JP2005002004A - Method for producing phenol compound and acetone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a phenol compound and acetone by which cumene hydroperoxides are rapidly and uniformly mixed with sulfuric acid and the resultant mixture is subjected to acidolysis under controlled temperature conditions. <P>SOLUTION: The method for producing the phenol compound and the acetone is characterized as follows. A flow-through type reactor having a microtubular reaction channel is used as a reactor and the sulfuric acid dissolved in a solubilizing agent is fed to the reactor. The cumene hydroperoxides are decomposed with the sulfuric acid in the microtubular reaction channel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for efficiently producing high-quality phenol and acetone.
[0002]
[Prior art]
A process for producing phenol and acetone by oxidizing cumene to cumene hydroperoxide (hereinafter referred to as “CHP”) and acid-decomposing it with an acid catalyst such as sulfuric acid to form phenol and acetone is widely performed industrially. Is the way.
This acid decomposition reaction is accompanied by a large exotherm, and the reaction rate is very fast, so it is difficult to control the reaction temperature and suppress side reactions. As one of the solutions, it has been proposed that a part of the produced acetone is refluxed and evaporated to the reaction system, the reaction temperature is controlled by the latent heat of evaporation, and side reactions are suppressed. However, this method is not an efficient method because the acid decomposition reactor becomes large. As a method for improving the efficiency of the acid decomposition reaction, CHP acid decomposition is carried out in a tubular reactor, and a part of the decomposition product is returned to the reactor (see Patent Document 1). There have been proposed a method of performing in a mixed reactor (see Patent Document 2), a method of performing acid decomposition of CHP in a tubular reactor in which phenol: acetone: cumene is kept at a specific molar ratio (see Patent Document 3) Yes.
[0003]
However, these methods are insufficient in controlling the reaction temperature, and the product cannot be sufficiently prevented from being colored.
When decomposing CHP with sulfuric acid, it is important to rapidly and uniformly mix CHP and sulfuric acid together with controlling the heat of reaction. However, while CHP is hydrophobic, sulfuric acid is water-soluble and the amount thereof is significantly smaller than that of CHP, so it is difficult to mix them both quickly and uniformly.
[0004]
[Patent Document 1]
JP 2000-178214 A [Patent Document 2]
JP-A-9-20699 [Patent Document 3]
JP-T-2001-506251 gazette
[Problems to be solved by the invention]
Accordingly, the present invention provides a method for producing a phenol compound and acetone by rapidly and uniformly mixing cumene hydroperoxides and sulfuric acid and acid-decomposing the mixture under controlled temperature conditions. Let it be an issue.
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the inventors of the present invention quickly dissolved cumene hydroperoxides and sulfuric acid by dissolving sulfuric acid in a compatibilizing agent that is an organic solvent compatible with the sulfuric acid and mixing it with cumene hydroperoxides. It was found that they can be mixed uniformly. Then, the present inventors have found that the reaction can be carried out under controlled temperature conditions by supplying this mixture to a flow reactor having a microtubular reaction channel and causing acid decomposition, and the present invention has been achieved.
[0007]
That is, the present invention uses a flow reactor having a microtubular reaction channel as a reactor, supplies sulfuric acid dissolved in a compatibilizer to the reactor, and cumene hydroperoxides in the microtubular reaction channel. The present invention resides in a method for producing a phenol compound and acetone, which is decomposed by sulfuric acid.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
Cumene hydroperoxides that provide phenolic compounds and acetone include alkyl group-substituted cumene hydroperoxides such as CHP and methyl cumene hydroperoxide. Phenol from CHP and the corresponding alkyl-substituted phenol from alkyl group-substituted cumene hydroperoxide together with acetone. Hereinafter, a case where phenol and acetone are produced by decomposing CHP with sulfuric acid will be described.
As CHP supplied to the reactor in the present invention, an oxidation reaction product of cumene containing CHP usually produced by cumene oxidation is used. This oxidation reaction product usually contains unreacted cumene, CHP and other products, but this mixture may be used as it is, or it may be used after removing cumene and the like by distillation or the like. Good. Preferably, CHP is mixed with a compatibilizing agent used for compatibilization of sulfuric acid described later and supplied to the reactor. This operation facilitates quick and uniform mixing with sulfuric acid dissolved in the compatibilizing agent. CHP is fed to the reactor so that its concentration in the total feed fed to the reactor is usually 1% by weight or more, preferably 5% by weight or more. If the CHP concentration in the total feed is too low, the acid decomposition reaction will not proceed sufficiently. Conversely, if the CHP concentration is too high, a rapid exothermic reaction occurs, and the product may be colored by by-products. The CHP concentration in the total feed is usually 50% by weight or less, preferably 30% by weight or less.
[0009]
Sulfuric acid is dissolved in a compatibilizing agent, that is, an organic solvent compatible therewith, and supplied to the reactor. Usually, concentrated sulfuric acid is dissolved in the compatibilizing agent so as to be 100 to 10,000 ppm. Sulfuric acid is fed to the reactor so that the concentration in the total feed fed to the reactor is usually 20 to 2000 ppm by weight, preferably 50 to 500 ppm by weight. If the concentration is too low, the reaction does not proceed sufficiently, while if it is too high, a sudden exothermic reaction may occur.
[0010]
Any compatibilizer can be used as long as it is compatible with sulfuric acid and is a non-reactive solvent. Specific examples include water-soluble ketones such as acetone; and proton solvents such as phenol and water-soluble alcohols. Of these, the reaction product phenol is preferable because a part of the phenol produced in the industrial process can be recovered and recycled.
[0011]
When phenol is used as a compatibilizing agent, the ratio of phenol to CHP fed to the reactor is usually greater than 1. Preferably it is 1.5 to 3 times by weight. If the amount of phenol in the reactor feed is larger than that of CHP, mixing of CHP and sulfuric acid becomes easier, so that the reaction rate is improved, no rapid exothermic reaction occurs, and coloring by by-products can be prevented. it can.
[0012]
As the reactor, a flow reactor having a microtubular reaction channel is used. The cross-sectional shape of the microtubular reaction channel may be any of a circle, an ellipse, a square or a rectangle. The equivalent diameter of the flow path is usually 10 to 30000 μm, preferably 50 to 2000 μm, particularly preferably 100 to 500 μm. The equivalent diameter is a value defined by 4 * S (cross-sectional area) / l (circumference length) when the reaction tube is cut along a cross section perpendicular to the direction of travel of the reaction solution. In the case of a perfect circle, the diameter corresponds to the equivalent diameter. Therefore, since the production capacity of one microtubular reaction channel is small, a reactor having a large number of microtubular reaction channels is used so as to obtain a desired production capacity. A typical example of such a reactor is a shell-and-tube type multi-tubular reactor, and the reaction temperature can be easily controlled by circulating a refrigerant on the shell side.
[0013]
The length of the reaction tube is usually 10 cm to 10 m, preferably 20 cm to 8 m, particularly preferably 30 cm to 5 m.
The material of the reaction tube is arbitrary as long as it is not corroded by the reaction solution to be circulated. In order to efficiently remove reaction heat from the wall surface of the reaction tube, those having high thermal conductivity are preferable, and in order to ensure strength against the pressure in the reaction tube, those having excellent mechanical strength are preferable. Specifically, a metal, glass, resin, ceramic, etc. are mentioned, and metals, such as a stainless steel pipe, are preferred among these. In addition, in order to improve the corrosion resistance with respect to the reaction solution, the inner wall of the reaction tube may be coated.
[0014]
CHP and sulfuric acid may be directly supplied to the microtubular reaction channel, or may be mixed in advance to form a uniform mixture and then supplied to the microtubular reaction channel. In the former case, the merging portion that joins CHP and sulfuric acid has a constricted portion that is formed in the confluent portion and has a cross-sectional area smaller than the sum of the cross-sectional areas of the introduction flow channels, and a downstream portion of the constricted portion. It is preferable to have a configuration (see Japanese Patent Application Laid-Open No. 2002-292271) including an enlarged portion provided on the side and having a cross-sectional area larger than the cross-sectional area of the throttle portion. In the latter case, it is preferable that the mixing is performed quickly and the mixture is immediately allowed to flow into the microtubular reaction channel.
[0015]
The CHP and sulfuric acid supplied to the reactor are preferably subjected to degassing treatment in advance to prevent the generation of bubbles in the minute reaction channel. Examples of the degassing treatment method include ultrasonic treatment and decompression treatment (see JP 2002-273206 A).
Moreover, in order to efficiently obtain a large amount of product, it is preferable to carry out the reaction by arranging a plurality of, for example, about 100 to 10,000 flow-type microtubular reaction paths in parallel.
[0016]
The reaction temperature is arbitrary, but if the temperature is too low, the reaction does not proceed easily. Conversely, if the temperature is too high, the product may be colored. The reaction pressure is usually normal pressure to 50 atm, preferably normal pressure to 10 atm. Moreover, reaction residence time is 0.01 to 10 minutes normally, Preferably it is 0.5 to 5 minutes.
The reaction mixture after acid decomposition is usually obtained by neutralizing sulfuric acid used as a catalyst, and then separating and obtaining the target phenol and acetone by a known method such as distillation. Part of the phenol obtained here can be used as a compatibilizing agent. In the case where a plurality of flow-type microtubular reaction paths are arranged in parallel, the target product may be separated after combining the reaction product liquid obtained from the plurality of reaction tubes, or the reaction product liquid for each reaction tube These may be combined after the desired product has been separated from the product.
[0017]
【Example】
The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
[Example]
A mixed solution consisting of 80 parts by weight of a CHP-containing mixture (CHP 35% by weight, cumene 60% by weight, dimethyl carbinol 5% by weight) obtained by the oxidation reaction of cumene and 10 parts by weight of phenol was placed in a 10 mL microsyringe, and a supply tube ( 1A) was supplied into the syringe pump (2A). Separately, a sulfuric acid / phenol solution (1.0% by weight sulfuric acid) was placed in a 1 mL microsyringe and supplied into the syringe pump (2B) from the supply tube (1B). The CHP / phenol solution is continuously fed at a flow rate of 0.5 mL / h, and the sulfuric acid / phenol solution is continuously fed at a flow rate of 0.0089 mL / h from the introduction pipe (3A) and the introduction pipe (3B). After merging, it was supplied to a flow-through microtubular reaction channel (5) installed in a thermostat at 0 ° C. or lower. The acid decomposition reaction was stopped by adding 2 wt% ammonia water supplied through the supply pipe (1C), the syringe pump (2C) and the introduction pipe (3C) to the reaction product. The portion after the merging portion of the CHP / phenol solution and sulfuric acid / phenol solution was used as a reaction tube, and the length was 20 cm. A Teflon (R) tube having an inner diameter of 0.5 mm and an outer diameter of 1.5 mm was used from the microsyringe to the reaction tube, and a stainless steel tube having an inner diameter of 0.25 mm and an outer diameter of 1.5 mm was used as the reaction tube. The sulfuric acid concentration at the junction of the CHP / phenol solution and sulfuric acid / phenol solution was 100 ppm, and the residence time of the reaction tube was 69 seconds.
[0018]
When the reaction product solution was analyzed by GC, the conversion rate of CHP was 100%, and the target phenol was obtained in a yield of 92.6%. Further, acetophenone as a by-product was obtained in a yield of 1.2% and 4-cumylphenol was obtained in a yield of 6.2%, and dicumyl peroxide was not detected. The reaction product solution had an absorbance of about 0.1 at 400 nm and was hardly colored. The conversion rate and yield were determined by the following formula.
[0019]
Conversion = number of moles of reacted CHP / number of moles of fed CHP = number of moles of product / number of moles of CHP fed [Comparative Example]
A CHP / phenol solution and a sulfuric acid / phenol solution having the same composition as in the examples were reacted in a batch-type stirred reactor. The yield of phenol was less than 90%, and the absorbance at 400 nm of the reaction product solution was 0.3 or more.
[0020]
【The invention's effect】
According to the present invention, a high-quality phenolic compound can be efficiently produced from cumene hydroperoxides. In addition, the present invention can be scaled up to an industrial mass production scale by installing a plurality of microtubular reaction channels in parallel.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a reaction apparatus used in the present invention.
[Explanation of symbols]
1A CHP / phenol solution supply pipe 1B Sulfuric acid / phenol solution supply pipe 1C Ammonia water supply pipe 2A to C Syringe pump 3A CHP / phenol solution introduction pipe 3B Sulfuric acid / phenol solution introduction pipe 3C Ammonia water introduction pipe 4 Junction 5 Microtubular reaction Channel 6 Sample bottle

Claims (10)

Using a flow reactor with a microtubular reaction channel as a reactor, supplying sulfuric acid dissolved in a compatibilizer to the reactor, and decomposing cumene hydroperoxides with sulfuric acid in the microtubular reaction channel A method for producing a phenol compound and acetone. The process according to claim 1, characterized in that cumene hydroperoxides are mixed with a compatibilizer and fed to the reactor. The method according to claim 2, wherein cumene hydroperoxides and sulfuric acid dissolved in a compatibilizing agent are directly supplied to the microtubular reaction channel. The method according to any one of claims 1 to 3, wherein sulfuric acid is dissolved in a compatibilizing agent so as to be 100 to 10,000 ppm and fed to the reactor. The cumene hydroperoxides are fed to the reactor so that the concentration of cumene hydroperoxides in the total feed fed to the reactor is 5 to 30% by weight. The method of crab. The sulfuric acid is dissolved in a compatibilizing agent so that the concentration of sulfuric acid in the total feed fed to the reactor is 50 to 500 ppm by weight, and then fed to the reactor. A method according to any one of the above. The method according to any one of claims 1 to 6, wherein the compatibilizing agent is a phenol compound. Cumene hydroperoxides and phenolic compounds are fed into the reactor such that the compatibilizing agent is a phenolic compound and the ratio of phenolic compounds to cumene hydroperoxides in the total feed fed to the reactor is greater than 1. The method according to claim 1, wherein the method is provided. The method according to any one of claims 1 to 8, wherein an equivalent diameter of the microtubular reaction channel is 10 to 30,000 µm. A flow-type reactor having a microtubular reaction channel is used as a reactor, and sulfuric acid dissolved in a compatibilizer is supplied to the reactor, and cumene hydroperoxide is decomposed with sulfuric acid in the microtubular reaction channel. A process for producing phenol and acetone.

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