JPS5821633A - Preparation of bisphenol a - Google Patents

Abstract

PURPOSE:To obtain the titled compound, by precipitating bisphenol A from a reaction mixture of acetone and phenol, adsorbing the separated filtrate on a specific adsorbent, washing the adsorbent with a specified cleaner periodically, recycling it to the reaction system. CONSTITUTION:Acetone is reacted with phenol in the presence of a catalyst of strongly acidic cation exchange resin, to give a reaction mixture, which is cooled, so that bisphenol (BPA for short) is precipitated as crystal of an addition product of BPA with phenol, filtered and separated. The separated mother liquor is brought into contact with an adsorbent of silica-alunina so that a coloring component is adsorbed and removed. The adsorbent having adsorbed the coloring component is periodically washed by passing a silica-alumina mixture through it, the coloring component is desorbed, and the adsorbent is recycled to the reaction system. EFFECT:The coloring component in the filtrate is removed efficiently, and the adsorbent is regenerated well. USE:A raw material for polycarbonate resin, epoxy resin, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing bisphenol A.

Bisphenol A (hereinafter abbreviated as BPA) is useful as a raw material for polycarbonate resins, epoxy resins, etc., and its production method involves combining acetone with an excess amount of phenol and a strongly acidic cation exchange resin (hereinafter referred to as K-RI).
A method is known in which the reaction is carried out in the presence of a catalyst (referred to as IIC).

In this reaction, in addition to BPA, a BPA isomer in which phenol and acetone are bonded at positions other than the para position is produced as a by-product, so the resulting reaction mixture is mainly composed of BPA, BPA isomers, and phenol. From this reaction mixture, BP
To recover A, first, BPA is precipitated as BPA-phenol adduct crystals by cooling or concentrating the reaction mixture, and the precipitated crystals are separated and then thermally decomposed into phenol and BPA to convert BPA into BPA.
can be obtained. The mother liquor after separating the crystals of the BPA/phenol adduct from the reaction mixture contains BPA isomers and phenol. Partly BPA
Since phenol can be reused as a raw material, it is desirable to recycle the separated mother liquor to the reaction system of phenol and acetone.

However, the mother liquor contains coloring components whose structure is unknown as a by-product of the reaction. When recycled into the reaction system, colored components accumulate in the reaction system, resulting in an increase in the degree of coloration of the BPA product.

One possible way to avoid this is to subject the recycled mother liquor to adsorption and decolorization using an appropriate method.

In this case, industrially, it is necessary not only to select an adsorbent with excellent adsorption effect, but also to use an excellent cleaning solution to desorb colored components from the treated adsorbent and regenerate the adsorbent.

In view of the above circumstances, the present inventors separated and recovered BPA from the reaction mixture of phenol and acetone as crystals of BPA/phenol adduct, and then treated the r liquid with an adsorbent,
As a result of various studies on methods for efficiently removing colored components in r-liquid and regenerating the adsorbent, we found that we used a certain adsorbent, and furthermore, we decided to use a certain adsorbent after treatment. The present invention was completed based on the discovery that this objective can be achieved by cleaning with a cleaning solution.

That is, the gist of the present invention is to precipitate and separate BPA as crystals of a BPA/phenol adduct from a reaction mixture obtained by reacting acetone and phenol in the presence of a -RIB catalyst, and to separate the separated mother liquor from the reaction mixture. A method for producing BPA for recycling into a system, characterized in that the mother liquor is brought into contact with a silica-alumina adsorbent, and the adsorbent is periodically washed with a water-phenol mixture.
It consists in the manufacturing method of PA.

The present invention will be explained in detail below.

The method for producing BPA that is the object of the present invention is to use acetone and phenol in an excess amount of 6 to 12 moles relative to the acetone, substantially without using a solvent as a third component.
A method of reacting in the presence of a catalyst consisting of -R-E is exemplified.

This reaction is usually carried out at a temperature of 0 to 120 °C, preferably at a pressure of from normal pressure to 1 K9/d G! ; carried out at a temperature of 0-100°C. If the reaction temperature is too low, the reaction activity of the catalyst will not be sufficiently exhibited, and if it is too high, a large amount of by-products will be produced, which is not preferable. The reaction time varies depending on the reaction type, but for example, in the case of a batch reaction using a stirred tank type reactor, the reaction time is usually 0. /-20 hours, and in the case of a piston flow type continuous reaction with a fixed bed of catalyst, the space velocity (S, V) is 0. /-ko0
ksr-'.

4. In the present invention, since the presence of water in the reaction system is not preferable, the water concentration in the reaction system is usually 7% by weight or less, preferably 0, S or less by weight.

Examples of -RIIIX used as a catalyst include cloth plate sulfonic acid type cation exchange resins, which are usually gel type or porous type and have a degree of crosslinking of, for example, 2 to 1-. Further, these K-RIFi may have, for example, a part of the sulfonic acid group modified with mercaptans or the like.

After the reaction is completed, the mixture is subjected to pretreatment such as filtration as necessary, and then the BPA is removed by cooling the reaction solution to, for example, below go,'c, preferably to qs-daO''C.
It is precipitated as crystals of PA/phenol adduct. If the cooling temperature in this crystallization step is too low, the phenol will solidify, which is not preferable. In this crystallization, only the crystals of the BPA/phenol adduct are precipitated, and the BPA isomers are dissolved in the phenol without being precipitated.

The mixture after crystallization contains crystals of BPA/phenol adduct.
The crystals are usually distilled using a thin film evaporator or the like at a temperature of tbo℃ or higher to produce BP.
It can be decomposed into three parts, A and phenol, and each can be recovered.

On the other hand, since the mother liquor from which the BPA/phenol adduct crystals are separated contains BPA isomers, this mother liquor is subjected to an isomerization reaction as necessary, and then added to the reaction system of phenol and acetone. However, the present invention requires that the r-liquid be treated with a silica-alumina adsorbent before being recycled.

The silica-alumina that can be used in the present invention includes, for example, 10-1IO weight percent of alumina based on 10 weight parts of silica. Generally, as a catalyst, pellets in the form of cloth plates or pulverized ones can be used, but in order to increase the adsorption efficiency, for example, 10 mesh or less is preferable.

The contact treatment between FiI and the adsorbent is usually carried out by passing the f liquid through a packed bed filled with the adsorbent. The treatment temperature is usually 1IO-120°C, preferably bo-qo
°C, and the contact time is typically space velocity (s, v
) is adjusted to approximately / ~ / Ohr”.

The colored components contained in the r-liquid are efficiently adsorbed and removed by the above-mentioned contact treatment with silica-alumina, but the silica-alumina that has absorbed the colored components needs to be periodically washed to desorb the colored components. There is.

The present invention requires that silica-alumina be washed with a water-phenol mixture. The mixing ratio of water and phenol is usually 5 to 100 parts by weight, preferably 20 to 100 parts by weight of phenol.
If the amount of water is too large or too small, colored components cannot be removed better than silica-aluminum or silica. The cleaning process is usually carried out by passing a water-phenol mixture through a packed bed of silica-alumina. The temperature during cleaning is usually between da θ and io.
0C, preferably 60 to 90C.

The cleaning operation is carried out periodically, and the R liquid is brought into contact with the silica-alumina for a certain period of time, and is carried out when a predetermined amount of colored components have been adsorbed.

This periodic cleaning treatment allows the silica-alumina adsorption treatment to be carried out stably for a long period of time.

In the present invention, the contact treatment between the r-liquid and silica-alumina may be carried out after the crystals of the BPA/phenol adduct are separated from the reaction mixture and before the r-liquid is recycled to the reactor. For example, when the r-liquid is brought into contact with a -R"IE catalyst to isomerize a portion of the BPA isomers in the r-liquid to BPA and then recycled to the reaction system, contact treatment with silica-alumina is necessary. can be used before or after the isomerization reaction.

According to the present invention, the colored components in the r-liquid can be efficiently adsorbed and removed, and the adsorbent that has adsorbed the colored components can also be easily regenerated, which is extremely preferable from an industrial perspective. .

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Example A sulfonic acid type cation exchange resin (manufactured by Mitsubishi Chemical Industries, Ltd., trade name Diaion 5K-1011) Iof was packed in a fixed bed reactor equipped with a temperature controller, and the molar ratio of phenol:acetone was 70:l. A mixed solution of is heated to a temperature of 7θ°C with a space velocity (S.

(2)) was passed for 2 hr-' to carry out the reaction continuously.

After the reaction, a part of the phenol in the mixture was evaporated under reduced pressure, and then the mixture was cooled to a temperature of 15°C to precipitate crystals of BPA/phenol adduct. , Otwt, BPA isomer, 9
An r solution containing 4 wt% was collected.

The above R liquid was placed in a packed bed (/, 2Ysl x 30an) filled with 35ml of the adsorbent shown in Table 1 at 73°C, B, V =
The liquid passage treatment was carried out under the conditions of Q, and the absorbance of the r liquid before and after the treatment was measured after the SO waiting time.

Table 1 (Note 1) Silica-alumina: JGC ■Commercial product 6% da molded product pulverized to 20~110 mesh Activated carbon: Mitsubishi Chemical Industries ■Cloth board product Diamond Hope-001 High porous resin: Mitsubishi Chemical Industrial ■Ichi Itami Diaion HP20 (Note 2) Absorbance measurement sample/7. ! f as methano-/I/2! r t
This solution was further diluted twice with methanol, and the absorbance of the solution was measured.

The cleaning solution shown in Table 2 was passed through the packed bed of adsorbent contaminated with colored components after the above experimental treatment for 1 hour under the same conditions as the R solution, and the absorbance of the cleaning solution was measured.

From the results in Tables 2 and 1, the coloring component in the R liquid is silica.
It is well removed by alumina, and the second
From the results in the table, it can be seen that the colored components adsorbed on the silica-alumina are easily desorbed by the water-phenol mixture.

Therefore, in the present invention, even if the r-liquid is recycled to the reaction system, since the colored components have been removed, the reaction system will not be adversely affected.

Sender: Mitsubishi Chemical Industries, Ltd.

Claims (1)

[Claims] (11) From the reaction mixture obtained by reacting acetone and phenol in the presence of a strongly acidic cation exchange resin catalyst, bisphenol A is precipitated and separated as crystals of bisphenol A/phenol adduct, while the separated mother liquor is reacted. A method for producing bisphenol A that is recycled into a system, which is characterized in that the mother liquor is brought into contact with a silica-alumina adsorbent, and the adsorbent is periodically washed with a water-phenol mixture. Manufacturing method.