobutyl ketone to an aromatic hydrocarbon such as toluene is dihydroxy. When contacted with an aqueous benzene solution, if the concentration of dihydroxybenzene in the aqueous solution is high, ketones move into the aqueous solution and the ability to remove hydroxyacetophenone into the extraction solvent phase decreases, whereas the concentration of dihydroxybenzene in the aqueous solution If it is low, excessive energy is required to separate dihydroxybenzene and water, and therefore further improvement has been demanded in terms of efficiently removing hydroxyacetophenone.
Under such circumstances, the problem to be solved by the present invention is to provide a method for purifying dihydroxybenzene and a method for producing dihydroxybenzene, which can efficiently remove hydroxyacetophenone contained in dihydroxybenzene.

That is, the present invention is a method for purifying dihydroxybenzene, which obtains purified dihydroxybenzene from crude dihydroxybenzene containing isopropenylphenol and hydroxyacetophenone as impurities, and includes the following first extraction step, the following distillation step, and the following oil-water separation. A dihydroxybenzene concentration in a dihydroxybenzene aqueous solution in the following first extraction step and the following second extraction step, which includes the steps, the following second extraction step and the following recovery step, according to the method for purifying dihydroxybenzene satisfying the following formula (1) Is.
First extraction step: After adding water to the crude dihydroxybenzene to obtain a dihydroxybenzene aqueous solution A, it is brought into contact with an extraction solvent (I) containing aromatic hydrocarbons and ketones and subjected to extraction to obtain dihydroxybenzene, hydroxy Separating into a first section containing acetophenone, ketones and water, and a second section containing isopropenylphenol and aromatic hydrocarbons Distillation process: The first section obtained in the first extraction process is subjected to distillation, Separating into a third section containing water and ketones and a fourth section containing dihydroxybenzene and hydroxyacetophenone, then subjecting the fourth section to distillation and a fifth section being purified dihydroxybenzene; Separation into acetophenone-enriched dihydroxybenzene sixth section Oil-water separation process: Third obtained in the distillation process Separating oil into water and separating it into a seventh section containing ketones and an eighth section containing water. Second extraction process: adding water to the sixth section obtained in the distillation process and adding dihydroxybenzene aqueous solution B Then, the extraction solvent (II) containing aromatic hydrocarbons and the seventh section obtained in the oil-water separation step and / or the ninth section containing dihydroxybenzene and water are subjected to extraction by contact with ketones, and Step for separating into 10th section containing hydroxyacetophenone, aromatic hydrocarbons and ketones Recovery process: 9th stage obtained by recovering dihydroxybenzene from 9th section obtained in 2nd extraction process or 9th stage obtained in 2nd extraction process Supplying the classification to the entrance of the first extraction process

C _A > C _B (1)
(Wherein the C _A, represents the concentration [wt%] of dihydroxybenzene in the dihydroxybenzene aqueous solution A, C _B represents the concentration of dihydroxybenzene in the dihydroxybenzene aqueous solution B [wt%].)

Moreover, this invention is a manufacturing method of dihydroxybenzene including the following process, Comprising: The following purification process concerns on the manufacturing method of dihydroxybenzene using said purification method of dihydroxybenzene.
Oxidation step: Step of oxidizing diisopropylbenzene to obtain an oxidized oil containing diisopropylbenzene dihydroperoxide Decomposition step: Decomposing the oxidized oil obtained in the oxidation step in the presence of an acidic catalyst to obtain a decomposition reaction solution containing dihydroxybenzene Process Purification process: The process of purifying the decomposition reaction solution obtained in the decomposition process to obtain purified dihydroxybenzene

  According to the present invention, hydroxyacetophenone contained in dihydroxybenzene can be efficiently removed.

It is a figure which shows the distribution ratio of the methyl isobutyl ketone to a toluene phase and an aqueous phase. 2 is a schematic diagram of a flow of Example 1. FIG. 6 is a schematic diagram of a flow of Comparative Example 1. FIG. 6 is a schematic diagram of a flow of Example 2. FIG.

  Hereinafter, embodiments of the present invention will be described in detail.

The dihydroxybenzene purification method of the present invention is a dihydroxybenzene purification method for obtaining purified dihydroxybenzene from crude dihydroxybenzene containing isopropenylphenol and hydroxyacetophenone as impurities, the following first extraction step, the following distillation step The dihydroxybenzene concentration in the dihydroxybenzene aqueous solution in the following first extraction step and the following second extraction step includes the following formula (1), including the following oil / water separation step, the following second extraction step and the following recovery step. .
First extraction step: After adding water to the crude dihydroxybenzene to obtain a dihydroxybenzene aqueous solution A, it is brought into contact with an extraction solvent (I) containing aromatic hydrocarbons and ketones and subjected to extraction to obtain dihydroxybenzene, hydroxy Separating into a first section containing acetophenone, ketones and water, and a second section containing isopropenylphenol and aromatic hydrocarbons Distillation process: The first section obtained in the first extraction process is subjected to distillation, Separating into a third section containing water and ketones and a fourth section containing dihydroxybenzene and hydroxyacetophenone, then subjecting the fourth section to distillation and a fifth section being purified dihydroxybenzene; Separation into acetophenone-enriched dihydroxybenzene sixth section Oil-water separation process: Third obtained in the distillation process Separating oil into water and separating it into a seventh section containing ketones and an eighth section containing water. Second extraction process: adding water to the sixth section obtained in the distillation process and adding dihydroxybenzene aqueous solution B Then, the extraction solvent (II) containing aromatic hydrocarbons and the seventh section obtained in the oil-water separation step and / or the ninth section containing dihydroxybenzene and water are subjected to extraction by contact with ketones, and Step for separating into 10th section containing hydroxyacetophenone, aromatic hydrocarbons and ketones Recovery process: 9th stage obtained by recovering dihydroxybenzene from 9th section obtained in 2nd extraction process or 9th stage obtained in 2nd extraction process Supplying the classification to the entrance of the first extraction process

C _A > C _B (1)
(Wherein the C _A, represents the concentration [wt%] of dihydroxybenzene in the dihydroxybenzene aqueous solution A, C _B represents the concentration of dihydroxybenzene in the dihydroxybenzene aqueous solution B [wt%].)

  The crude dihydroxybenzene in the present invention contains at least isopropenylphenol and hydroxyacetophenone as impurities. As impurities, impurities other than isopropenylphenol and hydroxyacetophenone may be contained.

  The concentration of isopropenylphenol in the crude dihydroxybenzene is preferably 0.1 to 20% by weight, and the concentration of hydroxyacetophenone is preferably 0.1 to 10% by weight.

  As a method for obtaining crude dihydroxybenzene in the present invention, for example, benzene and propylene are reacted to form diisopropylbenzene, the diisopropylbenzene is oxidized to diisopropylbenzene hydroperoxide, and the diisopropylbenzene hydroperoxide is acid-decomposed. And dihydroxybenzene and acetone (for example, see JP-A-53-23939).

  Examples of dihydroxybenzene include resorcin, hydroquinone, catechol and the like, and resorcin is preferable from the viewpoint of industrial importance. Resorcin is mainly used as the main raw material for adhesives.

  In the first extraction step of the present invention, water is added to the crude dihydroxybenzene to obtain a dihydroxybenzene aqueous solution A, which is then brought into contact with an extraction solvent (I) containing aromatic hydrocarbons and ketones, and subjected to extraction. This is a step of separating into a first section containing dihydroxybenzene, hydroxyacetophenone, ketones and water and a second section containing isopropenylphenol and aromatic hydrocarbon. Although some of the ketones may be contained in the second section, most of the ketones contained in the extraction solvent (I), for example, 50% or more are distributed to the first section.

The concentration (C _A ) of dihydroxybenzene in the aqueous solution A obtained by adding water to the crude dihydroxybenzene is preferably 40 to 70% by weight, and more preferably 40 to 60% by weight. When the concentration is too low (ie, when the ratio of water to dihydroxybenzene is high), it is separated into a third section containing water and ketones and a fourth section containing dihydroxybenzene and hydroxyacetophenone in the subsequent distillation step. If the concentration is too high (ie, the ratio of water to dihydroxybenzene is low) In addition, the ability to remove isopropenylphenol and hydroxyacetophenone in the extraction process is reduced, causing purification efficiency to deteriorate, and when the solution temperature is lowered, for example, causing precipitation of dihydroxybenzene in the solution when the outside temperature is lowered, It may cause troubles such as blockage of piping.

  The extraction solvent (I) contains aromatic hydrocarbons and ketones, and may contain other solvents. As the aromatic hydrocarbon, for example, toluene, xylene, cymene, triisopropylbenzene, diisopropylbenzene and the like can be mentioned. From the viewpoint of extraction efficiency and liquid separation, toluene is preferable, and ketones are preferable. Ketones having a boiling point lower than that of dihydroxybenzene, more preferably acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like, and more preferably methyl isobutyl ketone.

  Specific methods of extraction include a method of extraction using a known extraction tower. For example, a solution comprising crude dihydroxybenzene and water is supplied from the vicinity of the top of the extraction tower, and the extraction solvent is supplied from the vicinity of the bottom of the tower. Examples include a method of supplying (I) and extracting both by countercurrent contact in an extraction tower. The extraction tower only needs to have a predetermined extraction theoretical stage. For example, a perforated plate extraction tower having a perforated plate installed therein, a baffle tower having a baffle plate installed therein, an RDC tower having a rotating disk attached thereto, and the like. Can be mentioned.

  Another extraction method is, for example, a mixer-settler system in which a solution comprising crude dihydroxybenzene and water is contact-mixed with an extraction solvent (I) using a contact mixing device (mixer), and then oil-water separation is performed. The method of extracting by using is mentioned. Examples of the contact mixing device (mixer) include commercially available general mixing devices such as a stirrer, a static mixer, and a line mixer. An oil / water separator (settler) can be used for the mixer / settler system after contact mixing, and the oil / water separator (settler) may be anything that can sufficiently separate the oil and water, for example, a general drum And coalescers.

By extraction, a first section containing dihydroxybenzene, hydroxyacetophenone, ketones and water and a second section containing isopropenylphenol and aromatic hydrocarbons are obtained. When the extraction tower is used, the first section is obtained from the vicinity of the bottom of the extraction tower, and the second section is obtained from the vicinity of the top of the extraction tower.
On the other hand, when a mixer settler is used, the first section is obtained from the water phase side of the settler and the second section is obtained from the oil phase side.

The concentration of dihydroxybenzene and hydroxyacetophenone included in the first category is preferably 40 to 70% by weight of dihydroxybenzene and 0.05 to 0.4% by weight of hydroxyacetophenone (provided that The total weight of the first section is 100% by weight.) The concentration of isopropenylphenol contained in the second section is preferably 0.05 to 5.0% by weight (provided that the total weight of the second section is 100% by weight).
Since the second section contains aromatic hydrocarbons, it is used as it is as the extraction solvent (II) in the second extraction step or subjected to distillation to recover the purified extraction solvent, and the first and / or second Although it may be recycled as the extraction solvent (I) and / or the extraction solvent (II) in the second extraction step, it should be used as it is as the extraction solvent (II) in the second extraction step as an efficient method of using the extraction solvent. Is preferred.

  In the distillation step in the present invention, the first section obtained in the first extraction step is subjected to distillation, and separated into a third section containing water and ketones and a fourth section containing dihydroxybenzene and hydroxyacetophenone, The fourth section is subjected to distillation to separate the fifth section, which is purified dihydroxybenzene, and the sixth section, which is dihydroxybenzene enriched with hydroxyacetophenone.

  In order to carry out the distillation step, a known distillation column such as a plate column, an irregular packed column, or a regular packed column is used. The main components of the distillation column are internal structures such as shelves (sieve trays, ripple trays, bubble cap trays, etc.), irregular packings (rahishiring, letching, pole rings, etc.), and regular packings (merapacks, etc.). Exemplifying a distillation column main unit installed in combination of one or more, a reboiler for vaporizing a part of the liquid near the column bottom, and a condenser for condensing distillate vapor near the column top Can do. A plurality of such distillation towers are installed as necessary, and separation is performed by extracting a desired section from the vicinity of the top of the tower, the vicinity of the bottom of the tower, or the vicinity of an intermediate stage between the top of the tower and the bottom of the tower. As a specific example, a third section containing water and ketones is obtained from the vicinity of the top of the previous distillation column, a fourth section containing dihydroxybenzene and hydroxyacetophenone is obtained from the vicinity of the bottom of the tower, and then the fourth section is obtained. Distillation is performed in the latter distillation column, and the fifth section, which is dihydroxybenzene purified from near the top of the distillation tower, is obtained, and the sixth section, which is dihydroxybenzene enriched with hydroxyacetophenone, is obtained from near the bottom of the tower. It is done. In the case where impurities having a boiling point lower than that of dihydroxybenzene are present in the dihydroxybenzene obtained in the vicinity of the top of the latter distillation column, a stage located between the stage for supplying the fourth section to the distillation tower and the vicinity of the top of the tower. It is particularly preferable to obtain the fifth section from (side cut stage) from the viewpoint of increasing the purity of the purified dihydroxybenzene.

  The fifth section thus obtained satisfies the desired quality. The concentration of hydroxyacetophenone in the sixth section is usually about 5 to 12% by weight, and dihydroxybenzene is usually about 70 to 95% by weight.

  The oil-water separation step in the present invention is a step of separating the third section obtained in the distillation process into a seventh section containing ketones and an eighth section containing water.

In order to carry out the oil-water separation step, a separation operation such as a distillation operation using a difference in boiling points between water and ketones or a liquid-liquid separation operation using a difference in specific gravity may be used.
When a distillation operation is used, a known distillation column such as a plate column, an irregular packed column, or a regular packed column is used. The main components of the distillation column are internal structures such as shelves (sieve trays, ripple trays, bubble cap trays, etc.), irregular packings (rahishiring, letching, pole rings, etc.), and regular packings (merapacks, etc.). Exemplifying a distillation column main unit installed in combination of one or more, a reboiler for vaporizing a part of the liquid near the column bottom, and a condenser for condensing distillate vapor near the column top Can do.
In addition, as the liquid-liquid separation operation, for example, an oil / water separator (settler) can be used, and as the oil / water separator (settler), any oil / water separator can be used as long as it is allowed to stand and separate. A drum, a coalescer, etc. are mentioned.
The eighth section obtained in the oil / water separation step may be drained out of the process, but from the viewpoint of efficient use of water, the first extraction step and / or the second extraction is performed as is or after removing unnecessary components. It is preferable to recycle as at least a part of the water used in the process, and it is particularly desirable to recycle the whole amount of water used in the second extraction process. By doing so, the amount of waste water as a whole purification process of crude dihydroxybenzene is reduced.

  The second extraction step in the present invention was obtained by adding water to the sixth section obtained in the distillation step to obtain a dihydroxybenzene aqueous solution B, and then in the extraction solvent (II) containing aromatic hydrocarbons and the oil-water separation step. It is a process of subjecting to extraction in contact with the seventh section and / or ketones, and separating into a ninth section containing dihydroxybenzene and water and a tenth section containing hydroxyacetophenone, aromatic hydrocarbons and ketones. .

In addition to dihydroxybenzene and hydroxyacetophenone, the sixth category may contain heavy compounds such as dihydroxybenzene and isopropenylphenol polymerized. A decomposition process may be performed.
As a method of heavy cutting, a known distillation method can be exemplified.
Examples of the thermal decomposition method include a method in which a thermal decomposition unit using a heat exchanger and a gas-liquid separation unit for recovering a thermal decomposition product are combined.

In the second extraction step, the concentration of dihydroxybenzene (C _B ) in the dihydroxybenzene aqueous solution B obtained by adding water to the sixth section obtained in the distillation step is the hydroxyacetophenone removal capability in the second extraction step. From the viewpoint of improving the purification efficiency, the concentration is lower than the concentration (C _A ) of dihydroxybenzene in the aqueous solution of dihydroxybenzene A obtained by adding water to the crude dihydroxybenzene in the first extraction step. It is necessary to satisfy equation (1).
C _A > C _B (1)
(Wherein the C _A, represents the concentration [wt%] of dihydroxybenzene in the dihydroxybenzene aqueous solution A, C _B represents the concentration of dihydroxybenzene in the dihydroxybenzene aqueous solution B [wt%].)

The concentration (C _B ) of dihydroxybenzene in the dihydroxybenzene aqueous solution B is preferably 5 to 30% by weight, and more preferably 5 to 20% by weight.

The extraction solvent (II) contains aromatic hydrocarbons and may contain other solvents. Examples of the aromatic hydrocarbon include toluene, xylene, cymene, triisopropylbenzene, diisopropylbenzene, and the like. From the viewpoint of extraction efficiency and liquid separation property, toluene is preferable. The aromatic hydrocarbon in the extraction solvent (I) used in the first extraction step and the aromatic hydrocarbon in the extraction solvent (II) used in the second extraction step may be the same or different. In order to increase the extraction efficiency, the extraction solvent (II) is preferably a mixed solvent of aromatic hydrocarbons and ketones. The ketones are preferably ketones having a boiling point lower than that of dihydroxybenzene, more preferably acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like, and more preferably methyl isobutyl ketone.
Further, as already described, the second section separated in the first extraction step may be used as it is as the extraction solvent (II).

  Specific examples of the extraction include extraction using a known extraction tower.For example, a solution comprising dihydroxybenzene and water is supplied from the vicinity of the top of the extraction tower, and the extraction solvent is supplied from the vicinity of the bottom of the tower. Examples include a method of supplying and extracting both by countercurrent contact in an extraction tower. The extraction tower only needs to have a predetermined extraction theoretical stage. For example, a perforated plate extraction tower having a perforated plate installed therein, a baffle tower having a baffle plate installed therein, an RDC tower having a rotating disk attached thereto, and the like. Can be mentioned.

As another extraction method, for example, using a contact mixer (mixer), a solution composed of crude dihydroxybenzene and water and an extraction solvent are contact-mixed, and then extracted using a mixer-settler method for oil-water separation. And the like. Examples of the contact mixing device (mixer) include commercially available general mixing devices such as a stirrer, a static mixer, and a line mixer. A known oil / water separator (settler) can be used for oil / water separation after contact mixing.
The oil / water separator (settler) may be anything that sufficiently separates the oil / water, and examples thereof include general drums and coalescers.

By extraction, a ninth section containing dihydroxybenzene and water and a tenth section containing hydroxyacetophenone, aromatic hydrocarbons and ketones are obtained. When the above extraction tower is used, the ninth section is obtained from the vicinity of the bottom of the extraction tower, and the tenth section is obtained from the vicinity of the top of the extraction tower.
On the other hand, when a mixer settler is used, the ninth section is obtained from the water phase side of the settler and the tenth section is obtained from the oil phase side.

  The concentration of dihydroxybenzene contained in the ninth section is preferably 5 to 30% by weight (provided that the total weight of the ninth section is 100% by weight). The concentration of hydroxyacetophenone contained in the tenth section is preferably 0.1 to 1.0% by weight (provided that the total weight of the tenth section is 100% by weight).

In the present invention, since the tenth section contains hydroxyacetophenone, aromatic hydrocarbons and ketones, a recycling step is further provided, and the tenth section is subjected to distillation to extract solvent containing aromatic hydrocarbons and ketones (III And the extraction solvent (III) may be recycled as the extraction solvent (I) and / or the extraction solvent (II) used in the first extraction step and / or the second extraction step.
In the case where impurities such as isopropenylphenol in the crude dihydroxybenzene are concentrated in the tenth section, it is particularly preferable to perform rectification.

  The recovery process in the present invention is a process of recovering dihydroxybenzene from the ninth section obtained in the second extraction process or supplying the ninth section obtained in the second extraction process to the inlet of the first extraction process. Collecting dihydroxybenzene means purifying and collecting dihydroxybenzene.

Examples of the method for recovering dihydroxybenzene include a method in which the ninth section is subjected to distillation and separated into a section containing water and dihydroxybenzene, and each is recovered. Preferably, the second extraction is performed. The ninth section obtained in the process is subjected to distillation, separated into an eleventh section containing water and a twelfth section containing dihydroxybenzene and hydroxyacetophenone, and then the twelfth section is subjected to distillation. This is a step of recovering dihydroxybenzene.
When recovery is performed using distillation, a known distillation column such as a plate column, an irregular packed column, or an ordered packed column is used for the distillation operation. The main components of the distillation column are internal structures such as shelves (sieve trays, ripple trays, bubble cap trays, etc.), irregular packings (rahishiring, letching, pole rings, etc.), and regular packings (merapacks, etc.). Exemplifying a distillation column main unit installed in combination of one or more, a reboiler for vaporizing a part of the liquid near the column bottom, and a condenser for condensing distillate vapor near the column top Can do.
If the composition of dihydroxybenzene does not satisfy the purity required for dihydroxybenzene, an additional distillation column may be installed for rectification. By doing so, dihydroxybenzene contained in the ninth category can be effectively recovered.

  The eleventh section obtained in the recovery step may be drained out of the process, but at least a part of the water used in the first extraction step and / or the second extraction step as it is or after removing unnecessary components. May be recycled as. Recycling the eleventh section is preferable because the amount of waste water in the entire purification process of crude dihydroxybenzene is reduced.

  Supplying the ninth section obtained in the second extraction process to the inlet of the first extraction process means adding the ninth section obtained in the second extraction process as at least part of the source of water added to the first extraction process. At the same time, dihydroxybenzene contained in the ninth section is returned to the first extraction step.

  Since an independent distillation column for recovery is not required, the step of supplying the ninth section obtained in the second extraction step to the inlet of the first extraction step is preferable as the recovery step from the viewpoint of reducing equipment costs. It is.

  In the recycling process of the present invention, the tenth section obtained in the second extraction process is subjected to distillation to recover the extraction solvent (III) containing aromatic hydrocarbons and ketones. It is a step of recycling as at least a part of the extraction solvent (I) and / or the extraction solvent (II) used in the extraction step and / or the second extraction step.

When providing a recycling process, the second section separated in the first extraction process is used as it is as the extraction solvent (II) in the second extraction process, and then the tenth section separated in the second extraction process is subjected to rectification in the recycling process. Thus, the purified extraction solvent (III) is obtained, and the extraction solvent (III) is recycled as at least a part of the extraction solvent (I) used in the first extraction step. It is particularly preferable from the viewpoint of being able to.
By doing so, impurities consisting of isopropenylphenol, hydroxyacetophenone and their polymers removed from dihydroxybenzene in the first extraction step and the second extraction step, respectively, are extracted solvent (I) and extraction solvent (II In the first extraction step and the second extraction step due to a decrease in the purity of the extractant, and a decrease in extraction efficiency can be suppressed.

  In order to carry out the recycling process of the present invention, a known separation operation may be used, but generally a distillation operation is used. For the distillation operation, a known distillation tower such as a plate tower, an irregular packed tower, or an ordered packed tower is used. The main components of the distillation column are internal structures such as shelves (sieve trays, ripple trays, bubble cap trays, etc.), irregular packings (rahishiring, letching, pole rings, etc.), and regular packings (merapacks, etc.). Exemplifying a distillation column main unit installed in combination of one or more, a reboiler for vaporizing a part of the liquid near the column bottom, and a condenser for condensing distillate vapor near the column top Can do. In this way, the extraction solvent (III) is recovered from the vicinity of the top of the distillation column, and the section where the impurities are concentrated is discharged from the vicinity of the bottom of the distillation column.

The greatest feature of the present invention is that the first extraction step and the second extraction step are used in combination, and the extraction solvent (II) containing aromatic hydrocarbons in the second extraction step and the seventh section obtained in the oil-water separation step and / Or in contact with ketones for extraction.
That is, in the conventional method, when an aqueous solution (aqueous phase) containing hydroxyacetophenone and dihydroxybenzene is brought into contact with an extraction solvent (oil phase) composed of aromatic hydrocarbons and ketones to remove hydroxyacetophenone into the extraction solvent. When the concentration of dihydroxybenzene in the aqueous solution is high, ketones are extracted into the aqueous solution, which significantly reduces the extraction performance.

Therefore, the inventors verified the influence of the difference in the concentration of dihydroxybenzene in the aqueous solution on the distribution of ketones between the aqueous phase and the oil phase described above by a model experiment. Resorcin was used as dihydroxybenzene, toluene was used as aromatic hydrocarbon, methyl isobutyl ketone was used as ketones, and two kinds of aqueous solutions of resorcin, 53 wt% and 15 wt%, were used as aqueous solutions.
53 wt% aqueous solution of resorcinol and 15 wt% aqueous solution of resorcinol are brought into contact with toluene containing a predetermined amount of methylisobutylketone, mixed and then separated into oil and water, and the concentration of methylisobutylketone in the toluene phase (hereinafter referred to as the oil phase) The concentration (wt%) of methyl isobutyl ketone in (wt%) and resorcinol aqueous solution (hereinafter in the aqueous phase) was measured by gas chromatography. The results are shown in FIG. When the concentration of methyl isobutyl ketone contained in the oil phase is in the range of 0 to 20% by weight, the concentration of methyl isobutyl ketone in the oil phase (wt%) (X) and the concentration of methyl isobutyl ketone in the aqueous phase (wt%) ) (Y) is almost proportional, so the methyl isobutyl ketone distribution ratio (Y / X) was determined.
As a result, in a low resorcin concentration region such as a 15 wt% aqueous solution of resorcin, the methyl isobutyl ketone distribution ratio is 0.05, and most of the methyl isobutyl ketone is distributed in the oil phase, while 53 wt% resorcin is used. In a high resorcin concentration region such as an aqueous solution, the methyl isobutyl ketone distribution ratio was 0.5, indicating that methyl isobutyl ketone is more easily distributed in the aqueous phase than in the low region.

On the other hand, when the dihydroxybenzene concentration is low, the extraction of ketones into the aqueous solution is suppressed, but the energy for separating dihydroxybenzene and water in the subsequent distillation step increases, resulting in efficient use of hydroxyacetophenone. It could not be removed well.

As a result of intensive research, the inventors have used aqueous solutions having different dihydroxybenzene concentrations in the first extraction step and the second extraction step, and the seventh extraction and / or ketones in the second extraction step having a low dihydroxybenzene concentration. It was found that these problems can be solved by supplying That is, isopropenylphenol can be removed without lowering the dihydroxybenzene concentration in the aqueous solution of the first extraction step, there is no increase in energy for separating dihydroxybenzene and water in the subsequent distillation step, and In the second extraction step, the transfer of ketones to the aqueous phase is suppressed, and efficient removal of hydroxyacetophenone is not hindered.
Here, the reason why the effect cannot be obtained only by combining the first extraction step and the second extraction step without depending on the present invention will be described. When extraction is performed by contacting the extraction solvent (I) used in the first extraction step with the seventh section and / or ketones obtained in the oil-water separation step, most of the ketones are composed of an aromatic hydrocarbon phase (oil Phase) to a dihydroxybenzene aqueous solution phase (water phase), and therefore, it does not sufficiently pass through the first extraction tower and the second extraction tower, and hydroxyacetophenone cannot be efficiently removed.

In the present invention, when dihydroxybenzene is resorcin, it is preferable from the viewpoint of industrial use. Resorcin is mainly used as the main raw material for adhesives.
In the present invention, when dihydroxybenzene is hydroquinone, it is preferable from the viewpoint of industrial use. Hydroquinone is mainly used as a reducing agent, a polymerization inhibitor, a rubber antioxidant, a chemical raw material, and the like.

The present invention is particularly effective when the isopropenylphenol concentration in the crude dihydroxybenzene is 0.1 to 20% by weight and the hydroxyacetophenone concentration is 0.1 to 10% by weight. In the purification of such crude dihydroxybenzene, if the method of the present invention is not used, problems as described above arise.
In the present invention, when the aromatic hydrocarbon contained in the extraction solvent (I) and the extraction solvent (II) is toluene, it is particularly preferable not only in terms of extraction efficiency and liquid separation but also in terms of availability of the extraction solvent. .

Moreover, this invention is a manufacturing method of dihydroxybenzene containing the following process, Comprising: The following purification process is a manufacturing method of dihydroxybenzene using said purification method of dihydroxybenzene.
Oxidation step: Step of oxidizing diisopropylbenzene to obtain an oxidized oil containing diisopropylbenzene dihydroperoxide Decomposition step: Decomposing the oxidized oil obtained in the oxidation step in the presence of an acidic catalyst to obtain a decomposition reaction solution containing dihydroxybenzene Process Purification process: A process for obtaining the purified dihydroxybenzene by purifying the decomposition reaction liquid obtained in the decomposition process. In addition, the light boiling point contained in the decomposition reaction liquid at any place connecting the above decomposition process and the purification process. It is preferable from the viewpoint of efficient purification that components (for example, acetone) and heavy components (compounds obtained by polymerizing dihydroxybenzene, isopropenylphenol, etc.) are separated in advance by a separation operation such as distillation.

  The present invention will be specifically described with reference to examples.

[Example 1] (see FIG. 2)
It is the refinement | purification flow and outline | summary of the crude dihydroxybenzene which employ | adopted this invention.
(I) Reaction step Benzene and propylene are reacted to form m-diisopropylbenzene, then m-diisopropylbenzene is oxidized to m-diisopropylbenzene hydroperoxide, and m-diisopropylbenzene hydroperoxide is present in the presence of an acidic catalyst. Below, it is acid-decomposed to make a reaction solution containing resorcin and acetone, followed by distillation, removing light boiling compounds such as acetone, and resorcin containing m-isopropenylphenol and m-hydroxyacetophenone (m- Dihydroxybenzene) (hereinafter referred to as “crude resorcinol”) was obtained.
(II) Purification step In the first extraction step, the crude resorcinol (1) obtained in the reaction step (I) is obtained in the ninth division (16) obtained in the second extraction step, and additional water (2) as necessary. To give a 53 wt% aqueous solution of resorcin A (3), which is supplied near the top of the extraction column (101), and the extraction solvent (I) (4) containing toluene and methyl isobutyl ketone is added to the weight of the aqueous solution A. The first section containing resorcin, m-hydroxyacetophenone, methyl isobutyl ketone and water is supplied to and brought into contact with the vicinity of the bottom of the extraction tower (101) in an amount of about 0.5 to 0.8 times and subjected to extraction. 5) and a second section (6) containing m-isopropenylphenol and toluene. At this time, the first section (5) was obtained from the vicinity of the bottom of the extraction tower, and the second section (6) was obtained from the vicinity of the top of the extraction tower. At this time, the methyl isobutyl ketone concentration in the extraction solvent (I) was 8.1% by weight.
In the distillation step, first, the first section (5) obtained in the first extraction step is subjected to pre-stage distillation, and the third section (7) containing water and methyl isobutyl ketone and the fourth section containing resorcin and m-hydroxyacetophenone. Separated into section (8).
For the former distillation, a packed distillation column (102) was used. A third section (7) was obtained near the top of the distillation tower (102), and a fourth section (8) was obtained near the bottom of the tower.
Next, the fourth section (8) was subjected to subsequent distillation and separated into the fifth section (9), which was purified resorcin, and the sixth section (10) of resorcin containing m-hydroxyacetophenone.
For the latter distillation, a packed distillation column (103) was used. A fifth section (9) was obtained from the vicinity of the top of the distillation tower (103), and a sixth section (10) was obtained from near the bottom of the tower. The weight of the fifth section (9) was taken out in the range of 0.7 to 0.95 times the weight of the fourth section (8).
In the oil / water separation step, the third section (7) obtained from the vicinity of the top of the previous distillation is supplied to the oil / water separation drum (105), and the seventh section (11) containing methyl isobutyl ketone and the eighth section containing water. Separated into section (12).
In the second extraction step, water (13) and the eighth section (12) are added to the sixth section (10) to form a 15.0% by weight resorcin solution B (14), and the top of the extraction tower (104). Supply to the vicinity, supply the second section (6) and the seventh section (11) obtained in the oil-water separation step to the vicinity of the bottom of the extraction tower (104), contact with the extraction, and include resorcin and water Separated into a ninth section (16) and a tenth section (17) containing m-hydroxyacetophenone, toluene, and methyl isobutyl ketone. In addition, the methyl isobutyl ketone density | concentration in 10th division (17) was 7.0 weight%. At this time, the ninth section (16) was obtained near the bottom of the extraction tower, and the tenth section (17) was obtained near the top of the extraction tower.
In the recovery process, the ninth section (16) obtained in the second extraction process was used as water used in the first extraction process, and at the same time, dihydroxybenzene contained in the section was recovered in the first extraction process.

[Comparative Example 1] (See FIG. 3)
The same purification flow and outline of crude dihydroxybenzene as in Example 1 except that the seventh section (11) after the oil-water separation process is not recycled to the second extraction process but recycled to the extraction solvent (I) (4). there were. At this time, the methyl isobutyl ketone concentration in the tenth section (17) was 2.1% by weight.

  The concentration (% by weight) of methyl isobutyl ketone in the extraction solvent (I) (4) in Example 1 and Comparative Example 1, the concentration (% by weight) of methyl isobutyl ketone in the tenth section (17), product resorcin (9 Table 1 shows the concentration (weight ppm) of m-hydroxyacetophenone in).

From Table 1, the concentration of methyl isobutyl ketone contained in the extraction solvent (I) supplied to the first extraction step was 8.1% by weight in both Examples and Comparative Examples. The methyl isobutyl ketone contained in the passed tenth section (17) was 7.0% by weight in Example 1 to which the present invention was applied, whereas it was 2 in Comparative Example 1 not based on the present invention. 1% by weight.
As described above, the concentration result of methyl isobutyl ketone in the tenth section (17) in Example 1 shows that the transfer of methyl isobutyl ketone supplied to the second extraction step to the aqueous phase is suppressed. It shows that.
From the above, there is a difference in the removal efficiency of m-hydroxyacetophenone in the second extraction step. In Example 1, the concentration of m-hydroxyacetophenone in the product resorcin (fifth category) is 75 ppm by weight, and Comparative Example 1 In the case of applying the present invention, a product having a low m-hydroxyacetophenone concentration of 20 ppm by weight could be obtained efficiently.

[Example 2] (see FIG. 4)
It is the refinement | purification flow and outline | summary of the same crude dihydroxybenzene as Example 1 except having installed the independent distillation tower as a collection | recovery process.

(1) Crude dihydroxybenzene (crude resorcin)
(2) Water (3) Resorcinol aqueous solution A
(4) Extraction solvent (I)
(5) First division (6) Second division (7) Third division (8) Fourth division (9) Fifth division (10) Sixth division (11) Seventh division (12) Eight division (13 ) Water (14) Resorcinol aqueous solution B
(15) Extraction solvent (II)
(16) Ninth section (17) Tenth section (18) Eleventh section (19) Twelve section (20) Dihydroxybenzene recovered (101) Extraction tower of first extraction step (102) Distillation step First distillation column (103) Second distillation column (104) Second extraction column (105) Oil / water separation drum (106) Oil / water separation drum (106) Recovery step first distillation column (107) A distillation column for the latter stage of the recovery process

Claims (10)

A dihydroxybenzene purification method for obtaining purified dihydroxybenzene from crude dihydroxybenzene containing isopropenylphenol and hydroxyacetophenone as impurities, the following first extraction step, the following distillation step, the following oil-water separation step, and the following second extraction A method for purifying dihydroxybenzene, comprising a step and a following recovery step, wherein the dihydroxybenzene concentration in the dihydroxybenzene aqueous solution in the following first extraction step and the following second extraction step satisfies the following formula (1).
First extraction step: After adding water to the crude dihydroxybenzene to obtain a dihydroxybenzene aqueous solution A, it is brought into contact with an extraction solvent (I) containing aromatic hydrocarbons and ketones and subjected to extraction to obtain dihydroxybenzene, hydroxy Separating into a first section containing acetophenone, ketones and water, and a second section containing isopropenylphenol and aromatic hydrocarbons Distillation process: The first section obtained in the first extraction process is subjected to distillation, Separating into a third section containing water and ketones and a fourth section containing dihydroxybenzene and hydroxyacetophenone, then subjecting the fourth section to distillation and a fifth section being purified dihydroxybenzene; Separation into acetophenone-enriched dihydroxybenzene sixth section Oil-water separation process: Third obtained in the distillation process Separating oil into water and separating it into a seventh section containing ketones and an eighth section containing water. Second extraction process: adding water to the sixth section obtained in the distillation process and adding dihydroxybenzene aqueous solution B Then, the extraction solvent (II) containing aromatic hydrocarbons and the seventh section obtained in the oil-water separation step and / or the ninth section containing dihydroxybenzene and water are subjected to extraction by contact with ketones, and Step for separating into 10th section containing hydroxyacetophenone, aromatic hydrocarbons and ketones Recovery process: 9th stage obtained by recovering dihydroxybenzene from 9th section obtained in 2nd extraction process or 9th stage obtained in 2nd extraction process Supplying the classification to the entrance of the first extraction process

C _A > C _B (1)
(Wherein the C _A, represents the concentration [wt%] of dihydroxybenzene in the dihydroxybenzene aqueous solution A, C _B represents the concentration of dihydroxybenzene in the dihydroxybenzene aqueous solution B [wt%].) The method for purifying dihydroxybenzene according to claim 1, further comprising the following recycling step.
Recycling step: The tenth section obtained in the second extraction step is subjected to distillation to recover the extraction solvent (III) containing aromatic hydrocarbons and ketones, and the extraction solvent (III) is recovered in the first extraction step and / or Or a step of recycling as at least a part of the extraction solvent (I) and / or the extraction solvent (II) used in the second extraction step The concentration (C _A ) of dihydroxybenzene in the dihydroxybenzene aqueous solution A is 40 to 70% by weight, and the concentration (C _B ) of dihydroxybenzene in the dihydroxybenzene aqueous solution B is 5 to 30% by weight. The purification method according to 1. The purification method according to claim 1, wherein the recovery step is a step described below.
Recovery process: The ninth section obtained in the second extraction process is subjected to distillation and separated into the eleventh section containing water and the fourteenth section containing dihydroxybenzene and hydroxyacetophenone, and then the twelfth section. Of dihydroxybenzene to recover dihydroxybenzene   The purification method according to claim 1, wherein the dihydroxybenzene is resorcin.   Dihydroxybenzene is hydroquinone, The purification method in any one of Claims 1-4.   The purification method according to any one of claims 1 to 6, wherein the concentration of isopropenylphenol in the crude dihydroxybenzene is 0.1 to 20% by weight and the concentration of hydroxyacetophenone is 0.1 to 10% by weight.   The purification method according to any one of claims 1 to 7, wherein the aromatic hydrocarbon contained in the extraction solvent (I) and the extraction solvent (II) is toluene.   The purification method according to any one of claims 1 to 8, wherein the ketones contained in the extraction solvent (I) are methyl isobutyl ketone. A method for producing dihydroxybenzene, comprising the following steps, wherein the following purification step uses the method for purifying dihydroxybenzene according to any one of claims 1 to 9.
Oxidation step: Step of oxidizing diisopropylbenzene to obtain an oxidized oil containing diisopropylbenzene dihydroperoxide Decomposition step: Decomposing the oxidized oil obtained in the oxidation step in the presence of an acidic catalyst to obtain a decomposition reaction solution containing dihydroxybenzene Process Purification process: The process of purifying the decomposition reaction solution obtained in the decomposition process to obtain purified dihydroxybenzene

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