KR20120139333A - Method for recovering useful ingredient from bisphenol a tar - Google Patents

Abstract

PURPOSE: A collecting method of useful components through co-cracking of phenol tar and bisphenol A tar is provided to economically collect useful components at high recovery rate. CONSTITUTION: A collecting method of useful components comprises the following steps: mixing 60-99 weight% of bisphenol A tar and 1-40 weight% of phenol tar; heat-decomposing the tar mixture; and collecting effective components from thermal pyrolysate. The thermal decomposition temperature is 250-285 deg. Celsius. The stay time of the tar mixture is 10 minutes to 2 hours. The sodium sulfate contained in the phenol tar works as a catalyst.

Description

Method for recovering useful ingredient from bisphenol A tar}

The present invention relates to a method for recovering useful components through co-cracking of bisphenol A tar and phenol tar.

Bisphenol A is prepared by condensing acetone with excess phenol in the presence of an acidic catalyst or cation exchange resin. The crude product is an unwanted product other than bisphenol A, ie p, o'- and o, o'-2,2-hydroxyphenylpropane, p-isopropenylphenol, and poly- by secondary condensation and cyclization reactions. Contains aromatic byproducts. During the separation of the final product by rectification, further by-products are produced because more condensation and cyclization reactions occur in the high temperature region of the rectification column. The total amount of tar produced in this way can reach 10% or more of the commercial product.

Although the average content of valuable products, such as phenols and bisphenols in tar, is 20 to 60%, known processing methods for recovering these valuable products are technical difficulties and require substantial investment.

Tar by-products are present at the bottom of the final rectification column in conventional bisphenol A plants and are usually combusted or processed by known methods.

There is a method of making a low boiling product comprising initial samples (phenol and acetone) that can be recycled to the bisphenol A synthesis process by catalytic cracking and catalytic hydrogen cracking in the presence of hydrogen. However, the use of complex catalysts, hydrogen and elevated pressures increase and complicate process costs. There is a series of catalysts known to perform tar cracking under relatively mild conditions.

For example, according to French Patent No. 2364195 (1978), pyrolysis of bisphenol tar can be carried out at 150 to 250 ° C. in the presence of sodium hypophosphite, and US Pat. No. 4277628 (1981) in the presence of aluminum isopropylate. It is disclosed that tar cracking can be performed to obtain phenol in good yield. A.C. CCCP 829610 (1981) describes the use of an alkali catalyst for the decomposition of bisphenol tar under reduced pressure. US patent 3466337 discloses a tar cracking method for adding sodium salts of organic acids and minerals. All of these methods have the disadvantage that the yield is low and the solid production rate is high so that solids can precipitate in the apparatus and contaminate the catalyst. The recycle stream of secondary distillate containing traces of catalyst may degrade the activity of the bisphenol A synthesis catalyst and result in further byproduct formation.

Another attempt to solve this problem is to eliminate the possibility of the catalyst mixture passing through the bisphenol A synthesis zone, isomerizing the tar component to the desired product. According to US Pat. No. 4,414,961 (1980) and 4192954 (1980), distillation of bisphenol A remaining at the bottom after distillation with equal mass ratios of pure phenol and the mixture in an amount of about 4% by weight of anhydrous HBr or HCl gas It can be stirred at the average temperature in the presence. The process using HCl is carried out at a predetermined pressure. In some cases, a three-component mixture consisting of tar, phenol and by-products of the tar recovery process after distillation is used. Further treatments include halogen hydride removal and product crystallization. This method provides bisphenol A in high yield, but involves a number of steps and requires special corrosion resistance devices.

In this regard, the most practical and inexpensive processing methods include thermal decomposition of tar, followed by separation or crystallization of the light components produced during decomposition, or the like.

The phenol tar by-products produced when preparing phenol and acetone from cumene processes can be thermally cracked by methods known per se. This process is carried out at a temperature of 350 to 500 ° C. The thermal cracking product is separated by distillation (US Pat. No. 3391198 (1968)).

According to A.C.CCCP No. 12258,601 (1986), phenol tar is diluted prior to decomposition with a high molecular weight aromatic compound such as Baltic shale oil (grade kerosene-70) with a ratio of tar to shale oil of 1.3: 2.5. Processing conditions are made into the pressure of 3-7 MP, the temperature of 400-430 degreeC, and the reaction time of 5-20 minutes. The liquid product obtained is separated by distillation. This process is carried out under relatively stringent conditions and low yields of phenol (4-5%) and cumene (10-15%) are obtained. This processing method also requires the addition of shale oil.

There is also a method of adding bisphenol A to high boiling bisphenol A tar in a batch or continuous pyrolysis process under atmospheric pressure at 300 to 380 ° C. and continuously removing the formed product (ZN Verhovkaya-Diphenolpropane, Moscow: Chemie, 1971, c. 182). After cracking, the final tar residue in the initial tar amount of about 30% is incinerated. The distilled fraction contains a mixture of 40% phenol, 15% alkylphenol, and phenols boiling at temperatures above 270 ° C. This method has the disadvantage that the production rate of phenol obtained from the bisphenol-A tar components is low and substantially the bisphenol-A contained in the initial mixture is completely lost. Another problem is that the viscosity of the bottom liquid is so high that it is very difficult to take it out and transport it to the incinerator.

U.S. Pat.No. 5,425,251 discloses mixing bisphenol-A tar produced when condensing phenol and acetone to produce bisphenol-A with phenol tar produced when making phenol from cumene, and these tars at about 290 ° C. A process for recovering phenol, alpha-methylstyrene and cumene from a mixture of bisphenol-A tar and phenol tar is disclosed, comprising thermal decomposition at a temperature in the range of from about 360 ° C., although preferred embodiments of this patent According to the present invention, the amount of bisphenol A tar is smaller than that of phenol tar, the cracking temperature is high, the residence time is considerably long (20 hours), and in addition to phenol, alpha-methylstyrene (AMS) and cumene, isopropenyl phenol (IPP) Do not recover.

U.S. Pat.

As mentioned above, there are a number of methods for recovering by-products from BPA and phenol tar, but more advantageous methods have not yet been developed.

It is therefore an object of the present invention to provide a more advantageous method of recovering useful components from phenolic tars including bisphenol A.

Another object of the present invention is to provide a method for recovering isopropenyl phenol (IPP) as an active ingredient in phenol tars containing bisphenol A.

The present invention comprises the steps of mixing 60 to 99% by weight of bisphenol A tar and 1 to 40% by weight of phenol tar; Thermally decomposing the tar mixture; And it provides a method for recovering the useful component in the phenolic tar comprising the step of recovering the useful component from the thermal decomposition product.

In order to increase the recovery of useful components in the method of the present invention, it is possible to mix 80 to 95% by weight of bisphenol A tar and 5 to 20% by weight of phenol tar.

In the process of the present invention, the pyrolysis temperature may be 250 to 285 ° C., and the residence time of the tar mixture may be 10 minutes to 2 hours.

In the process of the present invention, sodium sulfate contained in phenol tar acts as a catalyst, and thus cracking can be carried out without the use of additional catalyst.

According to the method of the present invention, useful components including phenol, p, p-bisphenol A, cumene, alpha-methylstyrene (AMS) and isopropenyl phenol (IPP) can be recovered.

The present invention can provide a more advantageous method for recovering the useful components in phenol tars including bisphenol A, in particular can provide a method for recovering isopropenyl phenol (IPP) as an active ingredient.

Hereinafter, the present invention will be described in detail.

Recovery method of useful components in phenol tar according to the present invention comprises the steps of mixing bisphenol A tar; Thermally decomposing the tar mixture; And recovering the useful component from the thermal decomposition product.

First, bisphenol A tar and phenol tar are mixed.

The mixing ratio of bisphenol A tar and phenol tar is 60 to 99% by weight of bisphenol A tar and 1 to 40% by weight of phenol tar, preferably 80 to 95% by weight of bisphenol A tar and 5% of phenol tar in order to increase the recovery of useful ingredients. To 20% by weight.

Since the object of the present invention is to recover the active ingredient from bisphenol A tar, it is preferable to use more bisphenol A tar than phenol tar, and in particular to use an excess of bisphenol A tar, in which phenol tar serves to provide a catalyst. Do it. Since it is not the object of the present invention to recover the active ingredient from phenol tar, it is preferable to add as little as possible as long as the phenol tar serves as a catalyst.

The tar mixture is then thermally decomposed.

Any thermal cracking reactor can be used, but it is most suitable to use a distillation column type thermal cracker. A distillation columnar reactor provides an optimum and convenient separation of the overhead product stream from the bottom waste stream.

In addition, CSTR (Continuous Stirred Tank Reactor) type devices are commonly used. In addition, any equipment can be used as long as it is equipped with agitation, temperature control, supply and discharge of raw materials, and condensation and recovery of steam.

The feed stream enters the middle of the column. The distilled fraction exiting the top of the column is divided into two parts, one of which is recycled to the recovery process of valuable products and the other is provided for reflux at the top of the column.

A preferred apparatus for carrying out the pyrolysis is a column reactor with a reboiler port, but the lightweight product of the pyrolysis can be recovered above the feed stream inlet of the mixed tar and the heavy product can be removed and disposed below the feed point. Any suitable reactor can be used.

The pyrolysis temperature is preferably 250 to 285 ° C. If the pyrolysis temperature is too low, the recovery rate is lowered. As the pyrolysis temperature is increased, the recovery rate is increased, but the energy cost is increased accordingly, and it is difficult to increase the temperature above 285 ° C. under the facility conditions of the field, so the above range is appropriate.

The residence time of the tar mixture is preferably 10 minutes to 2 hours. If the residence time is too short, the recovery rate of the active ingredient is low, and there is no economical. If the retention time is too long, the recovery rate is high, but the size of the device is large and the energy cost is high.

In a conventional method, a strong base or a strong acid is used as a catalyst, but in the method of the present invention, sodium sulfate contained in phenol tar serves as a catalyst, and thus cracking can be performed without using an additional catalyst.

Next, the useful component is recovered from the thermal decomposition product.

Preferably, the useful component is recovered from the distilled fraction, ie, the lightweight product of pyrolysis that is discharged above the feed stream inlet.

The recovery method is not particularly limited and may be recovered by conventional separation methods such as distillation, crystallization and chromatography according to the characteristics of the individual components.

According to the present invention, useful components such as phenol, p, p-bisphenol A, cumene, AMS can be recovered from bisphenol A tar and phenol tar, and particularly, IPP can be recovered.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only for illustrating the present invention, and the scope of the present invention is not limited by the following Examples.

Example 1

After supplying 95% by weight of bisphenol A tar and 5% by weight of phenol tar to the distillation column type thermal cracking device, pyrolysis was performed at 280 ° C, and the residence time was set to 1 hour. The useful components of the content shown in Table 1 were separated and recovered from the distillation fraction.

[Example 2]

As in Example 1, 90 wt% of bisphenol A tar and 10 wt% of phenol tar were supplied.

[Example 3]

As in Example 1, 80 wt% bisphenol A tar and 20 wt% phenol tar were supplied.

Example 4

In the same manner as in Example 1, 70 wt% bisphenol A tar and 30 wt% phenol tar were supplied.

[Example 5]

As in Example 1, 60 wt% bisphenol A tar and 40 wt% phenol tar were supplied.

Comparative Example 1

After supplying 0% by weight of bisphenol A tar and 100% by weight of phenol tar to the distillation column type thermal cracking device, pyrolysis was performed at 315 ° C, and the residence time was set to 20 hours.

Comparative Example 2

Same as Comparative Example 1, except that 9.1 wt% bisphenol A tar and 90.9 wt% phenol tar were supplied.

[Comparative Example 3]

As in Comparative Example 1, 25 wt% of bisphenol A tar and 75 wt% of phenol tar were supplied.

[Comparative Example 4]

As in Comparative Example 1, 50 wt% of bisphenol A tar and 50 wt% of phenol tar were supplied.

[Test Example]

Table 1 shows the contents of the useful components recovered in Examples 1 to 5, was quantitatively analyzed by Gas Chromatography (GC).

In Table 1, phenol to AMS value means weight% in the distillate, distillate means weight% generated relative to the raw material supplied, and active material also means weight% of the active substances generated in the supplied raw material. do. For example, in the case of Example 1, if 1 kg of tar per hour was added to the cracker, 462 g of distillate was generated per hour, of which the concentration of phenol to AMS was 63.3 wt% to 0.46 wt%, the amount of these active ingredients. Calculate and add up to 378 g.

phenol p, p-BPA p-IPP Cumen AMS Distillate Effective substance Example 1 63.3 0.45 17.4 0.13 0.46 46.2 37.8 Example 2 51.8 0.32 21.4 0.20 0.68 67.7 50.4 Example 3 51.4 0.22 18.7 0.46 1.5 66.8 48.3 Example 4 47.3 0.17 15.4 0.74 2.5 65.0 43.0 Example 5 44.7 0.13 13.5 1.0 3.2 59.2 37.0 Comparative Example 1 49.0 23.2 27.8 43.9 Comparative Example 2 52.3 21.1 26.6 43.1 Comparative Example 3 58.7 18.8 22.5 40.7 Comparative Example 4 69.6 14.9 15.5 37.4

As can be seen in Table 1, according to the embodiment of the present invention, the active ingredient was recovered up to about 50%, in particular, a large amount of IPP could be obtained.

On the other hand, in the case of using an excess of phenol tar, high pyrolysis temperature, and long residence time, cumene and AMS recovery was large, but IPP could not be obtained.

Claims (6)

Mixing 60 to 99% by weight bisphenol A tar and 1 to 40% by weight phenol tar;
Thermally decomposing the tar mixture; And
Recovering the useful component from the thermal decomposition product,
Method for recovering useful components from phenolic tar.
The method of claim 1,
Mixing 80 to 95% by weight of bisphenol A tar and 5 to 20% by weight of phenol tar,
Method for recovering useful components from phenolic tar.
The method of claim 1,
Pyrolysis temperature is 250 to 285 ° C,
Method for recovering useful components from phenolic tar.
The method of claim 1,
The residence time of the tar mixture is 10 minutes to 2 hours,
Method for recovering useful components from phenolic tar.
The method of claim 1,
Sodium sulfate in phenol tar acts as a catalyst,
Method for recovering useful components from phenolic tar.
The method of claim 1,
Useful ingredients include phenol, p, p-bisphenol A, cumene, alpha-methylstyrene (AMS) and isopropenyl phenol (IPP),
Method for recovering useful components from phenolic tar.