TWI593665B - Method for producing bisphenol A. - Google Patents

Description

Method for producing bisphenol A

The present invention relates to a process for producing bisphenol A, and more particularly to a process for producing bisphenol A from phenol and acetone.

Bisphenol A is known as an important compound for engineering plastics such as polycarbonate resins or polyarylate resins, or as raw materials for epoxy resins. In recent years, it has become more and more desirable. Colorless and high purity bisphenol A is required as a raw material for the manufacture of high quality resins.

Bisphenol A can generally be produced by reacting phenol with acetone in the presence of an acidic catalyst. As the acidic catalyst, a strongly acidic cation exchange resin partially modified with a thiamine-containing compound is known. Here, when a sulfur- or nitrogen-containing impurity is eluted from a strongly acidic cation exchange resin partially modified with a thiamine-containing compound, the quality of the produced bisphenol A is deteriorated, and the above-mentioned strongly acidic cation is known. The exchange resin is washed with phenol and then started to react (for example, refer to Patent Document 1). Patent Document 1 describes a method of recovering a recyclable phenol having a low nitrogen concentration by distilling a phenol solution after washing the strongly acidic cation exchange resin.

In addition, phenol has a mutual compatibility with water, The general distillation method has difficulty in separating phenol and water. Therefore, phenol is recovered from a phenol-containing drainage, and it is known to carry out azeotropic distillation using an azeotropic agent represented by ethylbenzene, that is, azeotropic method, or use methyl isobutyl ketone (MIBK). The solvent represented by the solvent is extracted by a solvent extraction method (for example, refer to Patent Documents 2 to 4).

The azeotropic method is a method in which water is separated from phenol by azeotropic distillation by adding an azeotropic agent to a phenol-containing drain. The azeotropy method is an excellent method from the viewpoint of recovering phenol which can be reused after separating water from phenol, but the problem is that in order to recover an azeotropic agent which can be reused after separating the azeotropic agent from water, The energy cost required is too high.

On the other hand, the solvent extraction method is a method of separating phenol from a solvent by separating a phenol from a solvent by adding a solvent to a phenol-containing wastewater, extracting the phenol, and separating the water and the phenol. .

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-315387

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2000-107748

[Patent Document 3] Japanese Patent Laid-Open Publication No. SHO 58-15932

[Patent Document 4] Japanese Patent Publication No. 2007-534471

Strong acidity that is partially modified by the thiamine-containing compound The phenol solution after washing the cation exchange resin contains sulfur or nitrogen-containing impurities such as a free acid or an amine compound. When the phenol containing these impurities is reused in the production of bisphenol A, the quality of the produced bisphenol A may deteriorate.

Patent Document 1 describes that a phenol solution obtained by washing a strongly acidic cation exchange resin partially modified with a thiamine-containing compound is distilled to remove water. However, the problem is that it is difficult to separate phenol and water by a general distillation method, and high energy costs must be invested in order to perform sufficient separation.

Patent Document 2 describes a method of separating water and phenol using an azeotropic agent. However, in order to separate the entrainer from water to recover the recyclable entrainer, there is a problem that the required energy cost is too high.

Patent Document 3 describes that phenol is extracted using methyl isobutyl ketone, water and phenol are separated, and the recovered phenol is recycled to the bisphenol A production step. Further, Patent Document 4 describes a method of separating water and phenol by extracting phenol using a mixture containing methyl isobutyl ketone and anisole. However, in Patent Documents 3 and 4, a strongly acidic cation exchange resin partially modified by a thiamine-containing compound is not disclosed, and it is not assumed that a phenol separated from methyl isobutyl ketone contains a free acid or an amine compound. Contains impurities such as sulfur or nitrogen.

An object of the present invention is to provide a method for producing bisphenol A which is produced by using a strongly acidic cation exchange resin catalyst partially modified with a thiamine compound to produce bisphenol A. The phenol drainage efficiency is good to recover high-purity phenol and reuse it. Efficiently manufacture high quality bisphenol A.

That is, the present invention provides a method for producing bisphenol A according to the following [1] to [10].

[1] A method for producing bisphenol A, which comprises the steps (1) to (4) below, and which comprises the following steps (R1) and (R2), and the phenol obtained in the above step (R2) Further, in at least one of the steps (1) to (4), (1) using a reactor filled with a strongly acidic cation exchange resin catalyst partially modified with a thiamine compound to carry out phenol and acetone a condensation reaction to form bisphenol A, a step of obtaining a reaction mixture containing bisphenol A, and (2) separating a low boiling component from the reaction mixture obtained in the above step (1) to prepare a crystal containing the concentrated bisphenol A Step of analyzing the raw material, (3) crystallization of the crystallization product of bisphenol A and phenol by cooling the crystallization raw material prepared in the above step (2) to form a crystallization product of an adduct of bisphenol A and phenol And the step of separating the crystallization from the reaction mixture, (4) removing the phenol from the crystallization of the bisphenol A and the phenol adduct obtained in the above step (3), and recovering the bisphenol A, R1) using methyl isobutyl ketone to separate water and phenol from the drainage of phenol produced in the production step of bisphenol A, and extracting crude phenol (R2) Distilling the crude phenol extracted in the aforementioned step (R1) Purification to obtain a phenol having a sulfur concentration of 0.5 ppm by mass or less and a nitrogen concentration of 0.1 ppm by mass or less

[2] The method for producing bisphenol A according to [1], further comprising the step (F) of washing the strongly acidic cation exchange resin catalyst with phenol before the step (1), and the step (R1) The phenol-containing drainage system contains the phenol solution washed in the step (F).

[3] The method for producing bisphenol A according to [1] or [2], wherein the step (2) has the following steps (2a) and (2b), and the bottom of the column separated by the step (2a) is used. The liquid (ii) is a step of preparing the crystallization raw material, and the phenol-containing drainage system comprises the top component (i) separated by the step (2a) and/or the bottom liquid (iv) separated by the step (2b).

(2a) using the distillation column to distill the reaction mixture obtained in the above step (1), and separating into a bottom component (i) containing a low boiling component and a bottom liquid (ii) containing bisphenol A and phenol, ( 2b) The overhead component (i) separated in the above step (2a) is further distilled using a distillation column to separate into a top component (iii) containing unreacted acetone and a bottom liquid (iv) containing reaction-generated water. The steps.

[4] The method for producing bisphenol A according to any one of [1] to [3] wherein the thiamine-containing compound is 2-aminoethanethiol or 2,2-dimethylthiazolidine and At least one selected from the group consisting of 4-pyridine ethanethiol.

[5] The method for producing bisphenol A according to any one of [1] to [4], which comprises the step (C) of removing a free acid from a phenol-containing solution by a free acid removal apparatus.

[6] The method for producing bisphenol A according to [5], wherein the free acid removing device is an anion exchange resin.

[7] The method for producing bisphenol A according to [5] or [6], which satisfies at least one of the following (a) to (c).

(a) The reactor used in the above step (1) is provided with an anion exchange resin as a free acid removing device at the outlet.

(b) an isomerization reactor having an isomerization reaction mixture obtained by separating the adduct in the above step (3), the isomerization reactor having a free acid removal at the inlet thereof Anion exchange resin for equipment.

(c) an isomerization reactor having an isomerization reaction mixture obtained by separating the adduct in the above step (3), the isomerization reactor being at the outlet thereof, having as a free acid Remove the anion exchange resin from the equipment.

[8] The method for producing bisphenol A according to any one of [5] to [7], which comprises the step (G) of washing the free acid removal device with phenol, and the step (R1) containing phenol The drainage system contains the phenol solution washed in the step (G), and the phenol obtained in the above step (R2) is reused in the above steps (F), (G), (1), (2), (3). And (4) at least one of the steps selected by the group.

[9] The method for producing bisphenol A according to any one of [5] to [8] wherein the phenol-containing solution is at least selected from the following (i), (ii) and (iii) a phenol-containing solution, (i) a phenol solution washed in the step (F), (ii) a reaction mixture obtained in the step (1), (iii) phenol which is reused in at least one step selected from the group consisting of steps (F), (G), (1), (2), (3) and (4).

[10] The method for producing bisphenol A according to any one of [1] to [9] wherein, before the step (4), the phenol obtained in the step (R2) is used to wash the aforementioned step (3). a crystallization of an adduct of the separated bisphenol A and phenol.

According to the present invention, when bisphenol A is produced by using a strongly acidic cation exchange resin catalyst partially modified with a thiamine-containing compound, high-purity phenol is efficiently recovered from the produced phenol-containing drainage efficiency, and The recovered phenol is reused to efficiently produce high quality bisphenol A.

[Formation of the Invention]

The method for producing bisphenol A according to the present invention comprises the following steps (1) to (4), and comprises the following steps (R1) and (R2), and the phenol obtained in the step (R2) is reused In at least one of the foregoing steps (1) to (4).

(1) using a reactor filled with a strongly acidic cation exchange resin catalyst partially modified with a thiamine-containing compound to carry out a condensation reaction of phenol with acetone to form bisphenol A, and to obtain a reaction mixture containing bisphenol A. The steps.

(2) A step of separating the low-boiling component from the reaction mixture obtained in the above step (1) to prepare a crystallization material containing the concentrated bisphenol A.

(3) The crystallization product of the bisphenol A and the phenol is crystallized by cooling the crystallization raw material prepared in the above step (2) to form a crystallization product of an adduct of bisphenol A and phenol, and is mixed by the reaction. The step of separating the crystallization from the liquid.

(4) A step of removing phenol from the crystallization of the adduct of bisphenol A and phenol obtained in the above step (3), and recovering bisphenol A.

(R1) A step of extracting crude phenol by using methyl isobutyl ketone to separate water and phenol from the drainage of phenol produced in the production step of bisphenol A.

(R2) The crude phenol extracted in the above step (R1) is subjected to distillation and purification to obtain a phenol having a sulfur concentration of 0.5 ppm by mass or less and a nitrogen concentration of 0.1 ppm by mass or less.

<Step (1): Reaction step>

The step (1) is a reaction in which a phenol and acetone are subjected to a condensation reaction to form a bisphenol A by using a reactor filled with a strongly acidic cation exchange resin catalyst partially modified with a thiamine compound, and a reaction containing bisphenol A is obtained. The step of mixing the liquid.

In this step, the supplied phenol and acetone are condensed to form P-isopropenylphenol (IPP), and the IPP and the phenol are further condensed to form bisphenol A.

In the present invention, from the viewpoints of corrosion of the device, separation and recovery of the catalyst after the reaction, and catalytic activity, the catalyst is used. A strongly acidic cation exchange resin partially modified by a thiamine-containing compound.

Examples of the thiamine-containing compound include aminoalkylthiols such as 2-aminoethanethiol, tetrahydrothiazoles such as 2,2-dimethylthiazolidine, and 4-aminothiophenol. A pyridinium thiol such as an aminothiophenol or 4-pyridineethanethiol. Among them, at least one selected from the group consisting of 2-aminoethyl mercaptan, 2,2-dimethylthiazolidine and 4-pyridine ethyl mercaptan is preferred.

In the case of a strongly acidic cation exchange resin, a sulfonic acid type cation exchange resin or the like is preferably used from the viewpoint of catalyst activity. Specific examples of the sulfonic acid type cation exchange resin include a sulfonated styrene-divinylbenzene copolymer, a sulfonated crosslinked styrene polymer, a phenol formaldehyde-sulfonic acid resin, and a benzaldehyde-sulfonic acid resin. These may be used alone or in combination of two or more.

The method of partially modifying the strongly acidic cation exchange resin using a thiamine-containing compound is not particularly limited, and a conventionally known method can be used. For example, the strongly acidic cation exchange resin and the thiamine-containing compound can be modified to react at a desired modification ratio in an aqueous solvent such as a suitable solvent, preferably water. The reaction can be carried out at room temperature, and if necessary, it can be heated. By this reaction, the ion exchange group (sulfonic acid group in the sulfonic acid type cation exchange resin) reacts with the amine group in the sulfur-containing amine compound, and a sulfur-containing group is introduced into a part of the ion exchange group, and is modified. Sex.

Here, the modification ratio of the strongly acidic cation exchange resin means the molar modification ratio due to the thiamine-containing compound having a strongly acidic ion exchange group of a strongly acidic cation exchange resin. In the present invention, the modification ratio of the strongly acidic cation exchange resin caused by the thiamine-containing compound is from the viewpoint of the yield of bisphenol A. Look, it is better to use 5~50%, and 8~35% is better.

From the viewpoint of improving the yield of bisphenol A, the modification ratio of the strongly acidic cation exchange resin caused by the thiamine-containing compound is controlled to an appropriate range, and will be partially modified by the thiamine-containing compound. The strong acid cation exchange resin is preferably washed with phenol before the start of the reaction (step (F)).

The washing is carried out in a continuous or batch manner, and the nitrogen concentration in the washed phenol solution is preferably from 0.01 to 5 ppm by mass. If the nitrogen concentration in the washed phenol solution is too high, the quality of bisphenol A deteriorates. Further, if a large amount of phenol which has a low nitrogen concentration is used, the time required for washing increases, which is economically disadvantageous.

When washing in a continuous manner, the LHSV (liquid space velocity) is usually 0.02 to 10 hr ^-1 , preferably 0.05 to 5 hr ^-1 . When LHSV is in the above range, it can be efficiently washed in a short time without requiring a large amount of phenol. The washing temperature is preferably 45 to 110 ° C, and more preferably 55 to 90 ° C. If the washing temperature is too high, the decomposition of the ion exchange resin progresses, and if the washing temperature is too low, the phenol will solidify.

The condensation reaction of phenol and acetone in the step (1) is carried out using a reactor filled with the above catalyst.

The form of the condensation reaction is not particularly limited, and may be either a batch type or a continuous type. The continuous bed continuous reaction method in which the raw materials are continuously supplied and reacted is preferred, and the fixed bed circulation method in the extrusion flow mode is more preferable. The reaction column in the continuous bed continuous reaction mode may be one column, or may be a fixed bed multi-stage continuous reaction mode in which two towers or more are arranged in series.

In the case of the fixed bed continuous reaction system, the LHSV (liquid space velocity) of the raw material mixture is usually in the range of 0.2 to 30 hr ^-1 , preferably 0.5 to 20 hr ^-1 . The reaction temperature is usually 50 to 100 ° C, preferably 60 to 90 ° C. The phenol/acetone ratio is usually from 3 to 30 (mole ratio), preferably from 5 to 20 (mole ratio).

From the viewpoint of obtaining a high quality adduct crystal which does not substantially contain a free acid, the method of the present invention is preferably a step (step (C)) of removing a free acid from a phenol-containing solution. In step (C), the free acid removal device is used to remove the free acid. For example, the reactor used in the step (1) is preferably one having a free acid removing device at its outlet. Further, it is also preferable that the inlet and/or the outlet of the isomerization reactor used in the isomerization treatment to be described later have a free acid removal device. In the case of the free acid removal device, those described in Japanese Laid-Open Patent Publication No. H1-211-543, No. 2001-316313, and the like. For example, an anion exchange resin such as a weakly basic ion exchange resin or an activated carbon, a basic inorganic acid compound or the like can be used, and an anion exchange resin is more preferably used. The free acid removal apparatus (preferably an anion exchange resin) is preferably one which can be washed by phenol (step (G)).

The step (C) can be carried out by maintaining the free acid concentration in the crystallization raw material supplied in the step (3) at preferably 0.001 to 0.5 meq/L, more preferably 0.001 to 0.10 meq/L. In the present invention, it is preferred to use at least one phenol-containing solution selected from the following (i), (ii) and (iii): (i) after washing in step (F) Phenol solution (supply to step (1) supply raw material liquid), (ii) reaction mixture obtained in the step (1), (iii) in the steps (F), (G), (1), (2), (3) and (4) The phenol which is reused in at least one of the selected groups.

<Step (2): Concentration step>

The step (2) is a step of separating the low-boiling component from the reaction mixture obtained in the above step (1) to prepare a crystallization material containing the concentrated bisphenol A. According to this step, in addition to the removal of low-boiling substances such as unreacted acetone, unreacted phenol, and by-product water from the reaction mixture, the concentration of the produced bisphenol can be adjusted to an appropriate range.

In this step, it is preferred to concentrate the reaction mixture by vacuum distillation using a distillation column.

Further, in the step (2), the following steps (2a) and (2b) are employed, and the bottom liquid (ii) separated in the step (2a) is used to prepare a crystallization material containing the concentrated bisphenol A. The steps are better.

(2a) The reaction mixture obtained in the above step (1) is distilled using a distillation column, and is separated into a bottom component (i) containing a low boiling component and a bottom liquid (ii) containing bisphenol A and phenol.

(2b) The overhead component (i) separated in the above step (2a) is further distilled using a distillation column to separate into a top component (iii) containing unreacted acetone and a bottom liquid containing reaction-generated water (iv ) The steps.

Step (2a), using the distillation column to distill the aforementioned steps (1) The obtained reaction mixture is separated into a bottom component (i) containing a low boiling component and a bottom liquid (ii) containing bisphenol A and phenol.

In the distillation condition in the step (2a), the pressure is preferably from 13 to 70 kPa, more preferably from 20 to 50 kPa, and the temperature is preferably from 30 to 180 ° C, more preferably from 50 to 170 ° C, still more preferably from 60 to 160 ° C. .

In the step (2a), a low-boiling substance containing unreacted acetone, by-product water, and the like, and a part of the top component (i) of phenol can be obtained from the top of the distillation column, and the bisphenol can be obtained from the bottom of the distillation column. A and phenolic bottom liquid (ii).

The overhead component (i) separated in the step (2a) can be further subjected to distillation separation in the step (2b).

In the step (2b), the overhead component (i) separated in the above step (2a) is further distilled using a distillation column to separate into a top component (iii) containing unreacted acetone and a column containing reaction-generated water. The step of the base liquid (iv).

In the distillation condition in the step (2b), the pressure is preferably from 80 to 300 kPa, more preferably from 110 to 200 kPa, and the temperature is preferably from 40 to 150 ° C, more preferably from 50 to 130 ° C.

In the step (2b), the acetone-containing overhead component (iii) can be obtained from the top of the distillation column, and the bottom liquid (iv) containing the reaction-forming water and a part of the phenol can be obtained from the bottom of the distillation column. In the column top component (iii), the recovered acetone system can be reused in the reaction step of the above step (1). On the other hand, since the bottom liquid (iv) contains phenol, water and phenol are separated in the step (R1) described later, and phenol can be recovered.

The bottom liquid (ii) separated in the above step (2a) is subjected to distillation under reduced pressure to distill off excess phenol, whereby the concentration of bisphenol A can be adjusted to a higher concentration. This concentrated liquid is used as a crystallization raw material in the step (3) described later.

In terms of the conditions of the vacuum distillation, the pressure is preferably 4 to 70 kPa, more preferably 10 to 50 kPa, and the temperature is preferably 70 to 170 ° C, more preferably 80 to 140 ° C, and even more preferably 85 to 130 ° C.

The concentration of bisphenol A in the concentrated liquid (crystallizing raw material) thus obtained is preferably from 20 to 60% by mass, more preferably from 20 to 40% by mass. When the concentration is 20% by mass or more, the recovery rate of bisphenol A is sufficient. On the other hand, when it is 60% by mass or less, the curing temperature is increased, and the difficulty in transferring the slurry after crystallization can be prevented.

<Step (3): Crystallization-solid-liquid separation step>

In the step (3), the crystallization product (the adduct) of bisphenol A and phenol is crystallized by cooling the crystallization raw material prepared in the above step (2) to form an adduct of bisphenol A and phenol. The crystallization (adduct crystallisation) and the step of separating the crystallization from the reaction mixture.

The crystallization can be carried out by cooling the crystallization material preferably at 70 to 170 ° C to preferably 35 to 70 ° C, more preferably 40 to 60 ° C. It can also be cooled by using an external heat exchanger, or by vacuum cooling crystallization by the latent heat of evaporation under reduced pressure by adding water to the concentrate.

By crystallization, a crystallized adduct can be obtained. Reaction mixture (mud). The obtained reaction mixture is subjected to solid-liquid separation by filtration, centrifugation or the like to separate the adduct from the reaction mixture. The apparatus used in the separation is not particularly limited, and examples thereof include a belt filter, a barrel filter, a sieve tray filter, and a centrifuge.

Further, the solid component (adduct) after crystallization and solid-liquid separation can be redissolved, and repeated crystallization and solid-liquid separation are repeated. The crystallization and solid-liquid separation are repeated in multiple stages to reduce impurities mixed into the crystal. Examples of the re-dissolved solution include phenol, water, and a water-phenol mixed solution. Further, phenol may be used as the recovered phenol, and an additional supplied phenol may also be used.

The reaction mixture (mother liquor) in which the adduct has been separated in the step (3) contains a 2,4'-isomer of phenol, P-isopropenylphenol, bisphenol A and bisphenol A. Therefore, the reaction mixture can be suitably treated, recycled or reused. For example, isomerization treatment of isomerization of the 2,4'-isomer of bisphenol A to bisphenol A can be carried out. The isomerization treatment can be carried out by means of an isomerization reactor. Further, the reaction mixture and/or the isomerized solution may be subjected to crystallization and solid-liquid separation. Further, an alkali decomposition treatment can be carried out to decompose bisphenol A and an isomer thereof into phenol and P-isopropenylphenol. For the processing of the above, for example, JP-A-2004-315387, JP-A-2004-359594, JP-A-2009-242316, and the like can be referred to.

<Step (4): Adduct decomposition step>

Step (4), which is bisphenol A and phenol obtained from the above step (3) The crystallization of the adduct removes phenol and the step of recovering bisphenol A.

It is preferred to wash the adduct crystals with phenol before the step (4). Further, as the phenol, recovered phenol may be used, and additionally supplied phenol may be used.

In the step (4), the solid content of the adduct is heated and melted at 100 to 160 ° C to obtain a melt which decomposes the adduct into bisphenol A and phenol. Then, the molten liquid is sent to an evaporation tower, and phenol is removed from the melt by vacuum distillation or the like to recover bisphenol A in a molten state. The vacuum distillation is preferably carried out under the conditions of a temperature of usually 150 to 190 ° C and a pressure of usually 1.3 to 13.3 kPa, preferably 1 to 11 kPa. Further, it is preferred that the recovered bisphenol A in the molten state is further removed by steam stripping to remove residual phenol. Through such a step, high purity bisphenol A can be obtained.

The bisphenol A in which the molten state of phenol is removed is a product which can be formed into droplets by a general granulation apparatus and solidified by cooling.

<Step (R1): Extraction step>

In the step (R1), methyl isobutyl ketone is used to separate water and phenol from the wastewater containing phenol produced in the production step of bisphenol A, and a crude phenol is extracted.

In the production method of bisphenol A, generally, phenol is used as a raw material and a cleaning liquid, and a phenol-containing drainage is produced. From the viewpoint of environmental safety, the phenol-containing drainage can be discharged to the outside of the system by separating the phenol, and from the viewpoint of obtaining a high-purity product bisphenol A, the high purity is recovered. The degree of phenol is expected. Here, in the case of using a strongly acidic cation exchange resin catalyst partially modified with a thiamine-containing compound, a sulphur- or nitrogen-containing impurity containing a free acid or an amine compound in the phenol solution, if it is contained The impurity phenol is reused in the production of bisphenol A, and the quality of the produced bisphenol A deteriorates. On the other hand, in the present invention, water and phenol are separated from the phenol-containing drainage using methyl isobutyl ketone, and crude phenol is extracted, and then the crude phenol is distilled and purified to recover high-purity phenol.

Examples of the phenol-containing drainage include a phenol solution washed in the step (F), a phenol solution washed in the step (G), a top component (i) separated in the step (2a), and a step (2b). The separated bottom liquid (iv) also contains phenol-containing drainage discharged from the vacuum generating device.

The phenol-containing drainage, firstly, can be cooled to 20 to 50 ° C, and after mixing with methyl isobutyl ketone, it can be separated into an aqueous phase and an oil phase by standing. Most of the phenol in the drainage can be extracted from the oil phase by methyl isobutyl ketone.

Phenol has a mutual compatibility with water and methyl isobutyl ketone, and also contains a part of phenol in the aqueous phase. Thus, the separated aqueous phase is further sent to a stripping column where it is contacted with methyl isobutyl ketone and the phenol in the aqueous phase can be extracted as methyl isobutyl ketone. Thereby, the phenol concentration in the aqueous phase can be reduced from 3 to 10% by mass to 0.001 to 0.1% by mass, and the drainage can be handled by an existing method.

For the extraction treatment, reference is made to the description of JP-A-58-15932. The extraction tower can be a general porous plate extraction tower, and can also be used for spinning. The round plate extracts the tower or the vibrating plate tower.

<Step (R2): Phenol Recovery Step>

In the step (R2), the crude phenol extracted in the above step (R1) is subjected to distillation and purification to obtain a phenol having a sulfur concentration of 0.5 ppm by mass or less and a nitrogen concentration of 0.1 ppm by mass or less.

The crude phenol extracted in the step (R1) may be further purified by distillation containing sulfur or nitrogen-containing impurities such as a free acid or an amine compound to recover high-purity phenol.

The sulfur concentration in the obtained phenol is 0.5 ppm by mass or less, preferably 0.3 ppm by mass or less, more preferably 0.2 ppm by mass or less. Further, the concentration of nitrogen in the obtained phenol is 0.1 ppm by mass or less. When the sulfur concentration and the nitrogen concentration in the phenol are in the above range, even if the recovered phenol is reused as a reaction raw material or a cleaning liquid, the quality of the produced bisphenol A is not deteriorated.

Further, the water content of the obtained phenol is preferably 300 ppm by mass or less, more preferably 200 ppm by mass or less, still more preferably 100 ppm by mass or less. When the water content of phenol is in the above range, the solubility of bisphenol A to phenol is low, and when it is used for the washing liquid of the adduct crystal, the dissolution loss of the adduct crystal is reduced. Thereby, the amount of bisphenol A/phenol which is circulated in the upstream flow is lowered, which may reduce the amount of business use or reduce the scale of the instrument.

The phenol obtained in the step (R2) can be further purified by ion exchange resin. At this time, an acid type ion exchange resin can be used for the ion exchange resin.

The phenol obtained in the step (R2) is at least one step selected from the group consisting of the steps (F), (G), (1), (2), (3) and (4), and is reused as a reaction raw material. A cleaning solution of a strongly acidic cation exchange resin catalyst or an anion exchange resin, a cleaning solution of an adduct crystal, and the like.

[Examples]

The invention is further illustrated by the following examples, but the invention is not limited to any such embodiments.

Further, in the following examples and comparative examples, phenol, bisphenol A, and the like which were produced in the production steps were quantified by HPLC analysis.

In addition, 20 g of bisphenol A was dissolved in 20 ml of ethanol, and a spectrophotometer (manufactured by Hitachi, Ltd., product name: "U-3410 self-recording spectrophotometer") was used for the color phase (APHA) of the produced bisphenol A. After standing at 260 ° C for 10 minutes in an air atmosphere, the hue was measured by a colorimetric method based on JIS K 4101.

Example 1

In the case of a catalyst, a sulfonic acid type cation exchange resin (manufactured by Mitsubishi Chemical Corporation, product name: "DIAION-SK104H") is filled with 20 mol% of a sulfonic acid group with 2-aminoethyl mercaptan. In a fixed-bed reactor in which a part of the modifier is used as a catalyst, a mixture of 510 kg/h of phenol and 45 kg/h of acetone is initially supplied, while maintaining the temperature of the catalyst layer at 80 ° C, and the liquid space velocity is 1.0 hr ^{- 1} Supply continuously. Then, bisphenol A is produced to obtain a reaction mixture containing the bisphenol A (step (1)).

The obtained reaction mixture was passed through an anion exchange resin (manufactured by Rohm and Haas Co., Ltd., product name: "AMBERLYST A21") (step (C)), and the main fraction was distilled from the reaction mixture under the conditions of a temperature of 150 ° C and a pressure of 40 kPa. The unreacted acetone, the reaction product water, and the low-boiling substance are removed, and then the phenol is mainly distilled off under the conditions of a temperature of 90 ° C and a pressure of 10 kPa, thereby concentrating the reaction mixture to obtain a concentrated bisphenol A-containing crystallization material ( Step (2)).

The concentrate was cooled from 90 ° C to 45 ° C, and the solid content of the adduct (adduct) containing bisphenol A and phenol was crystallized, and then separated by a centrifuge to separate the solid matter into 110 kg/ Mother liquor of h (step (3)).

The solid matter (adduct crystal) is washed, melted, and decomposed by the adduct, and then sent to a distillation column operated at a temperature of 170 ° C and a pressure of 2 kPa, and the phenol is distilled off and recovered. Then, the solution containing bisphenol A was taken out from the bottom of the distillation column, and the residual phenol was completely removed from the solution by steam stripping to obtain 63 kg/h of bisphenol A (step (4)).

First, 23 kg/hr of phenol drainage (30% by mass of phenol) was mixed with methyl isobutyl ketone, and then left to stand to separate into an aqueous phase and a MIBK phase. The separated aqueous phase is brought into contact with methyl isobutyl ketone (MIBK) in a perforated plate extraction column, and the obtained MIBK phase is subjected to distillation treatment in a distillation column to obtain MIBK from the top of the column and crude phenol from the bottom of the column. (Step (R1)). The obtained crude phenol had a sulfur concentration of 0.9 ppm and a nitrogen concentration of 0.2 ppm.

This crude phenol is further subjected to distillation treatment in a distillation column to obtain purified phenol from the top of the column (step (R2)). The sulfur concentration in the obtained purified phenol is 0.1 ppm or less, and the nitrogen concentration is also 0.1 ppm or less. Further, the obtained purified phenol had a water content of 100 ppm by mass.

The obtained purified phenol was reused as a washing liquid of the adduct crystal, and then, as described above, the production of bisphenol A was carried out. The hue (APHA) of the produced bisphenol A was 10.

Example 2

The modified cation exchange resin catalyst used in Example 1 was washed with 4 times the amount of pure water, and then washed with 4 times the amount of phenol (step (F)). As a result, 500 kg of a phenol solution was produced as a washing waste liquid.

After the catalyst was washed, bisphenol A was produced through steps (1) to (4) in the same manner as in Example 1.

The phenol solution was mixed with phenol drainage in Example 1 at 4 kg/hr (75 mass% of phenol), and the same procedure as in Example 1 was carried out to obtain crude phenol, and purified phenol was further obtained. The obtained crude phenol had a sulfur concentration of 1.7 ppm and a nitrogen concentration of 0.4 ppm. Further, the sulfur concentration in the obtained purified phenol was 0.1 ppm or less, the nitrogen concentration was also 0.1 ppm or less, and the obtained purified phenol had a water content of 300 ppm by mass.

Next, in the same manner as in Example 1, the obtained purified phenol was reused as a washing liquid of the adduct crystal, and then, as described above, the production of bisphenol A was carried out. The hue (APHA) of the produced bisphenol A was 10.

Comparative example 1

In the first embodiment, the crude phenol obtained by draining the phenol was not subjected to distillation treatment, but was directly reused as a washing liquid of the adduct crystal, and was produced in the same manner as in Example 1 to produce bisphenol A. The hue (APHA) of the produced bisphenol A was 15.

Comparative example 2

In the second embodiment, the crude phenol obtained by draining the phenol was not subjected to distillation treatment, but was directly reused as a washing liquid of the adduct crystal, and was produced in the same manner as in Example 2 to produce bisphenol A. The hue (APHA) of the produced bisphenol A was 25.

[Industrial Availability]

According to the present invention, high-purity phenol can be efficiently recovered and reused from the drainage of phenol which is produced by using a strongly acidic cation exchange resin catalyst partially modified with a thiamine-containing compound to produce bisphenol A. The recovered phenol efficiently produces high quality bisphenol A. As the obtained bisphenol A, a raw material of an engineering plastic such as a polycarbonate resin or a polyarylate resin can be used.

Claims (9)

A method for producing bisphenol A, which has the following steps (1) to (4) and contains the following steps (R1) and (R2); (1) using a portion filled with a thiamine-containing compound a reactor for modifying a strong acidic cation exchange resin catalyst, a step of condensing phenol with acetone to form bisphenol A, and obtaining a reaction mixture containing bisphenol A, and (2) obtaining the above step (1) The reaction mixture separates the low-boiling components to prepare a crystallization raw material containing the concentrated bisphenol A, and (3) the crystallization of the bisphenol A and the phenol by cooling the crystallization raw material prepared in the above step (2) The crystallization of the product to form a crystallization product of an adduct of bisphenol A and phenol, and the step of separating the crystallization product from the reaction mixture, and (4) the bisphenol A and the phenol obtained from the above step (3) The crystallization of the adduct removes phenol, and the step of recovering bisphenol A, and (R1) uses methyl isobutyl ketone to separate water and phenol from the drainage of phenol produced in the production step of bisphenol A. Step of extracting crude phenol, (R2) purifying and purifying the crude phenol extracted in the above step (R1) to obtain a sulfur concentration of 0.5 ppm by mass or less a step of phenol having a nitrogen concentration of 0.1 ppm by mass or less, wherein the step (1) further comprises the step (F) of washing the strongly acidic cation exchange resin catalyst with phenol, and the step (R1) is contained in the step (1). The phenol drainage system comprises the phenol solution washed in the step (F), and the phenol obtained in the above step (R2) is reused in the foregoing steps. At least one of the steps selected by the group consisting of (F), (1), (2), (3), and (4). The method for producing bisphenol A according to claim 1, wherein the step (2) has the following steps (2a) and (2b), and the bottom liquid (ii) separated in the step (2a) is used to prepare the aforementioned In the step of crystallization of the raw material, the phenol-containing drainage system comprises the top component (i) separated in the step (2a) and/or the bottom liquid (iv) separated in the step (2b); (2a) is distilled using a distillation column The reaction mixture obtained in the above step (1) is separated into a bottom component (i) containing a low boiling component and a bottom liquid (ii) containing bisphenol A and a phenol, and (2b) the aforementioned step (2a) The separated top component (i) is further distilled using a distillation column to separate into a bottom component (iii) containing unreacted acetone and a bottom liquid (iv) containing reaction-generated water. The method for producing bisphenol A according to claim 1, wherein the thiamine-containing compound is selected from the group consisting of 2-aminoethanethiol, 2,2-dimethylthiazolidine and 4-pyridineethanethiol. At least one of them. The method for producing bisphenol A according to claim 1, which comprises the step (C) of removing the free acid from the phenol-containing solution by a free acid removing device. The method for producing bisphenol A according to claim 4, wherein the free acid removing device is an anion exchange resin. The method for producing bisphenol A according to claim 4 or 5, which satisfies at least one of the following (a) to (c), (a) The reactor used in the above step (1) is at the outlet, having an anion exchange resin as a free acid removal device, and (b) having an addition product to be separated in the aforementioned step (3) An isomerization reactor for isomerization of a reaction mixture, the isomerization reactor being at its inlet, having an anion exchange resin as a free acid removal device, (c) having the aforementioned step (3) An isomerization reactor for isomerizing a reaction mixture in which an adduct is separated, the isomerization reactor being at its outlet, having an anion exchange resin as a free acid removal device. The method for producing bisphenol A according to claim 4, which comprises the step (G) of washing the free acid removing device with phenol, and the phenol-containing drainage system in the step (R1) is washed in the step (G). a subsequent phenol solution, and the phenol obtained in the above step (R2) is reused in the group selected from the above steps (F), (G), (1), (2), (3) and (4). At least 1 step. The method for producing bisphenol A according to claim 4, wherein the phenol-containing solution is at least one phenol-containing solution selected from the following (i), (ii) and (iii), (i) step (F) the phenol solution after washing, (ii) the reaction mixture obtained in the step (1), and (iii) in the steps (F), (G), (1), (2), (3) and (4) Phens that are reused in at least one of the selected groups. The method for producing bisphenol A according to claim 1, wherein before the step (4), the phenol obtained in the step (R2) is used to wash the bisphenol A and the phenol separated by the step (3). A crystallization of the adduct.