JP6206284B2 - Method for producing high purity phenol, α-methylstyrene and cumene - Google Patents

Description

  The present invention relates to a method for efficiently obtaining high-purity phenol, α-methylstyrene and cumene in a cumene process phenol production process.

  Phenol is industrially generally produced by the cumene method. In the production of phenol by the cumene method, phenol and acetone are obtained by acid-decomposing and then distilling cumene hydroperoxide produced by the oxidation of cumene. Here, the distillation residue after obtaining phenol and acetone contains active ingredients such as cumylphenol and undistilled phenol by-produced in the acid decomposition reaction. Therefore, cumylphenol is recovered after being thermally decomposed into phenol and α-methylstyrene and distilled together with a solution obtained by acid-decomposing the cumene hydroperoxide.

  However, when the pyrolysis product is distilled as it is to recover phenol and α-methylstyrene and distilled together with the acid-decomposed liquid, low boiling point impurity components are likely to be mixed into the phenol and acetone. Therefore, the pyrolysis product is distilled in the first distillation column to distill phenol and α-methylstyrene from the top of the column, and cooled so that components having a boiling point lower than α-methylstyrene are not substantially condensed. , Phenol and α-methylstyrene are recovered as condensate. Then, the non-condensed components are supplied to the second distillation column, and the remaining phenol and α-methylstyrene are recovered as a column bottom liquid, and components having a lower boiling point than α-methylstyrene are distilled off from the column top. A method has been proposed (see Patent Document 1). However, since this method requires two or more distillations and cooling, in the cumene process phenol production process, efficient and high-purity phenol and acetone can be easily obtained using the active ingredients present in the production process. There was a need to develop a method to obtain.

Japanese Patent Laid-Open No. 2003-81897

  The present invention has been made in order to solve the above-described problems. In the production process of cumene method phenol, an effective component such as high-purity phenol and α-methylstyrene can be easily and efficiently obtained. It is an object to provide a method.

  As a result of intensive studies by the present inventors to solve the above-mentioned problems, in the production process of cumene method phenol, pyrolysis of heavy components from which phenol and acetone produced by acid decomposition of cumene hydroperoxide are removed is thermally decomposed. When a fraction containing active ingredients such as phenol and α-methylstyrene is obtained by distilling the pyrolysis product obtained in this way, light boiling components are removed from the top of the column and heavy components are removed from the bottom of the column. At the same time, it was found that only the active ingredients existing in the production process can be efficiently obtained from the middle part of the tower. The present invention has been completed based on these findings.

That is, the first gist of the present invention is that, in the production process of cumene method phenol, after acid and decomposing cumene hydroperoxide to produce phenol and acetone, the phenol and acetone are obtained. A pyrolysis product is obtained by pyrolyzing the heavy component, and phenol, α-methylstyrene and cumene in the pyrolysis product are obtained by distilling the pyrolysis product. In the distillation, the light boiling component is removed from the top of the column, the heavy component is removed from the bottom of the column, and phenol, α-methylstyrene and cumene are contained from the middle of the column. The present invention resides in a method for obtaining phenol, α-methylstyrene and cumene, characterized by obtaining a fraction. The second aspect of the present invention is a method for obtaining phenol, α-methylstyrene and cumene described in the first aspect, wherein the phenol, α-methylstyrene and cumene from the middle part of the column are obtained. The present invention resides in a method for obtaining phenol, α-methylstyrene, and cumene, wherein the amount of the fraction to be contained is adjusted so that the temperature at the bottom of the column is constant.

  ADVANTAGE OF THE INVENTION According to this invention, in the manufacturing process of cumene method phenol, it becomes possible to acquire efficiently an effective component phenol, (alpha) -methylstyrene, and cumene by a simple method. Moreover, by returning these active ingredients to the cumene process phenol production process, it becomes possible to produce highly pure phenol and acetone more efficiently.

It is a figure which shows the preferable specific example of the method of acquiring the phenol of this invention, (alpha) -methylstyrene, and cumene.

  The method for obtaining phenol, α-methylstyrene and cumene according to the present invention comprises producing cumene hydroperoxide by acid decomposition in the cumene process phenol production process, and then producing the phenol and acetone. To obtain a pyrolysis product by pyrolyzing the heavy component, and distilling the pyrolysis product to obtain phenol in the pyrolysis product, A fraction containing α-methylstyrene and cumene is obtained.

Here, cumene hydroperoxide can be obtained by oxidizing cumene. The raw material cumene is usually obtained by reacting benzene and propylene. In the cumene oxidation reaction, acetophenone is by-produced.
The acid decomposition of cumene hydroperoxide is preferably performed using sulfuric acid. Moreover, it is preferable to wash with water after neutralizing using an aqueous alkali solution such as sodium hydroxide after acid decomposition. In the acid decomposition reaction of cumene hydroperoxide, α-methylstyrene, cumylphenol and α-methylstyrene dimer are by-produced.

  Phenol and acetone produced by acid decomposition are usually sequentially removed in the order of acetone and phenol by distillation. The heavy component obtained by removing phenol and acetone contains an active component such as cumylphenol. Therefore, the effective component contained in the heavy component is recovered by distilling the heavy component after pyrolysis. The thermal decomposition is performed at a temperature at which cumylphenol or the like is decomposed, and specifically, it is normally performed at 250 to 350 ° C. In pyrolysis, cumene, benzene and ethylbenzene are also by-produced.

The cumene process for phenol production such as cumene oxidation, acid decomposition of cumene hydroperoxide, removal of phenol and acetone and thermal decomposition of heavy components according to the present invention may be carried out by any known method. . Moreover, it is preferable to remove the light boiling component contained in the heavy component by distillation before thermal decomposition.
In the composition (pyrolysis product) obtained by pyrolyzing heavy components, benzene, ethylbenzene, cumene produced by pyrolysis, α-methylstyrene, phenol, acetophenone, cumylphenol and α-methylstyrene dimer and the like are included.

  In the method for obtaining phenol, α-methylstyrene and cumene of the present invention, when the above pyrolysis product is distilled, light boiling components are removed from the top of the column, heavy components are removed from the bottom of the column, and the middle of the column is removed. A fraction containing phenol, α-methylstyrene and cumene is obtained from the portion (this distillation may hereinafter be referred to as “distillation according to the present invention”). That is, the distillation according to the present invention can be divided into three or more fractions by one distillation column.

  On the other hand, in the conventionally known pyrolysis product distillation, phenol and α-methylstyrene are distilled from the top of the column by distillation in the first distillation column, and the top distillate is phenol and α-methylstyrene. Condenses. At that time, the components having a lower boiling point than α-methylstyrene are cooled so as not to condense, and phenol and α-methylstyrene in the overhead distillate are recovered as a condensate. The uncondensed components are supplied to the second distillation column and the remaining phenol and α-methylstyrene are recovered as the bottom liquid, and components having a boiling point lower than α-methylstyrene are distilled off from the top of the column. . As described above, the distillation according to the present invention can recover a fraction containing phenol and α-methylstyrene while being a very simple method as compared with known distillation. Here, the cumene contained in the fraction obtained from the middle part of the column by distillation according to the present invention can be reused as raw material cumene by distillation.

  The distillation according to the present invention is preferably performed by adjusting the amount of the fraction containing phenol, α-methylstyrene and cumene from the middle of the column so that the temperature at the bottom of the column is constant. “Temperature constant” means that the upper and lower limits are within 20 ° C. The temperature at the bottom of the column is specifically preferably 180 ° C or higher, more preferably 210 ° C or higher, and preferably 260 ° C or lower, and 230 ° C or lower. It is preferable.

A particularly preferred embodiment of the distillation according to the present invention will be described with reference to FIG.
In FIG. 1, a composition 1 obtained by thermally decomposing heavy components is distilled using a distillation column 10 to remove light boiling components 2 from the top of the column and heavy components 4 from the bottom of the column. Fraction 3 containing phenol, α-methylstyrene and cumene is obtained from the middle part. Here, light boiling fraction 2 contains benzene, ethylbenzene, cumene, etc., fraction 3 contains phenol, α-methylstyrene and cumene, and heavy fraction 4 contains acetophenone, cumylphenol, and α-methylstyrene dimer. It is preferable to adjust the distillation conditions so that. This is because the fraction 3 can be reused by distillation together with a solution obtained by acid-decomposing cumene hydroperoxide. Moreover, the cumene contained in the fraction 3 can also be used as a raw material cumene. That is, since the distillation according to the present invention can separate three or more fractions using a single distillation column, only effective components can be efficiently extracted with high purity. Therefore, in the distillation according to the present invention, the fraction 3 contains a large amount of effective components such as phenol, α-methylstyrene and cumene, and the components having a lower boiling point than cumene and the components having a higher boiling point than phenol are reduced. It is preferable to adjust to. In particular, since benzene is a carcinogenic substance, it is preferable that acetone obtained by the cumene phenol production process is not mixed when used as a cleaning agent in the medical field or food field. Therefore, when the phenol, α-methylstyrene and cumene contained in the fraction 3 are reused by distillation together with a solution obtained by acid decomposition of cumene hydroperoxide, the fraction 3 is distilled so as not to be contained in the fraction 3. It is preferable to do.

  In FIG. 1, the amount of fraction 3 obtained from the middle of the column is adjusted by a metering valve (not shown) so that the temperature in the thermometer 300 at the bottom of the column is constant. Here, the temperature in the thermometer 300 at the bottom of the tower may be adjusted by the flow rate of the heat medium flowing through the heat exchanger 40 at the bottom of the tower. In terms of easy follow-up, adjustment by the metering valve 301 is preferable.

  In the distillation according to the present invention, the light boiling point 2 from the top of the column is cooled by the heat exchanger 20 and then put into the reflux vessel 30, a part of which is refluxed from the reflux line 2b to the distillation column 10, and the remainder is discarded. It is preferable to discard from 2a. The amount of reflux from the reflux line 2b is preferably such that the liquid level of the reflux vessel 30 is kept constant in the level controller 100, and the amount of waste from the waste line 2a is the amount of benzene contained in the fraction 3. It is preferable to adjust using a metering valve 200 so that is less than a desired amount.

  Hereinafter, the contents of the present invention will be described with reference to examples. However, the present invention is not limited to the following examples. In the following examples, the composition of each fraction was calculated from the material balance in the distillation purification system after acid decomposition of cumene hydroperoxide.

[Example 1]
Phenol and acetone were produced by acid decomposition of cumene hydroperoxide obtained by oxidizing cumene, and then removed by distillation of phenol and acetone. The composition obtained by pyrolyzing the remaining heavy components was distilled. In the distillation, light boiling components were removed from the top of the column, heavy components were removed from the bottom of the column, and a fraction containing phenol, α-methylstyrene and cumene was obtained from the middle of the column. The liquid level of the reflux vessel at the top of the column was kept constant by the amount of reflux to the distillation column. Here, the amount of the fraction containing phenol, α-methylstyrene and cumene from the middle of the column was adjusted so that the temperature at the bottom of the column would be 222 to 223 ° C. As a result, compositions having the following compositions were obtained as a fraction from the middle of the column and a heavy fraction from the bottom of the column.

(Distillation from the middle of the tower)
Benzene; 39 ppm by weight
Cumene; 31.69% by weight
α-methylstyrene; 7.74% by weight
Phenol; 42.46% by weight
Acetophenone; 0.011% by weight
Other; 18.10% by weight
(Heavy from the bottom of the tower)
Phenol; 8.33 wt%
Acetophenone; 75.55% by weight
Cumenephenol; 1.57% by weight
α-methylstyrene dimer; 3.30% by weight
Other heavy components: 11.25% by weight

[Example 2]
In Example 1, except that the distillation method of the composition obtained by pyrolysis was changed as follows, the light boiling component was removed from the top of the column and the heavy component was removed from the bottom of the column. A fraction containing phenol, α-methylstyrene and cumene was obtained from the middle part of the column. The temperature at the bottom of the tower was adjusted to 220 to 224 ° C. by the flow rate of the heat medium flowing through the heat exchanger 40 at the bottom of the tower. The liquid level of the reflux vessel at the top of the column was kept constant by the amount of the fraction containing phenol, α-methylstyrene and cumene from the middle of the column. As a result, a composition having the following composition was obtained as a heavy component from the bottom of the tower.

(Heavy from the bottom of the tower)
Phenol; 20.04% by weight
Acetophenone; 60.62% by weight
Cumenephenol; 1.82% by weight
α-methylstyrene dimer; 3.43% by weight
Other heavy components: 14.09% by weight

  From Examples 1 and 2, it was confirmed that a fraction containing phenol, α-methylstyrene and cumene can be obtained easily and efficiently by the method of the present invention. In particular, in Example 1, compared with Example 2, since the amount of phenol contained in the heavy portion at the bottom of the column is small, acquisition of a fraction containing phenol, α-methylstyrene and cumene from the middle of the column. It was also found that the amount of phenol contained in the heavy component at the bottom of the column can be reduced by adjusting the amount so that the temperature at the bottom of the column is constant. Moreover, it seems that it becomes possible to manufacture highly pure phenol more efficiently by returning the active ingredient obtained here to the manufacturing process of cumene method phenol.

1: pyrolyzed composition 2: light boiling point 2a: waste line 2b: reflux line 3: fraction 3 from the middle of the column
4: Heavy fraction 10: Distillation tower 20, 40: Heat exchanger 30: Reflux vessel 100: Level controller 200: Metering valve 300: Thermometer

Claims (1)

In the production process of cumene method phenol, phenol and acetone are produced by acid decomposition of cumene hydroperoxide, and then the heavy component is separated by obtaining the phenol and the acetone, and the heavy component is A method for obtaining a pyrolysis product by pyrolysis, and obtaining a fraction containing phenol, α-methylstyrene and cumene in the pyrolysis product by distilling the pyrolysis product, In the distillation, light-boiling components are removed from the top of the column, heavy components are removed from the bottom of the column, a fraction containing phenol, α-methylstyrene and cumene is obtained from the middle of the column, and the middle of the column is obtained. phenol from part, to adjust the acquisition of fraction comprising α- methyl styrene and cumene as the temperature of the tower bottom becomes constant The symptom, phenol, how to get the α- methylstyrene and cumene.

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