JP5014773B2 - Method for producing bisphenols - Google Patents

Description

  The present invention relates to a method for producing bisphenols.

  Bisphenols, especially bisphenol A [2,2-bis (4-hydroxyphenyl) propane], is useful as a raw material for polycarbonate resins and epoxy resins, and in recent years, its demand has greatly increased.

  The production process of bisphenols has been conventionally performed by a method using a homogeneous acid such as hydrogen chloride as a catalyst (hereinafter referred to as the “hydrochloric acid method”). A method using a strongly acidic ion exchange resin as a catalyst and a thiol compound as a co-catalyst (hereinafter also referred to as “IER catalyst method”) has become mainstream (see, for example, Patent Documents 1 and 2).

  The production process of bisphenol A by the IER catalyst method is a process in which phenol and acetone are subjected to a condensation reaction in the presence of an IER catalyst, and the resulting reaction mixture is separated from the reaction mixture with unreacted products and produced water as necessary. Removal, concentration, and cooling to produce a slurry containing phenol-bisphenol A adduct crystals, a solid-liquid separation process for separating the adduct crystals from the slurry, a washing process for washing with phenol, etc., phenol by distillation, etc. And a step of treating a part of the mother liquor that has been subjected to solid-liquid separation with a strongly acidic ion exchange resin or the like and then circulating it to the crystallization step.

However, in this IER catalyst method, since the amount of by-products generated is larger than that of the conventional hydrochloric acid method, a product is obtained by performing crystallization and solid-liquid separation operations twice or more (for example, patents). Reference 3). Therefore, it is required to establish a more efficient manufacturing process.
JP 2004-10666 A Japanese Patent Laid-Open No. 10-218814 JP 2003-286214 A

  An object of the present invention is to provide a method for producing high-quality bisphenols efficiently and at low cost by performing the operations of crystallization and solid-liquid separation once.

  The present inventors diligently studied to solve the above problems. As a result, it has been found that the above-mentioned problems can be solved by treating the mother liquor after solid-liquid separation in the main process without recycling it in the sub-process. Moreover, it discovered that a more remarkable effect was acquired by using a specific catalyst. The present inventors have completed the present invention based on these findings.

That is, the method for producing bisphenols according to the present invention includes:
(1) a step of reacting phenol and ketones or aldehydes in the presence of a strong acidic ion exchange resin catalyst, (2) from the reaction solution, water and unreacted ketones or unreacted aldehydes and at least a part of them. Removing phenol and obtaining a first concentrated liquid; (3) cooling the first concentrated liquid to obtain a first crystallization liquid containing adduct crystals of bisphenols and phenol; and (4) first crystal. A main step composed of a step of separating the depositing liquid into an adduct crystal and a mother liquor, and (5) a step of removing phenol from the adduct crystal to obtain a bisphenol.
(6) Step of removing at least a part of phenol from the mother liquor separated from the first crystallization liquid to obtain a second concentrated liquid, (7) Adduct of bisphenols and phenol by cooling the second concentrated liquid A step of obtaining a second crystallization solution containing crystals, (8) a step of separating the second crystallization solution into an adduct crystal and a mother liquor, and (9) the adduct crystal obtained in the step (8) (2) or a sub-process including a process of supplying to the process (3).

  In the method for producing bisphenols of the present invention, at least a part of the mother liquor obtained in the step (8) is treated with a strongly acidic ion exchange resin, and then supplied to the step (6) or the step (7). It is preferable to further include a step (10).

The method for producing bisphenols of the present invention preferably further includes a step (11) of concentrating at least a part of the mother liquor obtained in the step (8) to remove phenol.
The method for producing bisphenols of the present invention is produced by decomposing bisphenols and by-products in the concentrate by heat-treating the concentrate after removal of phenol obtained in the step (11) in the presence of an alkaline catalyst. It is preferable to further include a step (12) of recovering the obtained phenol and 4-isopropenylphenol by distillation.

  In the method for producing bisphenols of the present invention, the phenol is brought into contact with an ion exchange resin and then subjected to a distillation treatment. The distillate is a part of the phenol in the step (1) and the crystal washing liquid in the step (4). It is preferable that the method further includes a step (13) of feeding the bottoms to the step (11) using a part or a part of the crystal cleaning liquid in the step (8).

  The strongly acidic ion exchange resin catalyst used in the step (1) is preferably partially neutralized with a sulfur compound containing a nitrogen atom or a phosphorus atom. The sulfur compound is preferably at least one compound selected from the group consisting of compounds represented by the following formulas (a), (b) and (c).

In formula (a), R _{1 to} R ₃ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, n represents an integer of 1 to 10, and A represents a nitrogen or phosphorus atom. Indicates.

In formula (b), R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, n represents an integer of 1 to 10, and A represents a nitrogen or phosphorus atom Indicates.

In formula (c), m represents an integer of 1 to 20.
In the method for producing bisphenols of the present invention, in the step (1), at least two reactors are connected in series, a heat removal mechanism is provided between the reactors, and the maximum temperature of each reactor is 75 ° C. or lower. It is preferable to suppress the generation of undesirable impurities by suppressing the flow rate of the reaction liquid with respect to the total catalyst weight to 1.2 h ⁻¹ or more.

  In the method for producing bisphenols of the present invention, a part of the first concentrated liquid obtained in the step (2) may be supplied to the step (6) or (7).

  According to the present invention, when producing bisphenols by the IER catalyst method, the operations of crystallization and solid-liquid separation, which have been conventionally performed twice or more, can be reduced to one time, and high-quality bisphenols are produced. Can be efficiently manufactured at low cost.

Hereinafter, the method for producing bisphenols according to the present invention will be described in detail.
As shown in FIG. 1, the method for producing bisphenols of the present invention includes a main process and a sub-process. In the main process, phenol and ketones or aldehydes are reacted to separate bisphenols from the reaction product. In the sub-process, the mother liquor that has been purified and separated in the main process is processed. Hereinafter, each process which comprises a main process and a sub process is demonstrated.

[Main process]
<Step (1)>
In step (1) constituting the main step in the method for producing bisphenols of the present invention, phenol and ketones or aldehydes are reacted in the presence of a strong acidic ion exchange resin catalyst.

  The strong acid ion exchange resin catalyst is not particularly limited, and is, for example, a known strong acid type such as a type in which a sulfone group is introduced into a styrene-divinylbenzene copolymer or a perfluoroalkylsulfonic acid type such as Nafion. An ion exchange resin can be used. The strongly acidic ion exchange resin may be used alone or in combination of two or more.

  The strongly acidic ion exchange resin is preferably partially neutralized with a sulfur compound containing a nitrogen atom or a phosphorus atom. Examples of such a sulfur compound include compounds represented by the following formulas (a), (b) and (c).

In formula (a), R _{1 to} R ₃ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, n represents an integer of 1 to 10, and A represents a nitrogen or phosphorus atom. Indicates.

In formula (b), R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, n represents an integer of 1 to 10, and A represents a nitrogen or phosphorus atom Indicates.

In formula (c), m represents an integer of 1 to 20.
The said sulfur compound may be used individually by 1 type, or may be used in combination of 2 or more type. In the above, the sulfur compound represented by Formula (a) is preferable. Since the strongly acidic ion exchange resin partially neutralized with the specific sulfur compound has high selectivity, the amount of impurities generated can be reduced. Therefore, the purification process of crystallization and solid-liquid separation in the main process can be performed once.

  The method for partially neutralizing the strongly acidic ion exchange resin with the sulfur compound is not particularly limited, and a known method can be employed. For example, a partially neutralized strongly acidic ion exchange resin is obtained by reacting a strongly acidic ion exchange resin and a sulfur compound in a suitable solvent so as to have a predetermined neutralization amount (modification rate). be able to.

  Although it does not specifically limit as the neutralization amount by the said sulfur compound, For example, in the case of a sulfonic acid type ion exchange resin, 0.1 to 50% of all sulfonic acid groups, Preferably it is 3 to 40%, More preferably, it is 5 to 5%. 30%.

  The use ratio of phenol and ketones or aldehydes in the reaction of step (1) is not particularly limited, but for example, 0.1 to 100, preferably “phenol” / “ketones or aldehydes” (molar ratio) Is in the range of 0.5-50, more preferably 3-30.

  The amount of the strongly acidic ion exchange resin catalyst used in the above reaction is not particularly limited. For example, when the reaction is carried out in a batch system, it is preferably 0.001 to 100 parts by weight of phenol as a raw material. The range is 200 parts by weight, more preferably 0.1 to 50 parts by weight.

Although reaction temperature is not specifically limited, Usually, it is 0-200 degreeC, Preferably it is 30-150 degreeC, More preferably, it is the range of 40-90 degreeC. If the reaction temperature is too low, the reaction rate decreases, and if the reaction temperature is too high, undesirable side reactions and the like may proceed, resulting in an increase in by-products and a decrease in reaction selectivity.

  The above reaction can be carried out in any of batch, semi-batch and continuous flow methods. Although it can implement in any form of a liquid phase, a gaseous phase, and a gas-liquid mixed phase, it is preferable to carry out by a liquid phase reaction from a viewpoint of reaction efficiency. Various methods such as fixed bed, fluidized bed, suspension bed, and shelf fixed bed can be used as the catalyst packing method. However, in terms of reaction efficiency, a fixed bed reactor is used. It is desirable to do.

As a preferred embodiment of the step (1), as shown in FIG. 2, at least two reactors 1 are connected in series, and a heat removal mechanism 2 is provided between the reactors so that the maximum temperature of each reactor 1 is 75. A method of suppressing the generation of undesirable impurities by controlling the flow rate (LHSV) of the reaction solution with respect to the total catalyst weight to 1.2 h ⁻¹ or more while suppressing the temperature to below ℃. Thereby, the amount of impurities produced is reduced, and the amount of treatment per unit weight of the catalyst can be increased. The reaction solution obtained in step (1) is supplied to step (2) described later.

<Step (2)>
In the step (2) constituting the main step, water, unreacted ketones or unreacted aldehydes, and at least a part of phenol are removed from the reaction solution obtained in the step (1) for the first concentration. Obtain a liquid.

  The generated water and unreacted substances contained in the reaction solution can be removed by distillation, and the removed unreacted substances can be recovered and recycled to the reaction system again. As distillation conditions, the temperature is usually 100 to 200 ° C. and the pressure is 5 to 80 kPa.

  The remaining concentrated fraction (first concentrated liquid) from which the produced water and unreacted substances have been removed as described above is used as a crystallization raw material in the step (3) described later. In addition, you may supply a part of 1st concentrate obtained at the process (2) to the process (6) or the process (7) mentioned later.

<Step (3)>
In the step (3) constituting the main step, the first concentrated liquid obtained in the step (2) is cooled to obtain a first crystallization liquid containing adduct crystals of bisphenols and phenol.

  Crystallization of the adduct crystal may be performed by a method of cooling with latent heat by adding water and evaporating the water, or by a method of cooling by exchanging heat with cooling water. When adding water, it is normally performed under conditions of a temperature of 30 to 80 ° C. and a pressure of 3 to 13 kPa, preferably a temperature of 40 to 70 ° C. and a pressure of 4 to 10 kPa. The amount of water added is usually about 3 to 20% by weight. It is not preferable to add more water than necessary because the solubility of bisphenols increases and the amount of crystals obtained in step (4) decreases. The obtained first crystallization liquid containing the adduct crystal is solid-liquid separated into the adduct crystal and the mother liquor in the step (4) described later.

  The cooling may be performed in one stage to the final temperature, or may be performed in two or more stages. Usually, cooling in multiple stages often yields clean crystals with few impurities, and therefore cooling in multiple stages is preferred when it is desired to improve crystal purity.

<Process (4)>
In the step (4) constituting the main step, the first crystallization liquid obtained in the step (3) is separated into an adduct crystal and a mother liquor.

The method of solid-liquid separation is not particularly limited, and is performed by a known method such as filtration. The recovered adduct crystals are washed with phenol and dephenolized in step (5) described below. The separated mother liquor is supplied to step (6) described later.

  In the present invention, the mother liquor separated in the main process is not recycled to the main process but is processed in the sub-process described later. Thereby, in this invention, the purification process of the crystallization and solid-liquid separation in the main process conventionally performed twice or more can be reduced to 1 time, and bisphenol can be manufactured at lower cost.

<Step (5)>
In the step (5) constituting the main step, the phenol is removed from the adduct crystals recovered in the step (4) to obtain the desired bisphenols.

  The removal of phenol from the adduct crystal is usually performed by a method in which the washed adduct crystal is separated into bisphenols and phenol by distillation under reduced pressure or the like. As conditions for the said vacuum distillation, temperature is the range of 130-200 degreeC normally, and a pressure is the range of 3-20 kPa.

  By removing the residual phenol contained in the bisphenols obtained by the separation treatment substantially completely by a method such as steam stripping, high-quality bisphenols can be obtained. The removed phenol can be recovered and recycled.

[Sub process]
<Step (6)>
In the step (6) constituting the substep in the method for producing bisphenols of the present invention, at least a part of phenol is removed from the mother liquor separated from the first crystallization liquid in the above step (4), and the second concentration is performed. Obtain a liquid.

  Although the method for removing phenol is not particularly limited, it is usually carried out by distillation. The conditions for distillation are not particularly limited, and for example, the same conditions as in the above step (2) can be employed. The remaining concentrated fraction (second concentrated liquid) from which at least a part of phenol has been removed by distillation is used as a crystallization raw material in the step (7) described later. The removed phenol can be recovered and reused.

<Step (7)>
In the step (7) constituting the substep, the second concentrated liquid obtained in the step (6) is cooled to obtain a second crystallization liquid containing adduct crystals of bisphenols and phenol.

The crystallization method and conditions are the same as in the above step (3). The obtained second crystallization liquid containing the adduct crystal is solid-liquid separated into the adduct crystal and the mother liquor in the step (8) described later.
<Step (8)>
In the step (8) constituting the substep, the second crystallization liquid obtained in the step (7) is separated into an adduct crystal and a mother liquor. Solid-liquid separation can be performed by the same method as in the above step (4). The separated adduct crystals are washed with phenol.

<Step (9)>
In the step (9) constituting the substep, the adduct crystal obtained in the step (8) is supplied to the step (2) or the step (3).

<Step (10)>
In the step (10) constituting the substep, if necessary, at least a part of the mother liquor obtained in the step (8) is treated with a strongly acidic ion exchange resin, and then the step (6) or the step ( 7).

  Thus, after contacting the mother liquor with a strongly acidic ion exchange resin, the isomers of bisphenols are isomerized to the desired bisphenols, and then recycled to the sub-process without being circulated to the main process. It is preferable to do. Thereby, the purification process of the crystallization and solid-liquid separation in a main process can be carried out once. In addition, the strong acid ion exchange resin can use what was mentioned above. Further, the isomerization treatment can be performed by a known method (for example, see JP-A-4-283531 and JP-A-6-321834).

<Step (11)>
In the step (11) constituting the sub-step, if necessary, at least a part of the mother liquor obtained in the step (8) is concentrated to remove phenol.

  The removal of phenol is not particularly limited, but can be performed by distillation in the same manner as in the above steps (1) and (6). The removed phenol can be recovered and recycled. The concentrated liquid after phenol removal is supplied to the process (12) described later.

<Step (12)>
In the step (12) constituting the sub-step, the concentrated solution after phenol removal obtained in the step (11) is heat-treated in the presence of an alkaline catalyst to decompose bisphenols and by-products in the concentrate. The produced phenol and 4-isopropenylphenol are recovered by distillation.

  Examples of the alkaline catalyst include hydroxides, oxides, carbonates, various phenol salts of alkali metals such as sodium and potassium, and hydroxides, oxides, carbonates of alkaline earth metals such as calcium and magnesium. And various phenol salts.

  The method for decomposing bisphenols and by-products in the presence of the alkaline catalyst is not particularly limited, and known methods and conditions can be employed (for example, see JP-A-10-218814).

  4-Isopropenylphenol recovered by distillation can be recovered as bisphenol by condensation with phenol in the presence of an acid catalyst such as an ion exchange resin. This recovery reaction may be performed by providing an independent reactor, or may be performed by supplying the recovered liquid containing 4-isopropenylphenol to Step 10.

[Pretreatment process]
<Step (13)>
In the method for producing bisphenols of the present invention, as a pretreatment step, if necessary, the phenol is brought into contact with an ion exchange resin and then subjected to a distillation treatment, and the distillate is used as a part of the phenol in the step (1), It may further include a step (13) of using the part of the crystal washing liquid in the step (4) or part of the crystal washing liquid in the step (8) and sending the bottoms to the step (11).

  The contact treatment between the phenol and the ion exchange resin can be performed under conditions of a treatment temperature of 50 to 120 ° C. and a contact time of 5 minutes to 10 hours. In addition, as an ion exchange resin, the strong acid ion exchange resin mentioned above can be used.

The distillation after the contact treatment can be performed under conditions of a temperature of 70 to 200 ° C. under a reduced pressure of normal pressure to 10 mmHg. As a result, the amount of impurities produced can be reduced, and higher quality bisphenols can be obtained.

  In addition, it does not specifically limit as phenol made to contact-process, Commercially available phenol and the phenol removed and collect | recovered in the said process can be used.

It is a flowchart which shows the one aspect | mode of the manufacturing method of this invention. It is a schematic diagram which shows one aspect | mode of the process (1) in the manufacturing method of this invention.

Explanation of symbols

1 ... Reactor 2 ... Heat removal mechanism

Claims (8)

(1) a step of reacting phenol with ketones or aldehydes in the presence of a strong acidic ion exchange resin catalyst,
(2) a step of removing water and unreacted ketones or unreacted aldehydes and at least a part of phenol from the reaction solution to obtain a first concentrated solution;
(3) a step of cooling the first concentrated liquid to obtain a first crystallization liquid containing adduct crystals of bisphenols and phenol;
(4) a main step composed of a step of separating the first crystallization liquid into an adduct crystal and a mother liquor, and (5) a step of removing phenol from the adduct crystal to obtain bisphenols,
(6) A step of removing at least a part of phenol from the mother liquor separated from the first crystallization liquid to obtain a second concentrated liquid;
(7) A step of cooling the second concentrated liquid to obtain a second crystallization liquid containing adduct crystals of bisphenols and phenol,
(8) a step of separating the second crystallization liquid into an adduct crystal and a mother liquor ,
(9) supplying the adduct crystal obtained in the step (8) to the step (2) or the step (3) ; and
(10) At least a part of the mother liquor obtained in the step (8) is treated with a strongly acidic ion exchange resin, and then supplied to the step (6) or the step (7) without being circulated to the main step. look including a configured sub-steps in step <br/>, the mother liquor separated in the main process does not recycle to the main process, the manufacturing method of bisphenols, wherein the treatment with sub-step. The method for producing bisphenols according to claim 1, further comprising a step (11) of concentrating at least a part of the mother liquor obtained in the step (8) to remove phenol. The concentrated liquid after phenol removal obtained in the step (11) is heated in the presence of an alkaline catalyst to decompose bisphenols and by-products in the concentrated liquid, and the produced phenol and 4-isopropenylphenol are distilled. The method for producing bisphenols according to claim 2 , further comprising a step (12) of collecting the bisphenol according to claim 2 . After the phenol is brought into contact with the ion exchange resin, a distillation treatment is performed, and the distillate is a part of the phenol in the step (1), a part of the crystal washing liquid in the step (4) or the crystal washing liquid in the step (8). The method for producing bisphenols according to claim 2 , further comprising a step (13) of using as a part of the liquid and sending the bottoms to the step (11). Wherein a strongly acidic ion exchange resin catalyst used is any of claims 1-4, characterized in that it is partially neutralized with a sulfur compound containing a nitrogen atom or phosphorus atom in the step (1) Of producing bisphenols. 6. The bisphenol according to claim 5 , wherein the sulfur compound is at least one compound selected from the group consisting of compounds represented by the following formulas (a), (b) and (c). Production method.

Wherein (a), R ₁ ~R ₃ each independently represent a hydrogen atom, an alkyl group or an aryl group having 1 to 10 carbon atoms, n represents an integer of 1 to 10, A is nitrogen or phosphorus Indicates an atom. ]

[In formula (b), R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, n represents an integer of 1 to 10, and A represents nitrogen or phosphorus. Indicates an atom. ]

[In formula (c), m shows the integer of 1-20. ] In the step (1), at least two reactors are connected in series, and a heat removal mechanism is provided between the reactors to keep the maximum temperature of each reactor to 75 ° C. or lower, and the reaction liquid with respect to the total catalyst weight is reduced. The method for producing bisphenols according to any one of claims 1 to 6 , wherein generation of undesirable impurities is suppressed by setting the weight flow rate to 1.2 h ^-1 or more. A part of the first concentrated liquid obtained in the step (2) is supplied to the step (6) or (7), The production of bisphenols according to any one of claims 1 to 7 Method.

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