JPH089561B2 - Blocking prevention method in bisphenol A manufacturing process - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preventing clogging in a 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A) production process.

More specifically, it relates to a method for preventing clogging of a condenser when liquefying phenol which is distilled from the top of a distillation column for removing phenol from an adduct of bisphenol A and phenol with a condenser.

[Conventional technology]

Bisphenol A is prepared from acetone and excess phenol in the presence of an acidic catalyst, in some cases with the addition of cocatalysts such as sulfur compounds. In addition to bisphenol A, the reaction mixture includes catalyst, unreacted acetone, unreacted phenol, water of reaction and other reaction byproducts.

The main component of the by-product is 2- (2-hydroxyphenyl) -2- (4-hydroxyphenyl) propane (hereinafter O, P ′ form), and other dianine compounds, trisphenol, polyphenol, and preferably It contains substances that deteriorate the performance of resins obtained by using bisphenol A as a raw material, such as uncolored substances.

One of the methods for recovering bisphenol A from a reaction mixture is to remove the catalyst, water and a small amount of phenol from the reaction mixture, and then cool the remaining liquid mixture to crystallize bisphenol A as an adduct with phenol. The crystals are separated from the mother liquor containing reaction by-products, and phenol is removed from the adduct to recover bisphenol A.

Various methods such as distillation, extraction, and stripping with steam have been proposed as methods for removing phenol from the adduct of bisphenol A and phenol. For example,
52-42790 discloses a method in which the adduct is vaporized at a temperature above 180 ° C. and a reduced pressure for 0.1 to 30 minutes, and bisphenol A is obtained by fractional condensation.

Further, Japanese Patent Publication No. 36-23335 discloses a method in which a solvent having a boiling point of 50 ° C. or higher is used to heat the adduct to 50 ° C. or higher and only the phenol portion is taken out into the solvent.

The method by distillation is generally used because the apparatus is simple and can be carried out without using other solvent or water.
For example, Japanese Patent Publication No. 56-13700 discloses that phenol is distilled off under reduced pressure, decomposable low-boiling components are removed by a pre-distillation removal column, and then bisphenol A is obtained by distillation. Furthermore, after removing the phenol under reduced pressure,
Aliphatic dicarboxylic acid esters (Japanese Patent Publication No. 59-5619), glycols (Japanese Patent Publication No. 61-94), propylene glycol, epoxy resins, etc. (Japanese Patent Publication No. 56-1297).
Japanese Patent Application Laid-Open (Kokai) Publication (KOKAI) Publication No. JP-A-2003-96240, a method of distilling bisphenol A in the presence of a stabilizer is shown.

In the method for obtaining phenol from the top of a tower by distillation of an adduct of bisphenol A and phenol and bisphenol A from the bottom of the tower, when liquefying phenol distilled from the top using a condenser, cooling water is heated to a certain temperature or higher. Need to keep.

However, since 1 to 5% by weight of bisphenol A is contained in the phenol distilled off from the top of the column, there is a problem that the bisphenol A is solidified in the condenser and adheres to the tube surface, and finally clogs.

[Problems to be Solved by the Invention]

An object of the present invention is to liquefy phenol, which is distilled from the top of a distillation column for removing phenol from an adduct of bisphenol A and phenol, with a condenser,
It is an object of the present invention to provide a method for preventing blockage of the condenser.

[Means for solving the problem]

The present inventors have conducted diligent studies to achieve the above object, distilling phenol from the top of the distillation column and liquefying it in a condenser, and a part of the condenser distillate is removed from the upper part of the condenser. It was found that by spraying, it is possible to prevent the condenser from being blocked,
The present invention has been completed.

That is, the present invention provides a process for producing 2,2-bis (4-hydroxyphenyl) propane by removing phenol from an adduct of 2,2-bis (4-hydroxyphenyl) propane and phenol. 2,2-bis (4-
A bisphenol characterized by using a distillation column to obtain (hydroxyphenyl) propane, distilling phenol from the top of the column, and liquefying it in a condenser, by spraying a part of the condenser distillate from the upper part of the condenser. A method for preventing blockage in the manufacturing process.

The adduct of phenol and bisphenol A in the present invention may be obtained directly from the reaction mixture, or may be an adduct crystal obtained by concentrating a crystallization filtrate obtained by removing the adduct from the reaction mixture. It may be. Crystals obtained by mixing and recrystallizing crude bisphenol A and phenol may be used, for example, from a reaction product obtained by condensing phenol and acetone in the presence of a hydrochloric acid catalyst, hydrochloric acid, water and a small amount of phenol. It can be obtained by cooling after distilling off. It can also be obtained by directly cooling the effluent of the cation exchange resin from the fixed bed reactor. Further, as seen in JP-A-51-61240, it is possible to crystallize the adduct by adding water to a mixture of bisphenol A and phenol and cooling.

In the present invention, the distillation column for removing phenol may be of any type such as a packed column or a plate column, the liquid temperature in the distillation column is in the range of 160 to 200 ° C., and the operating pressure is 10 It is preferable to operate in the range of -100 Torr.

As the condenser for liquefying the phenol distilled off from the top of the distillation column used in the present invention, any type can be used as long as it is a vertical condenser. A vertical multitubular condenser is preferably used, in which phenol in a tube and cooling water on the shell side are suitable.

The cooling water passing through the condenser preferably has an outlet temperature of 42 to 45 ° C., which is close to the freezing point of phenol, for good efficiency.

A feature of the present invention is that a part of the condenser distillate is sprayed from the upper portion of the condenser. By spraying this condenser distillate, it is possible to prevent bisphenol A contained in phenol distilled from the top of the distillation column from solidifying in the condenser, and prevent clogging.
The temperature of the sprayed phenol liquid is preferably at least above the freezing point. At a temperature below the freezing point, there is a risk that the phenol will begin to solidify and the condenser will be clogged, and if the temperature is too high, the cooling efficiency will deteriorate.

The spray amount of the distillate varies depending on the structure of the condenser, but is usually preferably about 5 to 20% of the distillate. If the application amount is small, the blockage prevention is not complete, and if the application amount is too large, it is necessary to enlarge the device and only increase the cost.

 The method of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram showing one mode of a method for preventing clogging of a condenser according to the method of the present invention.

In the method of the present invention, the molten adduct 1 of an adduct of bisphenol A and phenol is sent to a distillation column 2 (dephenolization column), phenol 3 is distilled off from the top of the column, and bisphenol A4 containing a small amount of phenol from the bottom of the column. Is obtained.

The phenol 3 distilled from the top of the tower is cooled and liquefied by the condenser 5 and is temporarily stored in the receiver 6. This distillate 7
According to the present invention, a part of the above is dispersed and circulated from the upper part of the condenser 5, and the remaining part is extracted and sent to the next step.

〔Example〕

Hereinafter, the method of the present invention will be specifically described with reference to Examples and Comparative Examples.

Example 1 In FIG. 1, the adduct was heated at 120 ° C., the molten adduct 1 obtained was fed to the distillation column 2 at 10,000 kg / hr, and 15 Tor
Distilled under the conditions of r, 170 ℃, Phenol 3 is about 3000kg / hr
Distilled in. In addition, bisphenol extracted from the bottom of the tower
A4 was about 7,000 kg / hr.

The distilled phenol 3 was supplied to the condenser 5 (vertical multitubular type), and the distillate 7 was sprayed at 300 kg / hr from the upper portion of the condenser 5 using a spray nozzle.

No blockage of the condenser 5 was observed, and stable operation was possible for one year.

Comparative Example 1 Distillate 7 from the top of condenser 5 in Example 1
The same procedure was performed except that the spraying was not performed. As a result, the condenser 5 was blocked once every 5 to 10 days.

〔The invention's effect〕

Since the present invention has the above-mentioned constitution, it becomes possible to prevent clogging of the condenser that liquefies the phenol distilled from the adduct of bisphenol A and phenol, and to operate the condenser continuously for a long period of time. It is a great contribution to the industry.

[Brief description of drawings]

FIG. 1 is a system diagram showing one mode of a method for preventing clogging of a condenser according to the method of the present invention. The reference numerals in the figure are as follows. 1: Melt adduct 2: Distillation tower (dephenolization tower) 3: Phenol, 4: Bisphenol A 5: Condenser, 6: Receiver 7: Distillate, 8: Cooling water 9: Vacuum device, 10: Pump

Claims (1)

[Claims] 1. A process for producing 2,2-bis (4-hydroxyphenyl) propane by removing phenol from an adduct of 2,2-bis (4-hydroxyphenyl) propane and phenol, wherein the adduct is obtained. When a phenol is removed from the product to obtain 2,2-bis (4-hydroxyphenyl) propane, a distillation column is used,
Bisphenol A characterized in that, when phenol is distilled off from the top of the tower and liquefied in a condenser, a part of the condenser distillate is sprinkled from the top of the condenser
Blockage prevention method in manufacturing process.