JPH0417170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides improved 2,2-bis(4-hydroxyphenyl)propane, bisphenol A.
The present invention relates to a method for manufacturing.

Bisphenol A is usually produced from phenol and acetone in the presence of an acidic catalyst. In this production, co-catalysts such as sulfur compounds may be added.

In the conventional production method, bisphenol A is of course produced in high yield, but the produced bisphenol A is its isomer 2-(4-hydroxyphenyl)-2- (2
-Hydroxyphenyl)propane (hereinafter abbreviated as O, P' form), a trinuclear product obtained by reacting bisphenol A with 1 mole of acetone and phenol, and a by-product of 2,2,4-trimethyl-4- It contains (4-hydroxyphenyl)chroman (hereinafter abbreviated as codimer), etc., and has a purity problem when used as a raw material for polycarbonate, polyester, etc. Therefore, these raw materials are purified by combining various purification methods such as distillation, extraction, recrystallization, and stripping.

Since the higher the reaction temperature, the more impurities are produced, the reaction is carried out at as low a temperature as possible, usually from 35 to 80°C. Therefore, bisphenol A produced during the reaction forms an adduct with phenol and crystallizes, and the heat of crystallization partially increases the reaction heat, even though the reaction is carried out at a very low temperature. However, there is a problem in that large amounts of impurities are produced as by-products. Furthermore, since the crystals formed during the reaction grow rapidly, there is a problem that impurities are incorporated into the crystals. Furthermore, due to rapid nucleation, only fine crystals are formed, and once crystallization begins, the apparent viscosity of the reaction mixture increases, stirring efficiency decreases, and it becomes increasingly difficult to remove the heat of crystallization. This is causing a vicious cycle.

As a method to solve these drawbacks, (1) the reaction is stopped when the conversion rate of acetone is 50 to 80%, that is, before the adduct of bisphenol A and phenol crystallizes, and unreacted acetone is removed under reduced pressure. A method for crystallizing bisphenol A and phenol by removing acetone or by blowing nitrogen gas and cooling the reaction mixture by the heat of vaporization of acetone (Japanese Patent Publication No. 42-26787), (2) O A reaction mixture of bisphenol A containing , P'- isomers is maintained at a temperature lower than the reaction temperature, and O, P'-
A method for obtaining high-purity bisphenol A by converting the body into bisphenol A (Special Publication No. 43-
(Japanese Patent Publication No. 18695), (3) A method of increasing the reaction rate and suppressing the by-product of impurities by using a cocatalyst (Japanese Patent Publication No. 18695), (4) First conducting a small amount of reaction to produce bisphenol. There is a method (German Patent No. 1168445) in which a mixture of phenol and acetone is gradually added together with hydrogen chloride to carry out the reaction once crystals of A and phenol have started to crystallize.

However, in method (1), it is necessary to stop the reaction when the conversion rate of acetone is 50 to 80%, resulting in poor bisphenol A productivity and the problem that acetone must be recovered. In method (2), O, P'-isomers are reduced, but not only do other impurities such as trinuclear bodies and codimers remain as they are, but also O, P'-isomers are reduced by bisphenol. It takes time to convert to A. In method (3), a sulfur compound with a foul odor is used as a cocatalyst, which not only poses problems in handling, but also has the disadvantage that the sulfur compound must be removed from the bisphenol A obtained. be. In addition, in method (4), it is necessary to first react a small amount to crystallize the crystals, and then gradually add the raw materials, which has the disadvantage of taking extra time.Even with a small amount of reaction, impurities are generated as by-products. There is a problem with doing so.

As seen above, the reality is that there is no industrially satisfactory method for producing bisphenol A.

As a result of intensive study on an improvement method for the production of bisphenol A, the present inventors discovered that by reacting phenol and acetone in the presence of an acidic catalyst, the bisphenol A produced before and after becoming saturated in the reaction mixture When a very small amount of crystals of phenol A or the adduct of bisphenol A and phenol is added, there is no sudden heat generation due to rapid crystallization of the adduct of bisphenol A and phenol, and there is no increase in the apparent viscosity of the reaction mixture. Furthermore, they discovered that the formation of impurities in the reaction mixture obtained after the reaction is completed, and after further research, they finally completed the present invention.

That is, the present invention uses phenol, acetone and/or
Or, in a method for producing bisphenol A by reacting paraisopropenylphenols in the presence of an acidic catalyst, the concentration of bisphenol produced by the reaction in the reaction mixture is 50% of the saturation concentration.
From the time when the adduct of bisphenol A and phenol produced begins to crystallize, crystals of bisphenol A and/or crystals of the adduct of bisphenol A and phenol are added to the reaction mixture. Bisphenol A characterized by
This is a manufacturing method.

The paraisopropenylphenols used in the present invention include 2-(4-hydroxyphenyl)-2-propanol, 4-isopropenylphenol, and
- Contains linear oligomers of isopropenylphenol.

Examples of the acidic catalyst used in the present invention include inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, and phosphoric acid, organic sulfonic acids such as toluenesulfonic acid and phenylsulfonic acid, and solid acids represented by cation exchange resins. can. Among them, hydrochloric acid is preferred because it causes fewer side reactions and is easy to remove.

Bisphenol A can be produced by any conventional method except for adding crystals of bisphenol A or an adduct of bisphenol A and phenol during the reaction.

That is, 2 to 12 phenols per mole of acetone.
mol, preferably 3 to 10 mol, more preferably 4
~7 mol in the presence of an acidic catalyst such as sulfuric acid, hydrochloric acid, H-type cation exchange resin, etc. at 30-85°C, preferably
The reaction is carried out at 35-60°C with stirring. As the reaction progresses, heat is generated, so the reaction temperature is adjusted to within the above range by cooling from the outside.

As the reaction progresses, bisphenol A is produced,
Halfway through, bisphenol A reaches saturation. The time to reach this saturation varies depending on the molar ratio of the raw materials and the reaction temperature, but for example, when the molar ratio of phenol and acetone is 7 and the reaction temperature is 40°C, it takes 1.7 hours, and when the molar ratio is 6 and the reaction temperature When is 55℃
It takes about 2.1 hours.

If the reaction mixture in which bisphenol A reaches saturation is further reacted, the molar ratio of the raw materials will also change.
Although it varies depending on the reaction temperature, an adduct of bisphenol A and phenol rapidly crystallizes in 20 minutes to 2 hours after bisphenol A reaches saturation, and the reaction temperature rises rapidly. For this reason, in the past, many impurities were produced.

In the present invention, it is preferable to start from the time when the concentration of bisphenol A in the reaction mixture reaches 50% of the saturation concentration until the crystals of the adduct of bisphenol A and phenol that are produced start to crystallize. Between the time when the concentration of bisphenol A reaches 80% of the saturation concentration and the time when the concentration of bisphenol A becomes slightly supersaturated, crystals of bisphenol A and/or phenol adducts of bisphenol A are formed. The reaction is continued by adding the crystals as a fine powder or as a slurry dispersed in phenol, water, an organic solvent, etc.

If the crystals are added while the concentration of bisphenol A is less than 50% of the saturated concentration, the added crystals will dissolve and the crystals will have no effect. Furthermore, the object of the present invention can be achieved by increasing the amount of crystals added, but in that case most of the added crystals will be dissolved by the time the effect appears, and the bisphenol in the reaction mixture will be substantially reduced. The concentration of A is 50% or more of the saturation concentration. Further, once the adduct of bisphenol A and phenol begins to crystallize, even if crystals are added, heat generation due to crystallization cannot be prevented, and the result is the same as when no crystals are added.

The amount of bisphenol A crystals and/or adduct crystals of bisphenol A and phenol added is 0.0001 to 10% by weight, preferably 0.0005 to 1% by weight, more preferably 0.001% by weight based on the raw material phenol.
~0.1% by weight. When the amount of crystals added is less than 0.0001% by weight, no effect is obtained at all, or even if it is obtained, the effect is small, and even when more than 10% by weight is added, there is almost no difference from when it is less than 10% by weight. This will only lead to a decrease in productivity.

Further, a part of the reaction-completed mixture may be used as the crystals, and in this case, it is preferable to use the crystals so that the amount of the crystals in the mixture is within the above range.

Furthermore, when the crystals are used as a slurry, any of phenol, water, organic solvents, etc. can be used as the solvent, but it is preferable to use phenol as a raw material.

The crystals can be added at once or in several parts within the above period.
Alternatively, it may be added continuously.

In addition, in the present invention, a part or all of acetone may be replaced with paraisopropenylphenols. In this case, the reaction will be faster than when acetone is used.

If bisphenol A or crystals of adducts of bisphenol A and phenol are added during the reaction, the bisphenol A produced by the reaction will crystallize very gradually using the added crystals as nuclei, resulting in the generation of heat of crystallization. The heat generated is also very gradual and can be removed very easily. In addition, the purity of the crystal increases,
Since the grain size of the crystals also improves, the apparent viscosity of the reaction mixture does not become so high that stirring can be performed easily, and impurities are concentrated in the liquid part of the reaction mixture, and the impurities are converted to bisphenol A through an equilibrium reaction.
, there is no accumulation of impurities in the entire reaction system, resulting in an extremely favorable reaction.

Therefore, by isolating bisphenol A from the reaction mixture thus obtained according to the conventional method for isolating bisphenol A, highly pure bisphenol A can be obtained very easily. .

The present invention will be further explained below with reference to Examples.

Reference example 1 (Saturation time of bisphenol A and crystallization start time of adduct of bisphenol A and phenol)
423 g (4.5 mol) of phenol, 43.5 g (0.75 mol) of acetone, and concentrated hydrochloric acid in a flask with an internal volume of 1.
7.25g was added and the temperature was raised to 45℃. Next, hydrogen chloride gas was blown into the mixture while stirring to start the reaction. Thereafter, stirring was continued, and crystals were generated 2 hours and 20 minutes after the start of the reaction. After 8 hours, the reaction was completed, and the liquid portion of the slurry of the reaction mixture was separated, and the concentration of bisphenol A in this was measured, and it was approximately 11% by weight.
It was hot.

On the other hand, after starting the reaction, take a portion of the reaction mixture and
As a result of measuring the concentration of bisphenol A therein, it was found that it reached 11% by weight after 1 hour and 25 minutes, that is, 55 minutes before the bisphenol A and phenol adduct crystals began to crystallize. That is, bisphenol A
was saturated approximately 1 hour and 25 minutes after the start of the reaction.

Reference Example 2 (Saturation time and crystallization start time when using paraisopropenylphenols) In Reference Example 1, 8.7 g (0.15 mol) of acetone
The reaction was carried out in the same manner as in Reference Example 1, except that 14.1 g (0.15 mol) of phenol was replaced with 20.1 g of a linear dimer of paraisopropenylphenol.

Crystals began to precipitate 1 hour and 45 minutes after the start of the reaction.
Further, the reaction was stopped 8 hours after the start of the reaction, and the concentration of acetone in the slurry of the reaction mixture was examined, and it was found to be undetectable, and the concentration of bisphenol A in the solution portion was approximately 11% by weight.

On the other hand, after starting the reaction, take a portion of the reaction mixture and
When the concentration of bisphenol A was measured, it was found that the concentration of bisphenol A reached 11% by weight after 55 minutes, that is, 50 minutes before the start of crystallization. That is, bisphenol A was saturated 55 minutes after the start of the reaction.

Example 1 Phenol was placed in a reactor with an internal volume of 1.2 m ³ equipped with a jacket and a stirrer and whose inner wall was lined with glass.
846 kg (9000 mol), acetone 87 kg (1500 mol), and 14.5 kg of concentrated hydrochloric acid were charged, hydrogen chloride gas was blown into the reactor, and the reaction was started with stirring. The temperature of the reaction was maintained at 45°C by passing 45°C water through the jacket. When 30 g of crystals of the adduct of bisphenol A and phenol were added to the reaction mixture 1 hour and 25 minutes after the start of the reaction, crystals of the adduct of bisphenol A and phenol were rapidly and gently generated.
At the same time, the temperature of the reaction mixture rose slightly.46
℃, but then returned to 45℃ in 28 minutes.
The reaction was further continued and stopped 8 hours after the start of the reaction.

Analysis of the slurry of this reaction mixture revealed that
Trinuclear bodies are almost undetectable, and O, P′ monomers, and codimers are respectively detected for bisphenol A.
It was 1.5 and 0.44% by weight.

Furthermore, the crystals in the slurry were quite large, and the slurry could be stirred extremely smoothly.

Thereafter, high purity bisphenol A was obtained by isolation using a conventional method.

Example 2 A reaction was carried out in the same manner as in Example 1, except that bisphenol A crystals were used instead of bisphenol A and phenol adduct crystals.

After the addition of the crystals, new crystals of the adduct of bisphenol A and phenol formed rapidly and gently. At the same time, the temperature of the reaction mixture rose to a maximum of 48°C. After that, it took 47 minutes for the temperature to return to 45°C.

When the reaction was stopped 8 hours after the start of the reaction and the slurry of the reaction mixture was analyzed, trinuclear bodies were not detected, and O, P′-isomers and codimers were bisphenol A.
They were 1.6 and 0.48% by weight, respectively.

Comparative Example 1 Example 1 except that the crystals of the adduct of bisphenol A and phenol were not added.
The reaction was carried out in the same manner.

Crystals were generated 2 hours and 35 minutes after the start of the reaction, and at the same time the temperature of the reaction mixture rapidly rose to 52°C. 1 for the temperature of the reaction mixture slurry to return to 45℃
It took 25 minutes.

The reaction was stopped 8 hours after the start of the reaction, and the reaction mixture slurry was analyzed to find that the O, P-form was 1.8% by weight and the codimer was 0.80% by weight based on bisphenol A.

Furthermore, the crystals in the slurry were quite fine and were difficult to isolate compared to Examples 1 and 2. Stirring the slurry was also quite difficult.

Example 3 In Example 1, except that 100 g of the reaction mixture slurry obtained in Example 1 (approximately 30 g as crystals of the adduct of bisphenol A and phenol) was used instead of the crystal of the adduct of bisphenol A and phenol. was reacted in the same manner as in Example 1.

The results were exactly the same as in Example 1.

Example 4 In Example 1, instead of 28.2 kg of part of the phenol and 17.4 kg of acetone (300 mol each), 40.2 kg of para-isopropenyl phenol mixture (main component linear dimer) (as para-isopropenyl phenol) was used. The reaction was carried out in the same manner as in Example 1 except that 300 mol) was used.

When phenol adduct crystals of bisphenol A were added 55 minutes after the start of the reaction, new crystals were rapidly and gently generated. At the same time, the temperature of the reaction mixture rose to 46.5°C. After 39 minutes, the temperature returned to 45℃.

When the reaction was stopped 8 hours after the start of the reaction and the reaction mixture was analyzed, trimers and paraisopropenyl phenols were not detected, and O, P'-isomers and codimers were 1.5 and 1.5, respectively, relative to bisphenol A.
It was 0.45% by weight.

Comparative Example 2 The reaction was carried out in the same manner as in Example 4, except that the crystals of the adduct of bisphenol A and phenol were not added.

Crystals began to form 1 hour and 50 minutes after the start of the reaction, and at the same time the temperature of the reaction mixture rose to 51°C.
It took 1 hour and 20 minutes for the temperature to return to 45°C.

When the reaction was stopped 8 hours after the start of the reaction and the reaction mixture slurry was analyzed, the O, P'-form and codimer were 1.6 and 1.6, respectively, relative to bisphenol A.
It was 0.65% by weight.

Claims (1)

[Scope of Claims] 1. In a method for producing bisphenol A by reacting phenol with acetone and/or paraisopropenyl phenols in the presence of an acidic catalyst, bisphenol A produced by the reaction is produced in a reaction mixture. Between the time when the concentration reaches 50% of the saturation concentration and the time when the adduct of bisphenol A and phenol starts to crystallize, crystals of bisphenol A and/or crystals of an adduct of bisphenol A and phenol are formed. A method for producing bisphenol A, which comprises adding to a reaction mixture. 2. Production of bisphenol A according to claim 1, wherein crystals of bisphenol A and/or crystals of an adduct of bisphenol A and phenol added to the reaction mixture are dispersed in a solvent to form a slurry. Method. 3 Claim 2 in which the solvent is phenol
A method for producing bisphenol A as described in . 4. The method for producing bisphenol A according to claim 2, wherein a slurry of crystals of an adduct of bisphenol A and phenol is part of the reaction completed mixture.