KR101090193B1 - Process For Production Of Bisphenol A - Google Patents

Abstract

In the method for producing BPA having a step of re-supplying a part of the mother liquor obtained in the production process of bisphenol A (BPA) to the reaction system, deterioration of the activity of the production catalyst of BPA is prevented.

A reaction step of reacting acetone with phenol (PL) to obtain a reaction mixture containing BPA and PL, a low boiling point component separation step for separating the BPA-containing component from the reaction mixture, and a BPA-based material from the BPA-containing component And a BPA separation step of separating PL into a mother liquor having a main component, a hard powder separation step of separating at least a portion of the mother liquor into a hard powder and a heavy powder by heat treatment and distillation in the presence of an alkali, and separating the separated hard powder into a catalyst. A method for producing BPA comprising a recombination reaction step of treating in the presence of light and recombining PL and isopropenylphenol in a hard powder to convert to BPA, wherein the content of isopropenylphenol in the reaction solution is 4% by weight or less in the reaction step. To control.

Bisphenol A, isopropenylphenol

Description

Process For Production Of Bisphenol A

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing bisphenol A, and more particularly, in a method for producing bisphenol A having a step of treating impurities contained in a part of the mother liquor obtained in the separation step of bisphenol A and then resupplying them to the reaction system. The present invention relates to a method for producing bisphenol A, which can prevent active degradation of a production catalyst.

Bisphenol A is usually manufactured using phenol and acetone as raw materials. As a typical manufacturing method, there is a method of reacting the raw material in the presence of an acidic catalyst such as a cation exchange resin, but the reaction mixture obtained in this method is unreacted phenol, unreacted acetone, reaction water and coloring other than bisphenol A as a target product. Reaction by-products such as substances. As a method of separating these reaction by-products from the reaction mixture, distillation is usually employed. In this case, the distillation column is distilled at a temperature lower than the boiling point of phenol, and low boiling point components such as unreacted acetone, reaction product water, and some unreacted phenol are recovered from the column top, and a component containing bisphenol A is obtained from the column bottom. . Then, the component containing bisphenol A from the bottom is separated into a substance containing bisphenol A as a main component and a mother liquid containing phenol and reactive impurities as a main component.

Most of the mother liquor is resupplied to the reaction system, but in order to avoid accumulation of isomers or high boiling point impurities in the reaction system, a part of the mother liquor is usually extracted to remove impurities. As a method for removing impurities, a method of heating an alkali is added to decompose bisphenol A and its isomers into phenol and isopropenylphenol. At this time, some of the other impurities are neutralized and removed out of the system as tar. This decomposition reaction is usually carried out by a reaction distillation method, and the phenol and isopropenyl phenol produced by the decomposition reaction are fed to a recombination reactor containing an acidic ion exchange resin catalyst, thereby producing bisphenol A (for example, Patent Documents 1 to 1). 3). The reaction liquid flowing out of the recombination reactor is resupplied to the reaction system together with the mother liquid which has not removed impurities.

However, even when a part of mother liquor was taken out and an impurity removal process was performed by alkali heat processing, deterioration of the acidic ion exchange resin catalyst of a reaction process arises and it was stable for a long time, and bisphenol A could not be manufactured.

Moreover, as a result of examining the activity deterioration of the catalyst by isopropyl phenol, it was found that methanol contained in the raw material acetone further promotes the activity deterioration by isopropyl phenol. It is known that the raw material acetone contains a trace amount of methanol as an impurity, and the methanol reduces the catalytic activity of the aminothiol-supported ion exchange resin catalyst (for example, Patent Documents 4 and 5). However, there is no known effect of promoting activity degradation with alkylphenols such as isopropylphenol.

Patent Document 1: Japanese Patent Application Publication No. 49-48319

Patent Document 2: Japanese Patent Application Laid-Open No. 1-230538

Patent Document 3: Japanese Patent Laid-Open No. 5-331088

Patent Document 4: Japanese Patent Application Laid-Open No. 6-92889

Patent Document 5: Japanese Patent Application Laid-Open No. 6-25047

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing bisphenol A having a process of impurity treatment of at least a part of the mother liquor obtained in the bisphenol A separation step and resupplying to the reaction system. The present invention provides a method for producing bisphenol A that can suppress deterioration.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, as a result of earnestly examining by the present inventors, the isopropyl phenol byproduced by the heat processing in presence of alkali promotes the active deterioration of the acidic ion exchange resin catalyst of a reaction process. It was found that deterioration of the acidic ion exchange resin catalyst in the reaction step can be suppressed by controlling the amount of isopropylphenol in the reaction solution in a specific range in the reaction step, and the present invention has been completed.

The gist of the present invention is a reaction step of reacting acetone of a raw material component with phenol in the presence of an acidic ion exchange resin catalyst to obtain a reaction mixture containing bisphenol A and phenol, and reacting the reaction mixture with a component containing bisphenol A and unreacted acetone. Low boiling point component separation process to separate into low boiling point component containing a, bisphenol A separation process to separate the component containing bisphenol A into the main stream containing bisphenol A, and mother liquor containing phenol as a main component, separated mother liquid Hard powder separation step of separating at least a portion of the hard powder into a hard powder and a heavy powder by heating and distillation in the presence of an alkali, and the separated hard powder is treated in the presence of an acidic ion exchange resin catalyst to give phenol and isopropenylphenol in the hard powder. Reaction process to recombine and convert to bisphenol A. A method for producing bisphenol A containing a recombination reaction solution circulation process, at least, in the production process of bisphenol A to the content of isopropyl phenol in the reaction solution from the reaction step, characterized in that the control to not more than 4% by weight.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated in detail, description of the element | module described below is a typical example of embodiment of this invention, and this invention is not limited to these content. The method for producing bisphenol A of the present invention is a reaction step of reacting acetone of a raw material component with phenol in the presence of an acidic ion exchange resin catalyst to obtain a reaction mixture containing bisphenol A and phenol, and the reaction mixture is a component containing bisphenol A. Low boiling point component separation process to separate into low boiling point component containing unreacted acetone, bisphenol A separation of bisphenol A-containing components into bisphenol A-based substances and mother liquor containing phenol and reactive by-products as main components Process, separation of hard powders by heating and distillation of at least a part of the separated mother liquor into hard and heavy powders by distillation, and processing the separated hard powders in the presence of an acidic ion exchange resin catalyst Recombination reaction process to recombine and isopropenylphenol and convert to bisphenol A. And a recombination reaction solution circulation step of circulating the condensate to the reaction step. In addition, if necessary, the unreacted acetone is separated and recovered from the low boiling point component obtained in the low boiling point component separation step, the acetone circulation step for circulating in the reaction step, or the mother liquor circulation step for circulating in the reaction step without processing a part of the separated mother liquid. It may include.

First, in order to facilitate understanding of the present invention, an outline of a method for producing bisphenol A will be described based on the flowchart in FIG. 1, but the manufacturing method of the present invention can be various embodiments.

The raw materials acetone and phenol are fed to the reactor 2 via line 1. The reaction mixture from reactor 2 is introduced into distillation column 4 via line 3. The low boiling point component containing acetone, water, phenol and the like extracted from the column top of the distillation column 4 is transferred to the separation system 20 and separated into acetone, water and phenol by distillation or the like. Acetone is conveyed via line 21 and line A to methanol removal apparatus 1a as a purifier described later. Water is discharged out of the system from the separation system 2. The phenol is fed from the separation system 20 to the purifier 20a and purified before being transferred to the phenol storage tank 22.

The bottom component of the distillation column 4 is transferred to the crystallizer 5, and the crystal adduct formed by adding bisphenol A and phenol is precipitated. This crystalline adduct is solid-liquid separated in the solid-liquid separator (6) and then re-dissolved in the redissolver (7), recrystallized in the re-calculator (8), in a solid-liquid separation and rinse system (9) consisting of a centrifuge or the like. Is processed. Here, the rinse (cleaning) of the crystal adduct is performed with clean phenol supplied from the tank 22. The rinse waste liquor is conveyed via line 10 to re-dissolver 7 (or used for rinsing solid-liquid separator 6 via line 17). The crystalline adducts after rinsing are heated in the adduct decomposition device 11 to be decomposed into bisphenol A and phenol, and the bisphenol A is processed in the purifier 12 to be a product bisphenol A. The phenol separated in the adduct cracker 11 and the purifier 12 is transferred to the tank 22.

At least a part of the separation liquid (mother liquor) separated by the solid-liquid separator 6 is supplied to the impurity removal line 13 ', and impurities are removed. In the removal of impurities, at least a part of the mother liquor is concentrated in the mother liquor concentration tower 13c, and then heated in the presence of alkali in the alkali decomposition tower 13a, and then separated into hard and heavy components, and the hard component is a recombination reactor. The recombination reaction treatment is carried out in (13b) and recycled back to line (13). In addition, part of the mother liquor may be transferred to the mother liquor tank 14 via the line 13. The mother liquor in the mother liquor tank 14 is transferred to the line 1 via the line 15, mixed with acetone and supplied to the reactor 2. In addition, the mother liquor in the mother liquid tank 14 is also transferred to the line 3 via the line 16.

In the mixed liquid of acetone and mother liquor supplied to the reactor 2, the supply amount of the mother liquor introduced into the line 1 from the line 15 is controlled so that the ratio of acetone and phenol may become a predetermined range. When the ratio of acetone and phenol falls within a predetermined range, the quality and yield of the product bisphenol A are stable. The mother liquor tank 14 also serves as a buffer tank for leveling the fluctuations in the circulation amount from the line 13.

Hereinafter, each process is demonstrated.

<Reaction Process>

In the reaction carried out in the reactor 2, phenol and acetone of the raw material are reacted in stoichiometric amounts in excess of phenol. The molar ratio (phenol / acetone) of phenol and acetone is usually 3 to 30, preferably 5 to 20. The reaction temperature is usually from 50 to 100 ° C, and the reaction pressure is usually from normal pressure to 600 kPa (absolute pressure).

As acetone of a raw material, if it is industrially available, it can be used without a restriction | limiting in particular. For example, purified acetone newly supplied from outside the system, acetone obtained by treating the unreacted acetone separated in the low boiling point component separation step described later in the acetone circulation step, a mixture thereof and the like can be used.

As the catalyst, a strong acid cation exchange resin such as a sulfonic acid type, preferably a resin in which a strong acid cation exchange resin is partially modified with a sulfur-containing amine compound is used. In particular, when a resin modified with a sulfur-containing amine compound such as 2-aminoethanethiol or 2- (4-pyridyl) ethanethiol is used, the effect of the present invention becomes remarkable. The degree of modification by the sulfur-containing amine compound is usually 2 to 30 mol%, preferably 5 to 20 mol% with respect to the acid group (sulfonic acid group) in the acidic ion exchanger.

The condensation reaction of phenol and acetone is usually carried out in a fixed bed circulation method or a suspended bed ash method. In the case of the fixed bed flow system, the liquid space velocity of the raw material mixture supplied to the reactor is usually 0.2 to 50 / h. In the case of the suspended bed batch system, the amount of acidic ion exchange resin catalyst used is usually 20 to 100% by weight based on the raw material mixture, and the reaction time is usually 0.5 to 5 hours, depending on the reaction temperature and the reaction pressure.

<Low boiling point component separation process>

The reaction mixture obtained in the reaction step is separated into a component containing bisphenol A and a low boiling point component containing unreacted acetone. As the separation method, as described above based on the flowchart of FIG. 1, the distillation column 4 is used, the reaction mixture obtained in the reaction step is distilled off, and the low boiling point component containing unreacted acetone is separated from the column top. The column bottom liquid is a liquid component containing bisphenol A. As a distillation column, a well-known thing can be used. When distillation is performed at normal pressure, it is below the boiling point of a phenol, Preferably it is performed by vacuum distillation. Distillation under reduced pressure is normally performed at a temperature of 50-150 degreeC and a pressure of 50-300 mmHg. In order to form bisphenol A and an adduct adduct in the following crystallization process, the unreacted phenol contained in a reaction mixture is preferably distilled under the conditions which extract a predetermined amount from a column bottom. Components separated from the top of the distillation column 4 are unreacted acetone, water, methanol contained as impurities, isopropylphenol, unreacted phenol and the like. By controlling the amount of isopropylphenol extracted from the column top, the concentration of the substance in the reaction solution can be adjusted. For example, when the amount of isopropyl phenol in the reaction solution is reduced in the distillation column 4, the amount of recovery of phenol to the top side may be increased, the reflux ratio may be decreased, or the distillation column 4 may be used. The above adjustment can be performed efficiently by performing an operation of supplying phenol from the outside. By such an operation, the amount of isopropylphenol recovered to the top side is usually 0.8% by weight or more, preferably 1.5% by weight or more, relative to the amount of the same substance supplied.

The concentration of bisphenol A in the column bottom liquid after the low boiling point component is separated from the column top is usually 20 to 50% by weight. When the concentration of bisphenol A is lower than 20% by weight, the yield of bisphenol A is lowered, and when the concentration of bisphenol A is higher than 50% by weight, the viscosity of the concentrated liquid mixture becomes high, which makes transportation difficult. The column bottom liquid is transferred to a bisphenol A separation step, and the recovery of the target bisphenol A is performed.

In the case of having the acetone circulation process, the low boiling point component including unreacted acetone, water, phenol, and isopropylphenol separated in the low boiling point component separation process is sent to the acetone circulation process composed of the separation system 20, such as by distillation. Acetone is classified. The fractionated acetone is fed back to the methanol removal apparatus 1a at the front end of the reaction process before being re-supplied as raw material acetone to the reaction system, and it is preferable to remove methanol as an impurity.

In terms of active deterioration of the catalyst, the smaller the amount of methanol, the more preferable. However, in order to remove a small amount of methanol from the raw material acetone, a large equipment such as a plurality of distillation columns, if necessary, is required. The burden is too great to be realistic. In consideration of these, the amount of methanol in the raw material acetone is usually 10 to 500 ppm by weight, preferably 30 to 500 ppm by weight, more preferably 50 to 300 ppm by weight, thereby avoiding an excessive burden on the purification of acetone, The practical operation in which the fall of activity of the is suppressed can be performed.

As the separation system 20, a multi-stage distillation column is usually used. The phenol separated and recovered is usually rectified together with fresh phenol in the purifier 20a, and then stored in a storage tank 22 for clean phenol and used for rinsing the crystal adducts described later. In the refiner 20a, isopropylphenol is spread out of the system by distillation or the like. When isopropyl phenol is spread out of the system by distillation, for example, the temperature is 150 to 190 ° C., the absolute pressure is 300 to 760 mmHg, and the isopropyl phenol contained in the phenol together with the heavy substance contained in the phenol supplied from the outside. Combined, there is a way to spread from the bottom.

<Separation process of bisphenol A>

In the separation process of bisphenol A, the substance containing bisphenol A as a main component is isolate | separated from the component containing bisphenol A obtained by the low boiling point component separation process. The method for separating the substances is not particularly limited and known methods can be employed. Here, the "materials containing bisphenol A as a main component" means the materials containing 50% by weight or more of bisphenol A. Namely, cakes and slurries of bisphenol A and phenol adducts or crystals of bisphenol A alone, solids, liquids, gases, slurries and cake-like substances mainly composed of bisphenol A such as molten bisphenol A or gaseous bisphenol A It means that they may contain impurities such as phenol and reaction by-products. As a method of separating substances, the main component is a substance consisting of a cake of bisphenol A and phenol adduct crystals by crystallization, and a phenol containing reaction by-products such as bisphenol A, 2,4-bisphenol A, and croman. A method of separating into a so-called 'mother liquor' substance is illustrated. A method of separating bisphenol A by adding a third component such as water or acetone to a solution containing bisphenol A, crystallizing the crystals of bisphenol A directly, and not solid-liquid separation, in addition to this method. A distillation column may be used to distill a bisphenol A-containing substance under high vacuum, distillate bisphenol A from the column top, and the like. Hereinafter, as a representative example, the crystallization step and the recovery step of the bisphenol A will be described in the method of separating the adduct crystals of bisphenol A and phenol and the mother liquid by performing solid-liquid separation after crystallization.

<Crystal process>

Crystallization is carried out in the subsequent crystallization step for the column bottom liquid (liquid component containing bisphenol A) from which the low boiling point component is separated in the low boiling point component separation step. In this crystallization step, the column bottom liquid is cooled from 70 to 140 ° C to 35 to 60 ° C in the crystallizer 5, the crystal adduct is crystallized into a slurry, and the slurry is solid-liquid separated in the solid-liquid separator 6. As the analyzer 5, the crystallization tank which has one or several external coolers which can switch operation is used normally. In the case of switching operation by installing a plurality of external coolers, the crystals attached to the inside of the external coolers that are not used are heated and dissolved, and then switched and used to continuously operate the crystallization process while maintaining high capability. have. Moreover, since the crystallization characteristic in a crystallization tank changes at the time of switching of an external cooler, the amount of mother liquid isolate | separated by the solid-liquid separator 6 changes. In order to prevent fluctuation in the amount of mother liquor supplied from the line 15 to the line 1, a part of the mother liquor is usually diverted to the rear side of the reactor 2 via the line 16. When using the crystallization tank provided with the jacket type | mold cooler as the crystallizer 5, it is preferable to provide the scraping-out apparatus which removes the crystal | crystallization adhering to a heat-transfer surface.

<Recovery process of bisphenol A>

The crystal adduct recovered in the solid-liquid separator 6 is redissolved in phenol in the re-dissolver 7 and recrystallized in the re-calculator 8 to increase the purity, and then the solid-liquid separation and rinse system constituted by a centrifuge or the like. In (9) it is solid-liquid separated and rinsed with clean phenol. Then, it is transferred to the crystal adduct decomposition system 11.

In addition, most of the liquid fraction separated from the solid-liquid separation and rinsing system 9 and the rinse waste liquid can be used as the rinse liquid supplied from the redissolver 7 to the crystalline adduct redissolution phenol and the solid-liquid separator 6. Some of the liquid fraction separated in the solid-liquid separation and rinse system 9 is circulated to the tank 14 together with the circulating mother liquor.

In the crystal adduct decomposition apparatus 11, the method of heat-melting a crystal adduct at 100-160 degreeC normally, and distilling most phenols from the obtained melt is used. In the refiner | purifier 12, the method of removing the residual phenol normally and steam-refining bisphenol A by steam stripping etc. is used. This method is described in, for example, Japanese Patent Laid-Open No. 2-28126, Japanese Patent Laid-Open No. 63-132850, and the like.

<Liquid circulation process>

In the present invention, the 'mother liquor' is a bisphenol A separation process in which the bisphenol A-containing substance is removed from the component containing bisphenol A. For example, after the adduct crystallization, the bisphenol A / phenol adduct is separated by a solid-liquid separator. One liquid and the like. A portion of the liquid fraction (mother liquor) solid-liquid separated in the solid-liquid separator 6 (such as 85 to 96%) is reacted before and / or through the line 16 via the line 13 via the line 13. Circulated to the back of the process. In the present invention, the present step is not essential, but by using in combination with the light powder separation step described later, the heavy matter can be efficiently removed and stable operation can be continued.

That is, the composition of the mother liquid obtained from the solid-liquid separator 6 is 5 to 15 weight% of by-products, such as 65 to 85 weight% of phenols, 10 to 20 weight% of bisphenol A, and 2,4'-isomer normally, and 2,4 '. It contains a lot of impurities such as isomers. In order to prevent accumulation of these impurities in the process, a part of the mother liquid obtained from the solid-liquid separator 6 is provided to the hard powder separation process described later. In this case, the molar ratio (phenol / acetone) of phenol to the total amount (a + b) of the fresh acetone amount (a) to line (1) and the recovered acetone amount (b) supplied via line (21) is shown above. A mother liquid delivery pump (not shown) is controlled from the tank 14 to the line 15 so as to have a constant mixing ratio.

Hard powder separation process

In this step, at least a part of the mother liquor separated in the step is separated into hard and heavy powders by heat treatment and distillation in the presence of alkali. Specifically, at least a portion of the mother liquor from the line 13 is separated into the impurity removal line 13 ', and is separated into a hard component and a heavy component in the alkali decomposition column 13a by heat treatment and distillation in the presence of alkali. Preferably, at least a portion of the aliquots of the mother liquor are distilled in the mother liquor concentration column 13c together with a portion of the phenol together with a large amount of isopropylphenol as a light effluent from the top and / or side, followed by heating in the presence of an alkaline substance. Bisphenol A and isomers are decomposed into phenol and isopropenylphenol. Hereinafter, the case where a hard effluent is obtained from a tower top is demonstrated as an example.

Since the phenol recovered from the top of the mother liquid concentration tower 13c contains a large amount of isopropylphenol, at least a part of this liquid is branched and spread out of the system via the line 13d or at least a part of the purifier. The isopropyl phenol concentration in the reaction solution can be adjusted by supplying to (20a) to purify and remove the isopropyl phenol. By carrying out in combination with the separation operation of isopropyl phenol in the distillation column (4), it is possible to adjust the more efficient isopropyl phenol concentration.

Of the phenols recovered from the column top of the mother liquor concentration tower 13c, the phenols which have not been spread out of the system via the line 13d are used for the quench of the column tower of the alkaline decomposition column 13a. The amount of isopropylphenol which is spread out of the system via the line 13d and contained in the phenol is preferably 5% by weight or more and 5 to 20% by weight of the amount of isopropylphenol supplied to the mother liquor concentration tower 123d. More preferably, it is especially preferable that it is 7-15 weight% or more. When the extraction amount of isopropyl phenol is less than the above range, it may be difficult to maintain the content of isopropyl phenol in the reaction solution in a predetermined range in the reaction step. In addition, in order to increase the amount of isopropylphenol spread out of the system via the line 13d, it is necessary to increase the amount of phenol to be spread, which may cause loss of phenol. In particular, when phenol which is not spread out of the system is used for the cooling of the column top of the alkali decomposition tower 13a, the amount of phenol used for the cooling is reduced, resulting in insufficient cooling. There is. When the amount of phenol used for quenching is too small, the concentration of isopropenylphenol in the hard component obtained from the alkali decomposition tower 13a is increased. When the concentration of isopropenyl phenol is high, dimerization of isopropenyl phenol sometimes occurs, and the selectivity in the recombination reaction step described later tends to deteriorate.

In the mother liquor concentration tower 13c, the amount of isopropyl phenol recovered to the top of the outflow column is supplied to the amount of animal matter supplied to the top of the outflow column by increasing the recovery amount of phenol to the top of the column and lowering the reflux ratio. It is 0.6 or more, Preferably you may be 0.8 or more. Moreover, as for the ratio which branches and extracts this effluent liquid, 0.1 or more are preferable. At this time, when it is necessary to adjust the ratio of phenol and isopropenyl phenol by reducing the amount of phenol supplied to the recombination reactor 13b in a later step, the operation of supplying phenol from the outside can also be performed.

The decomposition reaction is preferably performed by a reactive distillation method such as supplying a mother liquor and an alkaline substance to the alkali decomposition column 13a, and heating and decomposing it at 200 to 300 占 폚. As the alkaline substance, known alkaline substances such as hydroxides of alkali metals such as sodium and potassium, carbonates, phenol salts, hydroxides of alkaline earth metals such as magnesium and calcium, and phenol salts can be used. It is preferable to supply in a state. In the alkali decomposition step, the decomposition rate of bisphenol A and the isomer is usually 30% or more, preferably 50% or more, more preferably 60% or more.

As disclosed in Japanese Patent Laid-Open No. 10-218814, the mother liquor may be concentrated beforehand and used for decomposition reaction or may be used for decomposition reaction without concentration. This is because even if the mother liquor is used as it is for the decomposition reaction, the phenol in the mother liquor is immediately evaporated and concentrated. The mother liquor subjected to impurity treatment is alkali-decomposed in the alkali decomposition column 13a, and is separated into a hard component including phenol and isopropenyl phenol and a heavy component such as tar. Heavy content is released out of the system.

Recombination Reaction Process

The hard powder is subjected to the recombination reaction in the recombination reactor 13b. In other words, the isopropenylphenol is a polymerizable material and easily forms a polymer. Therefore, when the hard component containing isopropenyl phenol is recycled to the mother liquid circulation line 13 as it is, the problem arises that the product bisphenol is colored by this polymer. Therefore, the hard component (phenol and isopropenylphenol) which flowed out from the top of the alkali decomposition tower 13a is immediately condensed, it is supplied to the recombination reactor 13b, and a recombination reaction is performed in presence of an acidic ion exchange resin, and a coloring component The production of phosphorus polymer is suppressed.

Recombination reaction is normally performed at the temperature of 50-85 degreeC. As the strongly acidic cation exchange resin used in the recombination reaction, a strong acid cation exchange resin such as a sulfonic acid type is usually used. Moreover, you may use the same thing as the sulfonic acid type strong acid cation exchange resin partially neutralized with the sulfur containing amine compound used at a reaction process.

In the recombination reaction, a side reaction in which the isopropenyl phenol is dimerized occurs, but this side reaction can be remarkably suppressed by setting the molar ratio of phenol to 40 or more of the isopropenyl phenol supplied to the recombination reactor 13b. desirable. In the case where the molar ratio of phenol to isopropenyl phenol is 40 or more, it is preferable to further supply phenol from outside (such as phenol used for washing crystals in the crystallization step).

<Recombination reaction solution circulation process>

The recombination reaction liquid (product of bisphenol A) obtained in the above process is recycled to the mother liquor circulation line 13.

In the method for producing bisphenol A of the present invention, the content of isopropylphenol in the reaction solution in the reaction step is 4% by weight or less, preferably 2% by weight or less, more preferably 1% by weight or less, particularly preferably 0.5% by weight. It is characterized by controlling to% or less. The inventors believe that isopropylphenol (including o-, m-, p-forms and mixtures thereof) contained as impurities in the reaction solution in the reaction step is a substance that promotes active degradation of the acidic ion exchange resin catalyst in the reaction step. I found out. Moreover, it turned out that this isopropyl phenol by-product is heat-processed in presence of alkali in the said impurity treatment process. Therefore, in the production method of bisphenol A having the impurity treatment step, incorporation of isopropylphenol is unavoidable, and the more the impurity treatment is performed, the more isopropylphenol continues to accumulate in the system. Therefore, in this invention, content of isopropyl phenol in reaction liquid is controlled to 4 weight% or less in a reaction process. Thereby, deterioration of an acidic ion exchange resin catalyst can be suppressed in a reaction process. The concentration of isopropylphenol in the reaction liquid in the reaction step may be based on freezing of the reactor inlet, the inside of the reactor, and the outlet of the reactor, but in order to prevent deterioration of the ion exchange resin, the concentration of the isopropylphenol in the reaction solution is preferably adjusted based on the reactor inlet.

As a method of controlling the content of isopropyl phenol in the reaction solution to 4% by weight or less in the reaction step, 5 to 20% by weight of the mother liquor supplied to the hard powder separation step is preferably heavy. It is preferable to isolate | separate as powder. This is based on the inventors' finding that there is a correlation between the amount of alkylphenol produced in the system and the amount of heavy powder (tar powder) discharged from the alkali decomposition tower 13a. As a requirement for adjusting the heavy content discharge, the condensation time, the alkali concentration, the decomposition temperature, the decompression degree, and the like of the mother liquid in the alkali decomposition tower 13a can be adjusted to the above range by appropriately selecting and combining them.

Specifically, the convection time of the mother liquor in the alkali decomposition tower 13a is usually 1 to 20 hours, preferably 2 to 10 hours, and an alkali concentration (alkali concentration in the heavy component removed from the system in the hard powder separation step (metal Sodium conversion)) is usually 100 to 4,000 ppm by weight, preferably 200 to 2,000 ppm by weight, decomposition temperature is usually 170 to 300 ° C, preferably 200 to 250 ° C, and reduced pressure is usually 10 to 100 Torr, preferably Preferably it is 20-50 Torr. In addition, the fraction of the mother liquor fractionated from the line 13 to the impurity removal line 13 'is adjusted, and isopropyl phenol is used at the time of distillation of the phenol carried out in the mother liquor concentration tower 13c before adding alkali. Since it is extracted together with phenol, the isopropyl phenol content in the reaction liquid can be adjusted in the reaction step by changing the outflow rate or by adjusting the amount extracted from the line 13d to the purifier 20a. In particular, the method of adjusting the amount extracted from the line 13d to the refiner 20a is preferable because it can efficiently extract isopropylphenol. In addition, the amount of isopropyl phenol in the reaction solution can be adjusted in the reaction step by adjusting the amount supplied from the recombination reactor 13b to the line 13 and the amount of fresh phenol in the raw material phenol. Moreover, although isopropyl phenol can be removed from the hard powder obtained from the alkali decomposition tower 13a by the distillation, the method of controlling by the operation conditions of the said alkali decomposition tower 13a is preferable because it is simple.

In addition, in the production method of the present invention, in addition to the above operation, the hydrous phenol generated in the dehydration operation at the start of the use of the reaction catalyst is supplied to the distillation column in the process little by little during operation, and dehydration is carried out. It is preferable to reuse because the phenol which is a raw material can be reused.

As described above, as a preferred embodiment of the present invention, condensation reaction proceeds by adding acetone and excess phenol to a reactor filled with a sulfonic acid type ion exchange resin modified with an aminothiol compound, thereby producing bisphenol A. In this case, the sulfonic acid type ion exchange resin catalyst used as a catalyst undergoes a bisphenol A production reaction for a long time, thereby denatures the aminothiol compound acting as a cocatalyst and loses its effect, which is a byproduct on the surface of the ion exchange resin. Degradation of catalytic activity occurs due to adhesion of heavy substances such as tar and the surface of the catalyst. Therefore, it is necessary to extract these catalysts from a reactor and replace them regularly.

The catalyst newly added by exchange may be a newly prepared catalyst, and after the activity is lowered, the used catalyst extracted from the reactor is treated with an acid or the like to remove the surface tar and the modified cocatalyst, and then the aminothiol compound is further removed. The sulfonic acid type ion exchange resin catalyst may be modified by being impregnated with the solution to be contained.

The filling of the ion exchange resin catalyst into the reactor is usually performed in a state in which the ion exchange resin catalyst is swollen with water. Therefore, it is preferable that the charged ion exchange resin catalyst is subjected to dehydration operation before the production reaction of bisphenol A. The dehydration operation of the ion exchange resin is usually performed by removing most of the water and then contacting with phenol. Since the water swelling ion exchange resin rapidly decreases in volume due to dehydration, the ion exchange resin itself may be damaged by the dehydration operation. Therefore, it is preferable to perform an initial dehydration operation using the mixed solution of about phenol / water = 9/1. Since sudden volume change can be suppressed by this operation, breakage of an ion exchange resin, etc. can be prevented.

In the dehydration operation, the contact method of phenol may be impregnated by a batch operation, or phenol may be continuously distributed. The phenol to be used may be purified pure phenol, or may be a filtrate (mother liquor) generated in the solid-liquid separation process circulating in the bisphenol A process.

Since the phenol used in the dehydration operation contains an acidic component desorbed from water or a sulfonic acid type ion exchange resin, it is preferable to purify and reuse it. The method for purifying phenol used in the dehydration operation is not particularly limited, and there are a method of purifying by collecting in a tank or the like and recirculating into the process little by little into the process, or by using a dedicated distillation column. In addition, when two or more reactors are installed and operated in parallel, dehydration treatment of one or more reactors being stopped at the same time while operating at least one reactor is carried out simultaneously, and the crude phenol generated at that time is introduced into the process. You may recycle.

In the case of recycling into the process, it may be supplied to a distillation column of a low boiling point component separation step for removing unreacted acetone, water, and the like downstream of the reactor, or may be supplied before impurity removal treatment to purify phenol. Moreover, you may perform in combination of these. Generally, since acidic components contained in the crude phenol may be included in the product bisphenol A, it is preferable to supply before the impurity removal treatment, but the phenol having a high water content generated at the beginning of the dehydration operation is supplied to the impurity removal treatment. When water is mixed into the alkali decomposition tower of the impurity removal treatment, the operation of the alkali decomposition process operating under the conditions of high temperature (200 ° C or higher) and high pressure reduction (80 mmHg or less) results in high pressure reduction due to the vapor pressure of the mixed water. This may not be maintained and may be difficult. Therefore, it is preferable to process the phenol which has a high water content in the initial stage of dehydration operation in a low boiling point component separation process, and to switch to supply before impurity removal processing at the time when the water content in phenol becomes small.

Purified phenol is used in phenol for washing adduct crystals in solid-liquid separation processes.

1 is a flow chart showing a method for producing bisphenol A of the present invention.

2 is a flowchart showing a pilot used in Example 1. FIG.

Explanation of the sign

1a: methanol removal device

2: reactor

4: distillation column

5: crystallizer

6: solid-liquid separator

7: remelting

8: Refining Stone

9: Solid-liquid Separation and Rinse System

11: Crystal Adduct Decomposer

12: Purifier

13a: alkali decomposition tower

13b: recombination reactor

13c: mother liquor concentration tower

14: tank

20: Separation system

20a: purifier

22: phenol storage tank

Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.

(1) Analysis method of acetone:

A gas chromatography apparatus (GC-14B manufactured by Shimadzu Seisakusho) equipped with a Fused Silica Capillary column and a TCD detector was used.

(2) Analysis method of isopropylphenol:

A gas chromatography apparatus (GC-14B manufactured by Shimadzu Seisakusho) equipped with a fused silica capillary column and a FID detector was used.

(3) Acetone conversion rate:

Obtained by the following formula:

Acetone conversion (%) = {[(Feed rate of raw acetone: kg / h)-(Acetone concentration% by weight of line (3)) / 100 x (Liquid amount in line (3): kg / h)] / (( Supply of raw material acetone: kg / h} x 100

Example 1:

Bisphenol A was continuously produced by a pilot test facility having the flow shown in FIG. The diameter of the reactor 2 provided in the reaction step is 660 mm, and sulfonic acid type cation exchange resin ("Dionion SK-104H" manufactured by Mitsubishi Chemical Co., Ltd.) as 2-catalyst is used as a catalyst. Thiol was charged with 340 L of ion exchange resin modified with 20 mol% of sulfonic acid groups. In the reactor (2) filled with the catalyst, a mixture of the mother liquor and acetone (82 wt% phenol, 4 wt% acetone, 8 wt% bisphenol A and 6 wt% other components) Methanol content is 100 ppm by weight) was supplied at a flow rate of 400 kg / h, and the reaction was carried out at 65 ℃. The liquid from the line 3 was supplied to the distillation column 4 equipped with the packing so that the theoretical stage became 7 stages, and 62 kg / h was extracted to the tower top. At this time, the amount of isopropylphenol extracted from the column top of the distillation column 4 was 1.6% by weight of the supplied amount. The column bottom liquid of the distillation tower 4 was supplied to the crystallization tower 5, and crystallized the adduct crystals of bisphenol A and phenol. The obtained adduct crystals contained purified phenol (120 kg / h) used for rinse and separated into solid (78 kg / h) and mother liquor (385 kg / h) in the solid-liquid separator 6. The liquid from the line 13 'was supplied to the mother liquid concentration tower 13c equipped with the packing material so that it could become three theoretical stages, and 29 kg / h was extracted to the tower top. 11% of this liquid was branched and the isopropyl phenol was removed by draining out of the system from the line 13d. At this time, the off-system discharge of isopropyl phenol was 10% by weight of the amount supplied to the mother liquid concentration tower (13c).

347 kg / h (90 wt% of the total amount of the mother liquor) in the mother liquor was recombined into the reaction process as it was through the line 13, while the remaining 38 kg / h (10 wt% of the total amount of the mother liquor) was added to the mother liquor concentration tower ( After the treatment in 13c), the column top liquid and the column bottom liquid not discharged out of the system were fed to the alkali decomposition column 13a to remove impurities. In the alkali decomposition tower 13a, 0.22 kg / h of 25 wt% aqueous sodium hydroxide solution was added, followed by alkali decomposition and distillation under conditions of a temperature of 210 ° C., a pressure of 40 Torr, and a convection time of 4 hours, and a heavy powder of 3.8. kg / h (10 wt% of heavy powder purge) were separated. The hard powder from which heavy powder (tar powder) has been removed is a recombination reactor filled with a sulfonic acid type cation exchange resin ("Diaion SK-104H" manufactured by Mitsubishi Chemical Co., Ltd.) not modified with a sulfur-containing amine compound maintained at 65 ° C. 13b), the isopropenylphenol produced in the alkali decomposition reaction was reacted with phenol to make bisphenol A, and then fed back to the reaction system via line (13).

The operation was continued for 4,000 hours. After 250 hours from the start of operation, the amount of impurities in the system was stable, and there was no change in the amount of impurities until 4,000 hours thereafter. The concentration of p-isopropylphenol in the raw material supplied to the reactor 2 at that time was 0.3% by weight, and the isopropylphenol extracted from the column top of the distillation column 4 was 1.5% by weight of the supplied isopropylphenol, line 13d. The isopropyl phenol discharged out of the system was 10% by weight of the isopropyl phenol supplied to the mother liquor concentration tower 13c. Moreover, the acetone conversion rate became 98.5% 1 hour after the start of acetone supply, and it became 93.1% after 4,000 hours of operation.

Example 2:

The same operation as in Example 1 was carried out except that a part of the effluent of the mother liquid concentration tower 13c was not discharged from the line 13d to the outside of the system. Was stable at 0.8% by weight. The conversion rate of acetone was 98.5% one hour after the start of acetone supply, and then 91.8% by 4,000 hours of operation.

Example 3:

The same operation as in Example 1 was carried out except that the isopropylphenol was not discharged out of the system from the distillation column 4, and the concentration of isopropylphenol in the raw material supplied to the reactor 2 was 1.2% by weight. It was stable. The conversion rate of acetone was 98.5% one hour after the start of acetone supply, and then 90.4% by 4,000 hours of operation.

Example 4:

The same operation as in Example 1 was carried out except that acetone containing 650 ppm by weight of methanol was used as the reaction raw material. The concentration of isopropylphenol in the raw material supplied to the reactor 2 was stable at 0.4% by weight. The conversion rate of acetone became 98.0% 1 hour after the start of acetone supply, and after that, it became 88.6% by 4,000 hours of operation.

Example 5:

In the hard powder separation step, the temperature of the alkali decomposition tower 13a is set at 250 ° C., and the heavy powder to be separated is 0.9 kg / h (2.3 wt% of heavy powder spreading), and the line 13d is formed from the top of the mother liquor concentration tower 13c. The amount of isopropyl phenol that is diffused through) is 20% by weight of the amount supplied to the mother liquor concentration tower 13c, and the amount of isopropyl phenol extracted from the column top is supplied to the distillation column 4. The same operation as in Example 1 was carried out except that the amount was 2.5% by weight, and the concentration of isopropylphenol in the raw material supplied to the reactor 2 was stable at 2.1% by weight. The conversion rate of acetone became 98.5% 1 hour after the start of acetone supply, and after that, it became 88.3% by 4,000 hours of operation.

Comparative Example 1:

In Example 1, operation was performed under the same conditions as in Example 1 except that the reaction distillation conditions by alkali decomposition were changed and the reaction and distillation were performed at 250 ° C. Since the alkali decomposition temperature was higher than that of Example 1, alkali decomposition proceeded more as compared with Example 1, and the amount of heavy component removed at the bottom was reduced to 0.8 kg / h (2.3 weight percent of heavy powder spreading). . After 250 hours from the start of operation, the amount of impurities in the system was stable, and there was no change up to 4,000 hours thereafter. At that time, the concentration of isopropylphenol in the raw material to be supplied to the reactor 2 was 6.3% by weight. The acetone conversion rate was 98.5% one hour after the start of acetone supply, and after that, the acetone addition rate was greatly decreased, and the deterioration of the sulfonic acid type cation exchange resin catalyst was remarkably confirmed.

Comparative Example 2:

The same operation as in Comparative Example 1 was carried out except that acetone containing 650 ppm by weight of methanol was used as the reaction raw material. The concentration of isopropylphenol in the raw material supplied to the reactor 2 was stable at 6.3% by weight. The acetone conversion rate was 97.5% one hour after the start of acetone supply, and then 71.1% by 4,000 hours of operation.

TABLE 1

Reaction solution Hard powder
Separation Process Low boiling point
ingredient
Separation Process
Reaction Process
Acetone conversion rate Isopropylphenol
density Heavy powder
Purge rate Outside of isopropyl phenol
Emissions Extraction amount of isopropylphenol Methanol Concentration in Acetone
1 hour later
After 4,000 hours weight% weight% weight% weight% Weight ppm % % Example 1 0.3 10 10 1.6 100 98.5 93.1 Example 2 0.8 10 0 1.6 100 98.5 91.8 Example 3 1.2 10 10 0 100 98.5 90.4 Example 4 0.4 10 10 1.6 650 98.0 88.6 Example 5 2.1 2.3 20 2.5 100 98.5 88.3 Comparative Example 1 6.3 2.3 10 1.6 100 98.5 80.9 Comparative Example 2 6.3 2.3 10 1.6 650 97.5 71.1

As mentioned above, although this invention was demonstrated regarding embodiment which is considered to be the most practical and desirable at this time, this invention is not limited to embodiment disclosed in this specification, Comprising: It is an invention understood from the Claim and the whole specification. Modifications can be made appropriately without departing from the spirit or spirit of the invention, and should be understood to be accompanied by such modifications as the technical scope of the present invention.

According to the bisphenol A production catalyst of the present invention, the activity of the production catalyst of bisphenol A in the method for producing bisphenol A having a step of impurity treatment of at least a part of the mother liquor obtained in the bisphenol A separation step and re-feeding to the reaction system. Can be prevented from deteriorating.

Claims (7)

A reaction process of reacting acetone of a raw material component with phenol in the presence of an acidic ion exchange resin catalyst to obtain a reaction mixture containing bisphenol A and phenol, and the reaction mixture as a low boiling point component containing a component containing bisphenol A and unreacted acetone. Low-boiling point component separation step for separating, Bisphenol A separation step for separating the component containing bisphenol A into a bisphenol A-based substance, and a mother liquor containing phenol and a reaction by-product as a main component, at least the separated mother liquid The process of separating the hard powder and the heavy component by heat treatment and distillation in the presence of alkali, and the separated hard component are treated in the presence of an acidic ion exchange resin catalyst to recombine the phenol and isopropenylphenol in the hard component. Recombination reaction step to convert to bisphenol A, Recycling reaction of the recombination reaction solution to the reaction step A method for producing the sum of bisphenol A comprising the reaction liquid circulating step at least, the method for producing bisphenol A of the content of isopropyl phenol in the reaction solution from the reaction step, characterized in that the control to not more than 4% by weight. The method for producing bisphenol A according to claim 1, wherein the acidic ion exchange resin catalyst in the reaction step is a modified acidic ion exchange resin catalyst modified with alkylaminothiol. The method for producing bisphenol A according to claim 2, wherein the alkylaminothiol is 2-aminoethanethiol and / or 2- (4-pyridyl) ethanethiol. The method for producing bisphenol A according to any one of claims 1 to 3, wherein in the hard powder separation step, an amount corresponding to 5 to 20% by weight of the mother liquor supplied to the hard powder separation step is separated as a heavy powder. . The hard powder separation process according to any one of claims 1 to 3, wherein the hard powder separation step has a mother liquor concentration tower prior to the heat treatment, and at least a part of the hard effluent obtained from the mother liquid concentration tower is spread out, so as to harden the separation process. A method for producing bisphenol A, wherein at least 5% by weight of isopropylphenol supplied to the mother liquor concentration tower is extracted when extracted from the mixture. The method for producing bisphenol A according to any one of claims 1 to 3, wherein at least 0.8 wt% of the isopropylphenol supplied is separated together with the low boiling point component in the low boiling point component separation step. The method for producing bisphenol A according to any one of claims 1 to 3, wherein the amount of methanol contained in acetone of the raw material component supplied to the reaction step is 10 to 500 ppm by weight.

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