WO2003043964A1

WO2003043964A1 - Process for producing bisphenol a and apparatus therefor

Info

Publication number: WO2003043964A1
Application number: PCT/JP2002/011882
Authority: WO
Inventors: Masahiro Kodama; Kazuyuki Hirano; Norio Ogata; Hideaki Masaki; Akio Suwa
Original assignee: Idemitsu Petrochemical Co., Ltd.
Priority date: 2001-11-22
Filing date: 2002-11-14
Publication date: 2003-05-30
Also published as: TW200303856A

Abstract

In a process for producing bisphenol A which comprises the reaction step, the step of removing low-boiling components, the concentration step, the crystallization/solid-liquid separation step, the heat melting step, the phenol-removal step, and the granulation step, at least a portion of bisphenol A withdrawn from the phenol-removal step depending on the treatment capacity of the granulation step is transferred to somewhere (for example, the concentration step) other than the granulation step. Owing to the above process, in case of the occurrence of some troubles in the granulation step during the production of bisphenol A, it becomes unnecessary to stop the operation of the apparatus other than the granulation unit and bisphenol A formed till the stop of the operation in the granulation unit can be effectively utilized without wasting. Moreover, the time required until the start of normal operation in the granulation unit can be shortened thereby.

Description

TECHNICAL FIELD The manufacturing method and apparatus of bisphenol A

The present invention relates to an improved method for producing bisphenol A [2,2-bis (4-hydroxyphenyl) pulp bread] and an apparatus used therefor. More specifically, the present invention is capable of simultaneously producing a molten product and a granular product of bisphenol A, and is capable of simultaneously operating a device other than the granulation system in the event of an abnormality such as a trouble in the granulation process. In addition to this, bisphenol A generated when the granulation system is stopped can be effectively used without waste, and the time required for steady operation when the granulation system is restarted can be shortened. The present invention relates to an advantageous method for producing bisphenol A, and an apparatus for producing bisphenol A used in this method. Background art

Bisphenol A is known to be an important compound as a raw material for engineering plastics such as polycarbonate resin and polyarylate resin, or epoxy resin, and its demand has been increasing in recent years. . This bisphenol A is produced by condensing excess phenol and acetone in the presence of an acidic catalyst and optionally a cocatalyst such as a sulfur compound.

As the acid catalyst used in this reaction, inorganic mineral acids such as sulfuric acid and hydrogen chloride have conventionally been used, but in recent years, cation exchange resins have attracted attention (UK Patent No. 8422209). Nos. 8495655 and 883391), which have been used industrially.

On the other hand, as a sulfur compound used as a cocatalyst, alkyl mercaptans having or not having a substituent such as methyl mercaptan, ethyl mercaptan, and thiodaricholic acid are known to be effective (U.S. Pat. Nos. 3,592,242 and 2,775,620. This mercaptan is It has the effect of increasing the reaction rate and increasing the selectivity. For example, in the production of bisphenol A, 2- (2-hydroxyphenolene) -12- (4-hydroxyphenolinole) propane (o, -isomer) is mainly produced as a reaction by-product, and trisphenol , Polyphenols and the like are produced. In particular, when used as a raw material for a polycarbonate resin, a polyarylate resin, or the like, bisphenol A with high purity and low content of these by-products is required. For this reason, mercaptans are used as a co-catalyst in order to increase the reaction rate, suppress the generation of the by-products, and increase the selectivity.

In the production process of bisphenol A, a granulation step is usually provided in order to correspond to various applications, and heat-melted bisphenol A is granulated into a particulate product. In this granulation process, for example, a granulation device such as a spray dryer is used, and granulation is performed by converting bisphenol A into droplets and then cooling and solidifying the droplets.

By the way, in the bisphenol A production equipment, since the melting point of the raw material phenol and the product bisphenol A is high, it is easy for troubles due to the formation of solids, etc., to occur. Some ingenuity has been devised. For example, in the granulation process of bisphenol A, the above-mentioned trouble is likely to occur, and therefore, various measures are taken in advance to remove the caustic fine powder or to prevent fine powder reagglomeration. Occlusion could not be completely prevented, and shutting down the Bisphenol A unit often led to undesirable situations. At this time, bisphenol A remaining in the equipment had to be transferred to the intermediate tank / slop tank. In this case, the molten bisphenol A can be reused, but the quality deteriorates due to coloration due to storage at high temperature, etc., so it needs to be purified again.Excessive heating and passing the bisphenol A repeatedly through the purification equipment It is economically unfavorable, and in some cases, it can be transferred to a slop tank and used only as tar, causing problems such as a significant increase in economic loss.

Furthermore, if the operation of Bisphenol A production equipment is completely stopped, it will inevitably take a considerable amount of time to return to normal operation. In addition, when a manufacturing equipment using bisphenol A as a raw material, such as a polycarbonate resin manufacturing plant or an epoxy resin manufacturing plant, is installed nearby, molten bisphenol A products are more likely to be used than granular bisphenol A products. It may be economically advantageous to transport the product through piping. Disclosure of the invention

Under such circumstances, the present invention can simultaneously produce a molten product and a granular product of bisphenol A, and can stop the operation of devices other than the granulation system in the event of an abnormality such as a granulation process trouble. In addition, it is industrially advantageous, such as bisphenol A generated when the granulation system is stopped can be used effectively without waste, and the time until steady operation can be shortened when the granulation system is restarted. It is an object of the present invention to provide a method for producing bisphenol A, and an apparatus for producing bisphenol A used in this method.

The present inventors have conducted intensive studies to achieve the above object, and as a result, a method for producing bisphenol A having a step of heating and melting an adduct of bisphenol A and phenol, a step of removing phenol, and a step of granulating. A method of transferring at least a part of the bisphenol A in a molten state obtained in the dephenol removal step, that is, a part or all of the bisphenol A to the outside of the granulation step according to the treatment capacity in the granulation step; and It has been found that the objectives can be achieved by a practicable device.

Further, the present inventors have proposed a method for producing bisphenol A including a reaction step, a low boiling point component removing step, a concentration step, a crystallization-solid-liquid separation step, a heat melting step, a dephenol step, and a granulation step. Depending on the processing capacity in the granulation process, at least a part of bisphenol A extracted from the phenol removal step, that is, a method of returning part or all of the bisphenol A to the concentration step, and a device capable of performing the method, may be used. It has been found that the object can be better achieved.

The present invention has been completed based on such findings.

That is, the present invention

(1) After the adduct of bisphenol A and phenol is heated and melted in the heating and melting step, the resulting liquid mixture is dephenolized in the dephenol step. To obtain bisphenol A in the molten state, and then granulate in the granulation step to produce bisphenol A. In the method for producing bisphenol A, the molten state obtained in the A method for producing bisphenol A, wherein at least part of bisphenol A is transferred outside the granulation step.

(2) An adduct of bisphenol A and phenol is used to obtain a reaction mixture containing bisphenol A by a reaction step of condensing phenol and acetone, and then a low-boiling component removing step, a concentration step, and crystallization are performed. The method for producing bisphenol A according to the above (1), which is obtained by sequentially performing a solid-liquid separation step,

(3) After obtaining a reaction mixture containing bisphenol A by a reaction step of condensing phenol and acetone, a low-boiling component removing step, a concentration step, a crystallization / solid-liquid separation step, and a heating and melting step are added to the reaction mixture. In the method of producing bisphenol A by sequentially performing the phenol removal step and the granulation step, at least a portion of the bisphenol A extracted from the phenol removal step depends on the processing capacity in the granulation step. A process for producing bisphenol A, wherein

(4) Bisphenol A in a molten state obtained by a dephenolizer in an apparatus for producing bisphenol A having a device for heating and melting an adduct of bisphenol A and phenol, a dephenolizer and a granulator Bisphenol A production equipment characterized by providing a pipe for transferring A out of the granulator,

(5) Production of bisphenol A having a reaction device for condensing phenol and acetone, a low-boiling component removal device, a concentration device, a crystallization / solid-liquid separation device, a heating and melting device, a dephenol device, and a granulation device In the apparatus, a pipe for returning the bisphenol A extracted from the dephenol unit to the concentrator is provided between the outlet of the dephenol unit and the inlet of the concentrator. Le A manufacturing equipment,

(6) The method for producing bisphenol A according to (3), wherein the amount of acetone to be introduced into the reaction step is adjusted according to the amount of bisphenol A returned to the concentration step.

(7) The bisphenol A in the molten state, which is transferred outside the granulation process, is The method for producing bisphenol A according to the above (1) or (2), wherein the bisphenol A is mixed or dissolved in an aqueous sodium solution,

(8) When trouble occurs in the granulation step, at least a part of the bisphenol A in a molten state obtained in the dephenol removal step is transferred to another manufacturing apparatus using the bisphenol A as a raw material. , (2) or (7), the method for producing bisphenol A,

(9) At least a part of the bisphenol A extracted from the dephenol removal step is returned to the concentration step, and at least a part of the remaining bisphenol A is transferred to another manufacturing apparatus using the bisphenol A as a raw material. Transporting, characterized in that

(3) the method for producing bisphenol A according to

(10) The method for producing bisphenol A according to the above (8) or (9), wherein the other production apparatus using bisphenol A as a production raw material is a polycarbonate production apparatus or an epoxy resin production apparatus.

(11) Mix or dissolve molten bisphenol A to be transported out of the granulator together with water or sodium hydroxide aqueous solution, together with piping to transport the molten bisphenol A out of the granulator. The apparatus for producing bisphenol A according to the above (4), further comprising a mechanism for causing

Is provided. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing an example of steps in the method for producing bisphenol A of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

In the method for producing bisphenol A according to the present invention, a reaction mixture containing bisphenol A is obtained by a reaction step of condensing phenol and acetone, and then a low-boiling-point component removing step, a concentration step, Bisphenol A is produced by sequentially performing the precipitation-solid-liquid separation step, the heat melting step, the phenol removal step, and the granulation step. Next, each step in the method for producing bisphenol A will be described. (A) Reaction process

In this reaction step, excess phenol and acetone are condensed in the presence of an acidic catalyst to form bisphenol A. As the acidic catalyst, an acid-type ion exchange resin can be used. The acid-type ion-exchange resin is not particularly limited, and those conventionally used as catalysts for bisphenol A can be used, but sulfonic-acid-type cation-exchange resins are particularly preferred from the viewpoint of catalytic activity and the like. It is.

The sulfonic acid type cation exchange resin is not particularly limited as long as it is a strongly acidic cation exchange resin having a sulfonic acid group. Acid resin, benzene honolemualdehyde sulfonic acid resin and the like. Each of these may be used alone or in combination of two or more. -In the method of the present invention, mercaptans are usually used in combination with the acid-type ion exchange resin as a cocatalyst. This mercaptan refers to a compound having an SH group in a free form in the molecule. Examples of such a compound include an alkyl mercaptan and one or more substituents such as a carboxyl group, an amino group, and a hydroxy group. And mercapto alcohol. Examples of such mercaptans include methyl mercaptan, ethyl mercaptan, thiocarboxylic acids such as n-thioglycolic acid and monomercaptopropionic acid, aminoalkanethiols such as 2-aminoethanethiol, and mercapto alcohols such as mercaptoethanol. Among them, alkyl mercaptan is particularly preferable in view of its effect as a cocatalyst. Further, these merbutanes may be used alone or in combination of two or more. These mercaptans can be immobilized on the acid-type ion exchange resin to function as a catalyst. The amount of the mercaptans is generally against acetone raw material, 0.1 to 20 mole ^_0/0, preferably, selected in the range from 1 to 10 mol%.

Although there is no particular limitation on the ratio of phenol to acetone, it is desirable that the amount of unreacted acetone be as small as possible in view of the ease of purification and economical efficiency of the generated bisphenol A. It is advantageous to use the phenol in excess of the stoichiometric amount. Usually, 3 to 30 moles, preferably 5 to 15 moles of phenol are used per mole of acetone. In the production of bisphenol A, the reaction solvent is generally not required, except that the reaction solution is reacted at a low temperature at which the viscosity of the reaction solution is too high or the solidification makes the operation difficult.

The condensation reaction between phenol and acetone in the present invention may be either a batch type or a continuous type. In a reaction tower filled with an acid-type ion-exchange resin, phenol, acetone and mercaptans (mercaptans are used as an acid). It is advantageous to use a fixed bed continuous reaction system in which is continuously supplied (when not immobilized on a type ion exchange resin) to react. At this time, one or more reaction towers may be arranged in series, but industrially, two or more reaction towers filled with an acid-type ion exchange resin are connected in series and fixed. It is particularly advantageous to employ a multi-bed continuous reaction system. The reaction conditions in the fixed bed continuous reaction system will be described.

First, the molar ratio of acetone to phenol is usually selected from the range of 1Z30 to 1/3, preferably 1/15 to 1/5. If the molar ratio is smaller than 1/30, the reaction rate may be too slow. If the molar ratio is larger than 1/3, the generation of impurities increases, and the selectivity of bisphenol A tends to decrease. On the other hand, when the mercaptans are not immobilized on the acid-type ion exchange resin, the molar ratio of the mercaptans / aceton is usually selected from the range of 0.1 / 100 to 20/100, preferably 1/100 to 10/100. It is. If the molar ratio is less than 0.1 / 10 °, the effect of improving the reaction rate and the selectivity of bisphenol A may not be sufficiently exhibited.If the molar ratio is larger than 2 OZl 00, the effect is improved in proportion to the amount. Is rarely recognized.

The reaction temperature is usually 40 to 150 ° C, preferably 60 to 110 ° C. Is chosen. If the temperature is lower than 40 ° C, the reaction rate is low, the viscosity of the reaction solution is extremely high, and in some cases, there is a possibility of solidification.If the temperature exceeds 150 ° C, the reaction control becomes difficult, and bisphenol A ( In addition, the selectivity of ρ, '-isomer) decreases, and the acid type ion exchange resin of the catalyst may decompose or deteriorate. Further, the LHSV (liquid hourly space velocity) of the raw material mixture is usually 0.2 to 30 hr, preferably 0.5 to 30 hr.

~: Selected within the range of L 0 h r.

(B) Low boiling point component removal process

In the low-boiling-point component removing step, the reaction mixture containing bisphenol A obtained in the reaction step (A) is substantially free of an acid-type ion-exchange resin, that is, a batch reaction method. In such a case, the catalyst is removed by filtration or the like, and in the case of a fixed bed continuous reaction system, a treatment for removing low boiling components is performed as it is. In this step, generally, first, unreacted acetone, by-product water, and low-boiling substances such as alkylmercaptan are removed by distillation under reduced pressure using a distillation column.

This vacuum distillation is generally carried out under the conditions of a pressure of about 6.5 to 80 kPa and a temperature of about 70 to 180 ° C. At this time, the unreacted phenol azeotropes, and a part of the phenol is removed from the distillation tower from the top together with the low-boiling substances. In this distillation, the temperature of the heating source used is desirably 190 ° C or less to prevent the thermal decomposition of bisphenol A. In general, SUS304, SUS316 and SSUS316L are used as materials for the equipment.

(C) Concentration step

In this concentration step, bisphenol A is concentrated by subjecting the bottom liquid containing bisphenol A and phenol, etc., from which the low-boiling substances have been removed from the reaction mixture, to distillation under reduced pressure to distill off phenol and to concentrate bisphenol A. Although there are no particular restrictions on the concentration conditions, usually conditions of a temperature of about 100 to 170 ° C and a pressure of about 5 to 70 kPa are employed. If this temperature is lower than 100 ° C, a high vacuum is required, and if it is higher than 170 ° C, extra heat removal is required in the next crystallization step, which is not preferable. The concentration of bisphenol A in the concentrated residual liquid is preferably 20 to 50 weight ^_0/0, more preferably 20 to 40 wt. / ₀ range. Bisufu Roh at this concentration is less than 20 weight ^_0/0 If the recovery rate of the catalyst A is low and exceeds 50% by weight, it may be difficult to transfer the slurry after crystallization.

• (D) Crystallization · Solid-liquid separation process

In this crystallization-solid-liquid separation step, a 1: 1 adduct of bisphenol A and phenol (hereinafter sometimes referred to as phenol adatat) may be obtained from the concentrated residual liquid obtained in the concentration step of the above step (C). ) Is a step of crystallization and separation. In this step, first, the above-mentioned concentrated residue is cooled to about 40 to 70 ° C., and phenol adduct is crystallized to form a slurry. The cooling at this time may be performed by using an external heat exchanger, or by a vacuum cooling crystallization method in which water is added to the concentrated residual liquid and cooling is performed using the latent heat of evaporation of water under reduced pressure. Is also good. In this vacuum cooling crystallization method, about 3 to 20% by weight of water is added to the concentrated residue, and crystallization is carried out at a normal temperature of 40 to 70 ° C and a pressure of 3 to 13 kPa. Processing is performed. If the amount of water added is less than 3% by weight, the heat removal ability is not sufficient, and if it exceeds 20% by weight, the dissolution loss of bisphenol A increases, which is not preferable. In such a crystallization operation, if the crystallization temperature is less than 40 ° C, the viscosity of the crystallization liquid may increase or solidify, and if it exceeds 70 ° C, the dissolution loss of bisphenol A increases. Is not preferred.

Next, the slurry containing phenol adduct thus crystallized is separated into a phenol adduct and a crystallization mother liquor containing reaction by-products by known means such as filtration and centrifugation. This crystallization mother liquor may be partially recycled to the reactor as it is, or partially or entirely subjected to alkali decomposition treatment, and recovered as phenol and isopro- phenylol. In addition, a part or all of the compound can be isomerized and recycled as a raw material for crystallization.

It is effective to repeat this crystallization-solid-liquid separation step several times to obtain a high-purity product. That is, after crystallization, the following phenolic adduct obtained by solid-liquid separation should be subjected to the following steps (D,).

(D ') Dissolution and crystallization of phenol adduct' Solid-liquid separation process

In this step, the phenol adduct crystallized and separated in the step (D) is dissolved using a phenol-containing solution. The phenol-containing solution used in this step is not particularly limited, and may be, for example, the concentration step in step (C). The recovered phenol obtained in Step (C), the washing liquid for the phenol adduct formed in the crystallization / solid-liquid separation step in Step (D), and the solid-liquid separation of the crystallized phenol duct formed in the steps following Step (D ') And the washing solution of the phenol product.

In this step, the above-mentioned phenol-containing solution is added to the phenol adduct obtained in the step (D), and the mixture is heated to about 80 to 110 ° C., and the phenol adduct is heated and dissolved to form a crystal. A bisphenol A-containing solution having a preferred bisphenol A concentration for the precipitation operation is prepared. The bisphenol A-containing solution thus prepared has a low viscosity even at a relatively low temperature and is relatively easy to handle, and is suitable for performing solid-liquid separation of the crystallized phenol adduct with a filter.

Next, the phenol duct is crystallized and solid-liquid separated from the bisphenol A-containing solution obtained as described above, and the phenol adduct is further dissolved using the phenol-containing solution. Repeat at least once.

(E) Heat melting process

This heating and melting step is a step of heating and melting the phenol adduct that has been crystallized and separated in the above step (D) or (D ′), and then distilling off the phenol. In this step, first, the phenol adduct is heated to about 100 to 160 ° C. and melted to form a liquid mixture, and then the phenol is distilled off under reduced pressure to remove the bisphenol A in a molten state. to recover. The vacuum distillation is generally performed under the conditions of a pressure of 1.3 to 13 kPa and a temperature of 150 to 190 ° C. Residual phenol can be further removed by steam stripping.

(F) Granulation process

In this granulation step, the bisphenol A in a dissolved state obtained in the above step (E) is formed into droplets by a granulation device such as a spray drier and cooled and solidified to obtain a product. The droplets are formed by spraying or spraying, and are cooled by nitrogen, air, or the like. A feature of the method for producing bisphenol A of the present invention is that at least a part of the bisphenol A in a molten state obtained in the dephenolization step, that is, Is to transfer the whole to the outside of the granulation process according to the processing capacity in the granulation process.

In this way, part or all of the bisphenol A in the molten state obtained in the dephenol removal step is transferred to the outside of the granulation step according to the processing capacity in the granulation step, thereby preventing troubles in the granulation step. In the event of an abnormality, the operation of the equipment other than the granulation system need not be stopped, and the bisphenol A generated when the granulation system is stopped can be effectively used without waste.

In the method for producing bisphenol A of the present invention, a typical mode of transferring at least a part of the bisphenol A in a molten state obtained in the dephenol removal step to the outside of the granulation step is a bisphenol A extracted from the dephenol removal step. This means that at least a part of phenol A, that is, a part or the whole amount, is returned to the concentration step. In this case, the concentration of bisphenol A in the liquid to be concentrated in the concentration step is adjusted to a desired value by adjusting the amount of acetone introduced into the reaction step according to the amount of bisphenol A returned to the concentration step. Can be adjusted.

In this way, by returning at least a portion of the bisphenol A extracted from the phenol removal step to the concentration step according to the processing capacity in the granulation step, abnormalities such as troubles in the granulation step can be achieved. '' It is not necessary to stop the operation of the equipment other than the granulation system, and it is possible to remanufacture the bisphenol A remaining in the equipment and to stabilize the bisphenol A concentration in the reaction mixture quickly. When the granulation system is restarted, the time until steady operation can be shortened.

In the method of the present invention, the bisphenol A in a molten state to be transported out of the granulation step can be mixed or dissolved in water or an aqueous sodium hydroxide solution as needed.

In the method for producing bisphenol A according to the present invention, at least a portion of the bisphenol A in a molten state obtained in the dephenol removal step is transferred outside the granulation step. At the time of occurrence, at least a part of the bisphenol A in a molten state obtained in the dephenol removal step is to be transferred to another manufacturing apparatus using the bisphenol A as a raw material. Examples of such a production apparatus include a polycarbonate production apparatus using bisphenol A as a raw material and a polycarbonate production apparatus. An epoxy resin manufacturing apparatus can be preferably mentioned. Also in this case, the bisphenol A in the molten state to be transferred can be mixed or dissolved in water or an aqueous sodium hydroxide solution as required.

When bisphenol A in a molten state is dissolved in an aqueous sodium hydroxide solution, the temperature of the aqueous sodium hydroxide solution is preferably in the range of 20 to 80 ° C.

If the temperature is lower than 20 ° C, it takes a long time to dissolve bisphenol A, and if the temperature is higher than 80 ° C, bisphenol A is colored and the aqueous sodium hydroxide solution causes corrosion of equipment materials. There is a risk. The concentration of hydroxide Natoriumu solution is generally 2-4 0 weight ^_0/0 approximately, also the amount used, relative to bisphenol A 1 molar, N a OH is from 1.9 to 2.5 moles of It is better to select it within the range. '

When bisphenol A in a molten state is mixed with water or an aqueous solution of sodium hydroxide, a line mixer or a dissolution tank with a stirrer can be used. At the time of mixing by the device, if necessary, the air in the device may be replaced with an inert gas such as nitrogen gas in advance.

In the method for producing bisphenol A of the present invention, another typical embodiment of transferring at least a part of the bisphenol A in a molten state obtained in the dephenolization step to the outside of the granulation step is a step of removing from the dephenol step. At least a part of the bisphenol A is returned to the concentration step, and at least a part of the remaining bisphenol A is converted to another manufacturing apparatus using the bisphenol A as a raw material, such as a polycarbonate resin manufacturing apparatus or an epoxy resin manufacturing apparatus. It is to be transferred to equipment. For this purpose, it is preferable to provide a pipe for transferring bisphenol A to a production apparatus using bisphenol A as a raw material, in the middle of the pipe for returning bisphenol A to the concentrator. When a manufacturing apparatus using bisphenol A as a raw material is installed nearby, it is more economical to transfer the molten bisphenol A product via piping than the granular bisphenol A product. It may be advantageous to

In addition, even during normal operation, if necessary, the bisphenol A product in a molten state can be extracted using this transfer line. That is, if necessary In this way, a bisphenol A granular product and a molten product can be obtained at the same time.

FIG. 1 is a process chart of an example of the method for producing bisphenol A of the present invention. The present invention also provides an apparatus for producing bisphenol A, which can carry out the above-described method for producing bisphenol A.

The apparatus for producing bisphenol A according to the present invention includes a heating and melting apparatus for adducts of bisphenol A and phenol, a phenol removal apparatus, and a granulation apparatus, and a molten state obtained by the phenol removal apparatus. A pipe is provided to transfer bisphenol A out of the granulator.

In one embodiment of the apparatus for producing bisphenol A according to the present invention, a reaction apparatus for condensing phenol and acetone, a low-boiling-point component removing apparatus, a concentrating apparatus, a crystallization-solid-liquid separation apparatus, a heating and melting apparatus, and a dephenol removing apparatus In addition to having an apparatus and a granulating apparatus, a pipe is provided between the outlet of the dephenolic apparatus and the inlet of the concentrating apparatus for returning bisphenol A extracted from the dephenolic apparatus to the concentrating apparatus. Further, in the apparatus of the present invention, if necessary, a pipe for transferring bisphenol A to a production apparatus using bisphenol A as a raw material is provided in a pipe for returning bisphenol A to the concentrating apparatus. be able to.

The apparatus of the present invention can be provided with a mechanism for mixing or dissolving the bisphenol A in a molten state to be transported out of the granulation apparatus into water or an aqueous sodium hydroxide solution, if necessary.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Reference example 1

Bisphenol A was continuously produced according to the process for producing bisphenol A shown in FIG.

A reactor filled with 600 g of cation exchange resin was heated to a temperature of 7600 hrs at a rate of 460 g / hr for phenol, 280 g / hr for acetone, and 16 g / hr for ethyl mercaptan. The solution was continuously supplied while maintaining the temperature at 5 ° C. The reaction mixture was sent to a low-boiling component removal step for removing low-boiling components mainly composed of unreacted acetone, and low-boiling components mainly composed of unreacted acetone were removed. Raw from low boiling point component removal process A reaction product mainly composed of bisphenol A and unreacted phenol was obtained at 464 Og Zhr, and this reaction product was obtained under the conditions of 1650 ° C and 53.3 kPa. It was sent to the maintained concentration step.

In this concentration step, the phenol was partially removed, and the concentration was adjusted so that the concentration of bisphenol A became 30% by weight. Water is added to the bisphenol A concentrated solution in which the concentration of bisphenol A from the concentration step is 30% by weight (the remainder is mostly phenol), and this mixture is sent to the crystallization / solid-liquid separation step. Was done. In the crystallization step, cooling crystallization is performed at 45 ° C, and an adduct of bisphenol A and phenol crystallizes. The slurry solution of the adduct was sent to a solid-liquid separation step and centrifuged to separate an adduct crystal of bisphenol A and phenol and a mother liquor.

Crystallization ・ Adduct crystals of bisphenol A and phenol continuously obtained at 870 g / hr from the solid-liquid separation process are sent to the adduct heating and melting process and heated and melted at a temperature of 170 ° C. I let it. Next, the heat-melted adduct crystal of bisphenol A and phenol is sent to a process maintained at 170 ° C. and 5.3 kPa, and most of the phenol is added. Was distilled out to obtain bisphenol A in a molten state. Next, the residual bisphenol A is substantially completely removed by further steam stripping the molten bisphenol A from which most of the phenol has been distilled off, and the bisphenol A in the molten state is removed. Obtained continuously at g / hr.

The thus obtained bisphenol A in a molten state is sent to the granulation step, where the bisphenol A in a molten state dropped in a droplet form from the top of the granulation tower is brought into contact with cooling nitrogen gas in an alternating current. Granules of bisphenol A were continuously obtained at 538 g Z hr.

Example 1

In Reference Example 1, a trouble occurred in the granulation process, and it was not possible to send the bisphenol A in the molten state from the phenol removal process to the granulation process. An intervening return line continuously returns the entire amount of bisphenol A in the molten state (545 g / hr) to the enrichment process, stops supplying acetone in the reaction process, and allows only phenol to flow. Continued I did.

Five hours later, the trap in the granulation process was resolved, so the return to the concentration process was stopped, bisphenol A in a molten state was supplied to the granulation process, and acetone was supplied to the reaction process. A granulated product of bisphenol A was produced.

Example 2

In Reference Example 1, a trouble occurred in the granulation process and the processing capacity in the granulation process was reduced by half, so half of the bisphenol A in the molten state from the phenol removal process was sent to the granulation process and the remaining Half the amount of bisphenol A in the molten state was sent to the concentration step through the return line in the same manner as in Example 1. Along with this, in the reaction process, the reaction was continued with the supply of acetone being reduced by half to 140 g / hr.

Comparative Example 1

In Reference Example 1, clogging occurred in the granulation process, and the melted bisphenol A from the phenol removal process could not be sent to the granulation process. A was drawn into the slop tank, and the supply of acetone was stopped in the reaction process, and only phenol was kept flowing. Six hours later, the clogging of the granulation process was cleared, and the supply of acetone was resumed. Twenty-two hours later, the granulation process returned to the normal operation in which granulated bisphenol A was produced. Industrial applicability

According to the method for producing bisphenol A of the present invention, a molten product and a granular product of bisphenol A can be produced at the same time, and at the time of abnormality such as a trouble in the granulation process, the operation of equipment other than the granulation system can be performed. It is not necessary to stop, and the bisphenol A generated when the granulation system is stopped can be effectively used without waste, and the time required for steady operation when the granulation system is restarted can be reduced.

Claims

The scope of the claims

(1) An adduct of bisphenol A and phenol is heated and melted in a heating and melting step, and the resulting liquid mixture is dephenolized in a dephenol step to obtain a molten bisphenol A, In the method for producing bisphenol A by granulation in the granulation step in the next step, at least a part of the bisphenol A in the molten state obtained in the phenol removal step according to the processing capacity in the granulation step Is transferred to the outside of the granulation step.

(2) An adduct of bisphenol A and phenol is used to obtain a reaction mixture containing bisphenol A by a reaction step of condensing phenol and acetone, and then a low-boiling component removing step, a concentration step, 2. The method for producing bisphenol A according to claim 1, which is obtained by sequentially performing a precipitation / solid-liquid separation step.

3 After obtaining a reaction mixture containing bisphenol A by a reaction step of condensing phenol and acetone, the reaction mixture is subjected to a low-boiling-point component removal step, a concentration step, a crystallization-solid-liquid separation step, a heat-melting step, In the method of producing bisphenol A by sequentially performing the phenol process and the granulation process, at least a part of the bisphenol A extracted from the dephenol process is returned to the concentration process according to the processing capacity in the granulation process. A process for producing bisphenol A.

4 In the bisphenol A production equipment that has a heating and melting device for adducts of bisphenol A and phenol, a dephenol device and a granulation device, the molten bisphenol A obtained by the dephenol device is granulated. Bisphenol A production equipment characterized by having a pipe for transporting it outside.

(5) Bisphenol A manufacturing equipment, which has a reaction device for condensing phenol and acetone, a low-boiling component removing device, a concentration device, a crystallization / solid-liquid separation device, a heating and melting device, a dephenol device, and a granulation device Outlet of the above dephenol unit Characterized in that a pipe for returning bisphenol A extracted from the dephenolizer to the concentrator is provided between the feeder and the inlet of the concentrator.

6. The method for producing bisphenol A according to claim 3, wherein the amount of acetone introduced into the reaction step is adjusted according to the amount of bisphenol A returned to the concentration step.

7. The process for producing bisphenol A according to claim 1, wherein the bisphenol A in a molten state to be transported out of the granulation step is mixed or dissolved in water or an aqueous solution of sodium hydroxide.

(8) At the time of occurrence of a trouble in the granulation step, at least a part of the bisphenol A in a molten state obtained in the dephenol removal step is transferred to another manufacturing apparatus using the bisphenol A as a raw material. 7. The method for producing bisphenol A according to 7.

9 Return at least a part of the bisphenol A extracted from the dephenol removal step to the concentration step, and transfer at least a part of the remaining bisphenol A to another manufacturing apparatus that uses the bisphenol A as a raw material. The method for producing bisphenol A according to claim 3, wherein:

10. The method for producing bisphenol A according to claim 8 or 9, wherein the other production apparatus using bisphenol A as a production raw material is a polycarbonate production apparatus or an epoxy resin production apparatus.

1 1 A mechanism for mixing or dissolving the bisphenol A in the molten state to be transported out of the granulator with water or sodium hydroxide aqueous solution, together with the piping for transporting the bisphenol A in the molten state outside the granulator. 5. The apparatus for producing bisphenol A according to claim 4, further comprising: