JPH10265423A - Production of bisphenol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically obtain bis(cresol) fluorene of high quality that is useful as a raw material for polycarbonate by crystallizing out the product from the reaction mixture between fluorenone and cresol by adding a specific solvent thereto without removal of unreacting cresol. SOLUTION: To the reaction mixture containing bis(cresol)fluorene (BCF) of the formula, is added a 6-12C lower aliphatic hydrocarbon or an aromatic hydrocarbon in an amount of 3-25 pts.wt. per 1 pt.wt. of fluorene to dissolve the mixture at a temperature lower than 100 deg.C. Then, the solution is cooled down to room temperature -0 deg.C to crystallize out BCF crystals. The precipitated BCF is purified through a solid-liquid separation means. The mother liquor after removal of BCF crystals is distilled whereby unreacting cresol can be economically recovered. The cresol can be satisfactorily separated by only simple distillation and recovered without rectification and is reusable as a starting material because of its >=99 wt.% purity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing biscresol fluorene (BCF). BCF is a bisphenol useful as a raw material for polycarbonate, epoxy resin, polyester and the like, and as a storage stabilizer for thermal paper.

[0002]

2. Description of the Related Art Similar to the method for producing 9,9-bis (4-hydroxyphenyl) fluorene, BCF is obtained by a condensation reaction of fluorenone and cresol using hydrochloric acid and a catalyst such as mercaptopropionic acid. Ap
pl. Polum. Sci. , 27 (9), 2389,
1982). As a prior art, Japanese Patent Laid-Open Publication No.
No. 0 publication. Specifically, a method in which a lower aliphatic alcohol is mixed into a reaction mixture to form a homogeneous solution after leaving at least a part of unreacted o-cresol after the reaction, and then water is added to precipitate crystals. It has been known.

In these processes, cresol is usually used in excess of fluorenone in order to improve the yield and suppress side reactions, so that excess cresol is removed from the reaction solution by distillation after the reaction is completed. After that, the desired product is obtained by crystallization using a solvent. However, this method has a problem that a high temperature is required for removing cresol, which causes coloring of the product. In addition, since crystals are precipitated during the removal of cresol and the reaction mixture is solidified in the reaction vessel, there is a problem in industrial production.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for producing high-quality BCF from fluorenone and cresol as raw materials, and in particular, provides a method which is economically advantageous and industrially practicable. The purpose is to:

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and as a result of intensive studies, it has been found that unreacted products are obtained from a reaction mixture obtained by a condensation reaction of fluorenone and cresol in the presence of a catalyst. Without removing cresol, a lower aliphatic hydrocarbon having 6 to 12 carbon atoms or an aromatic hydrocarbon (particularly, benzene, toluene, xylene) or a mixed solvent thereof is added as a solvent to form a homogeneous solution. By cooling and crystallizing, high purity and colorless BCF can be obtained in good yield. Further, unreacted cresol can be recovered by distillation from the mother liquor after separating the crystals, and re-used as a raw material. They found that they could be used and completed the present invention. That is, the present invention
The present invention relates to the following BCF manufacturing method.

[0006] 1. A solvent (preferably without removing unreacted cresol from the obtained reaction mixture without removing unreacted cresol from the reaction mixture containing unreacted cresol obtained by subjecting fluorenone and cresol to a condensation reaction using a catalyst) 6-12 lower aliphatic hydrocarbons or aromatic hydrocarbons or a mixed solvent thereof) by crystallization,
A method for producing biscresol fluorene represented by Structural Formula 1, wherein a crystal of biscresol fluorene is precipitated.

[0007]

Embedded image

[0008] 2. Item 1. The method according to Item 1, wherein cresol is recovered (for example, by distillation) from a mother liquor obtained by separating precipitated crystals of biscresol fluorene and reused as a raw material for a condensation reaction. A method for producing cresol fluorene.

3. A method for recovering cresol, comprising recovering cresol by distillation from a mother liquor obtained by separating crystals of biscresol fluorene precipitated by the method described in the above item 1.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described together with its embodiments.

Condensation reaction between fluorenone and cresol BCF can be produced by subjecting fluorenone and cresol to a condensation reaction in the presence of a catalyst.
As the catalyst, known catalysts, for example, various dehydration reaction catalysts can be used. For example, thiols such as β-mercaptopropionic acid and hydrochloric acid gas, and metal chloride and chlorine gas can be used. As cresol, ortho-cresol, meta-cresol and the like can be used. For example, when ortho-cresol is used, BC
F can be obtained.

The purity of cresol used as a raw material is as follows:
Although not particularly limited, the purity is 95% by weight or more, preferably 9% by weight.
It is preferable to use one having 9% by weight or more. Normally, by using an excess of cresol relative to fluorenone (specifically, 2 to 6 parts by weight per 1 part by weight of fluorenone), biscresol fluorene is produced with a high yield and side reactions are suppressed. be able to. Usually, the reaction mixture after completion of the reaction contains B, which is a reaction product,
In addition to CF, unreacted fluorenone, unreacted cresol, catalyst, by-products and the like are contained.

Crystal removal of BCF Crystals of BCF can be removed by removing unreacted cresol and the like from the reaction mixture. For example, unreacted cresol can be removed by distilling the reaction mixture. However, there is a problem that the distillation of cresol requires a high temperature, and the heat causes coloring of the BCF of the product. Also, at the stage where about half of the unreacted cresol was removed, BCF crystals began to precipitate, and the distillation residue could not be removed from the reaction vessel.
There are problems with industrial implementation.

In the present invention, a solvent is added directly to the reaction mixture to dissolve it to form a homogeneous solution, and then cooled to precipitate BCF crystals. Therefore, BCF crystals are directly extracted from the reaction mixture. Can be separated. By selecting a solvent that dissolves in the reaction mixture and has low solubility of BCF as the solvent, BCF crystals can be efficiently precipitated and separated. Specifically, carbon number 6 ~
Twelve lower aliphatic hydrocarbons or aromatic hydrocarbons (benzene, toluene, xylene) are suitable solvents for precipitating BCF from the reaction solution because of their low solubility.

The amount of the solvent used depends on the type of the solvent, but it is preferably 3 to 25 parts by weight, more preferably 5 to 15 parts by weight, per part by weight of fluorenone. When the amount of the solvent used is reduced, BCF is dissolved in the reaction solution, so that it does not precipitate, or even if it precipitates, it becomes a crystal of poor purity containing a large amount of unreacted cresol. On the other hand, if the used amount of the solvent is increased, not only the yield is reduced, but also the effective charge amount of the raw materials into the reactor is reduced, and the economic efficiency is deteriorated.

When dissolving the reaction mixture in a solvent, heating can be performed if necessary. As the temperature of the heated solution, a temperature at which the solution is completely dissolved can be appropriately set depending on the type and amount of the solvent used. Increasing the heating temperature makes the reaction mixture easier to dissolve, but there is a problem of coloring. Therefore, it is better to avoid a high temperature of 100 ° C. or more. By cooling the solution obtained by dissolving the reaction mixture in a solvent, BCF crystals can be precipitated and crystallized. The cooling temperature varies depending on the type and amount of the solvent, but is not particularly limited as long as the temperature allows sufficient precipitation of crystals. Usually about 40 ° C to -10 ° C, preferably room temperature to 0 ° C.
° C. If the cooling temperature is too high, the precipitation will be insufficient and the yield will be low. Also, even if the cooling temperature is too low,
Since the temperature decreases, it is not advantageous in view of the labor required for the production.

By separating the precipitated BCF crystals by means of solid-liquid separation, purified BCF can be obtained. As means for solid-liquid separation, filtration, centrifugation, or the like can be employed.

Recovery of cresol from mother liquor When BCF crystals are solid-liquid separated from the reaction mixture solution, a mother liquor containing a solvent, excess cresol, reaction products, catalyst, and water formed is obtained. In the case of industrial implementation, BCF production can be made economically advantageous by recovering excess cresol. By distilling the mother liquor, cresol can be recovered most economically. The distillation is usually performed under reduced pressure.

When the mother liquor is distilled, the remaining catalyst (eg, hydrochloric acid gas), product water, solvent, and cresol are distilled off at their respective boiling points and separated. The reaction product remains in the kettle as a distillation residue. Since the liquids to be distilled each have a sufficient difference in boiling point, the distillation can be sufficiently separated by simple distillation. Therefore, cresol can be efficiently recovered without rectification. The recovered cresol usually has a purity of 99% by weight or more, and there is no problem in the reaction and no influence on the quality of BCF even when reused as a reaction raw material.

[0020]

According to the present invention, BCF crystals can be separated by adding an appropriate solvent to a condensation reaction mixture of fluorenone and cresol, thereby separating BCF crystals. The above problems can be avoided. The present invention is very useful as an industrial manufacturing process.

[0021]

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention. In this example, the purity was analyzed by HPLC, and expressed by area percentage. The yield is (B
It was calculated by (mol number of CF) / (mol number of fluorenone).

Example 1 90 g of 99% fluorenone and o were placed in a 2 L glass vessel equipped with a stirrer, a cooler, a thermometer and a hydrogen chloride gas inlet tube.
-432 g of cresol and 3 ml of β-mercaptopropionic acid were charged and heated and stirred at 50 ° C to completely dissolve fluorenone. The reaction was started by blowing hydrogen chloride gas at 200 ml / min, and the reaction was continued for 4 hours while maintaining the reaction temperature at 50 ° C. After the reaction is completed, 5
L / min was blown for 30 minutes to expel any residual hydrogen chloride gas in the reactor.

To the obtained reaction solution, 540 g of methanol was added, and the mixture was stirred while heating to the reflux temperature of methanol to dissolve the reaction mixture to form a uniform solution. Then, with stirring, 10 ℃
Cooling was carried out to precipitate crystals, and a solid content was taken out by filtration. The obtained solid content is further added at 60 ° C. for 8 hours,
Drying under reduced pressure was performed. The purity of the obtained crude BCF is 96.6.
%, And the yield was 83.3%.

Example 2 Example 1 except that 540 g of n-octane was used as a solvent.
Was performed in the same manner as described above. The purity of the obtained crude BCF is 9
7.1% and the yield was 78.0%.

Example 3 The procedure of Example 1 was repeated except that 900 g of toluene was used as the solvent. The purity of the obtained crude BCF is 97.2.
%, And the yield was 80.5%.

Example 3 Example 1 was repeated except that 630 g of p-xylene was used as the solvent.
Was performed in the same manner as described above. The purity of the obtained crude BCF is 9
6.0% and the yield was 70.9%.

Example 4 815 g of the mother liquor obtained in Example 1 was attached to a 2-L eggplant-shaped flask equipped with a carburetor for blowing nitrogen gas and a thermometer, and a receiver was provided on the Y-type connector. Into a simple distillation apparatus fitted with a cooling pipe, and n-
Hexane was recovered. Next, under reduced pressure of 10 mmHg, o-
Cresol was recovered by distillation. The obtained o-cresol was 231 g, and the purity was 99.1% (gas chromatographic analysis value).

Comparative Example 1 The same procedure as in Example 1 was carried out except that 540 g of methyl isobutyl ketone was used as a solvent. However, no crystals were precipitated even when cooled to 0 ° C.

Comparative Example 2 The same procedure as in Example 1 was carried out except that 540 g of t-butanol was used as the solvent. However, no crystals were precipitated even when cooled to 0 ° C.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C07B 61/00 300 C07B 61/00 300

Claims (5)

[Claims] The present invention is characterized in that crystals of bis-cresol fluorene are precipitated by crystallization using a solvent from a reaction mixture containing unreacted cresol obtained by subjecting fluorenone and cresol to a condensation reaction using a catalyst. A method for producing biscresol fluorene represented by Structural Formula 1. Embedded image 2. A crystallization using a solvent without removing unreacted cresol from a reaction mixture obtained by subjecting fluorenone and cresol to a condensation reaction using a catalyst,
A method for producing biscresol fluorene, comprising depositing biscresol fluorene crystals. 3. The process for producing biscresol fluorene according to claim 1, wherein the solvent is a lower aliphatic hydrocarbon or an aromatic hydrocarbon having 6 to 12 carbon atoms or a mixed solvent thereof. 4. The method according to claim 1, wherein
A process for producing biscresol fluorene, comprising recovering cresol from a mother liquor obtained by separating precipitated crystals of biscresol fluorene and reusing it as a raw material for a condensation reaction. 5. A method for recovering cresol, comprising recovering cresol by distillation from a mother liquor obtained by separating crystals of biscresol fluorene precipitated by the method according to claim 1 or 2.