JPS61246160A - Production of diaryl peroxide - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a rubber crosslinking agent, etc., in high yield by the one-stage reaction, by reducing an aryl hydroperoxide in the presence of a Pd catalyst containing TiO2 as a carrier at a specific temperature. CONSTITUTION:An aryl hydroperoxide is reduced in the presence of a Pd catalyst containing TiO2 as a carrier, e.g. supporting 0.5-10wt%, preferably 0.5-5wt% Pd, at 60-130 deg.C temperature to afford the aimed diaryl peroxide, e.g. a dicumyl peroxide compound expressed by the formula (R<1> and R<2> are H or 1-3C alkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the production of T
The present invention relates to a method for producing a diaryl peroxide compound represented by formula (1) by carrying out a reduction reaction using hydrogen gas in the presence of a Pd catalyst using i02 as a carrier.

BACKGROUND OF THE INVENTION Diaryl peroxides, particularly dicumyl peroxides, are useful as crosslinking agents and decomposition agents for rubbers and plastics, initiators for polymerization reactions, initiators for oxidation reactions, and the like.

As a method for producing diaryl peroxides, aromatic (
A method of condensing an aryl hydroperoxide with a corresponding aromatic alcohol, a method of reacting an aryl hydroperoxide with a corresponding aromatic olefin, and the like are known.

The method for producing the aromatic alcohol described above involves a reaction in which aryl hydroperoxide is reduced with an aqueous sodium sulfite solution.
Alternatively, a reaction in which reduction is performed using hydrogen gas in the presence of a Pd-containing catalyst is known.

Known methods for producing the aromatic olefin include dehydration of aromatic alcohols and dehydrogenation of aromatic alkyl compounds that are raw materials for producing aryl hydroperoxides.

However, since all of these production methods involve many reaction steps, the production cost may be high depending on the method. In addition, in the condensation reaction or reduction reaction using an aqueous sodium sulfite solution, equimolar amounts of the catalyst and the aryl peroxide are required, which increases the cost of the catalyst and increases the amount of wastewater discharged during production with a high COD concentration. It's a win.

The production of aromatic olefins by dehydrogenation of aromatic alkyl compounds requires a reaction temperature of 500° C. or higher, and requires two distillation columns for separation and purification.

Problems to be Solved by the Invention Therefore, the present inventors conducted intensive research in order to overcome these drawbacks of the conventional method. Although it is said that most of the reaction products are aromatic alcohols (Japanese Patent Application Laid-Open No. 18843/1984),
The inventors have unexpectedly discovered that diaryl peroxides can be directly obtained by selecting a catalyst carrier, leading to the present invention.

Means for solving the problem, namely, the present invention provides aryl hydroperoxide with Ti
O2 (anatase type is preferable, its specific surface area is 20~
100m'/g, preferably 35-89m'/gs)
The present invention relates to a method for producing diaryl peroxides, which is characterized by reducing the diaryl peroxides with hydrogen gas at a temperature of 60 to 130° C. in the presence of a Pd catalyst having Pd as a carrier.

Action The aryl hydroperoxides used in the method of the present invention include α-phenylethyl hydroperoxide,
Aryl hydroperoxides having 8 or more carbon atoms are preferred, such as cumene hydroperoxide, cymene hydroperoxide, and diisopropylbenzene monohydroperoxide. Since aryl hydroperoxide having 7 carbon atoms is rapidly decomposed in the presence of a catalyst, diaryl hydroperoxide is not produced.

Diaryl peroxides obtained by the method of the present invention include, for example, dicumyl peroxide, dicumyl peroxide, cumyl cymyl peroxide, bis(
p-ethylsimyl) peroxide.

The raw material aryl hydroperoxide may be used after being dissolved in a suitable solvent.

Aryl hydroperoxides are generally obtained by oxidizing the corresponding aromatic hydrocarbons, and the oxidation reaction yields aryl hydroperoxides at a reaction rate of 5 to 30%, which is then concentrated to produce a high concentration of aromatic hydrocarbons. You're getting hydroperoxide. The oxidation reaction product can be used as such or in highly concentrated concentrated amounts.

The concentration of aryl hydroperoxide is 30-90 wt%
is preferred. If it is lower than the lower limit, not only will the yield of diaryl peroxide decrease, but also the amount of the corresponding aromatic alcohol produced will increase. Furthermore, this leads to an increase in the amount of solvent that must be removed during product purification, which is economically disadvantageous.

The catalyst used in the present invention is a Pd catalyst using TiO2 as a carrier.
d amount (wt%) is 0.5 to 10 wt%, preferably 0.5 to 10 wt%.
It is 5 to 5 wt%. If it is less than 0.1%, the reaction will be extremely slow, resulting in a decrease in the productivity of diaryl peroxide. If it exceeds 10%, the amount of corresponding aromatic alcohol produced will increase, resulting in a decrease in the yield of diaryl peroxide. .

As the reactor, either a suspension type or a fixed bed type can be used.

The reaction temperature is usually 60°C to 130°C. 100 more
℃~120℃ is desirable. A temperature lower than 60° C. is not preferable because the reaction progresses slowly and the proportion of corresponding aromatic alcohol produced increases.

If the temperature is higher than 130° C., an increase in by-products due to self-decomposition of the aryl hydroperoxide may be observed, which is not preferable from the viewpoint of safety due to self-decomposition.

The amount of hydrogen supplied is generally 1 to 10 times the chemical equivalent of the aromatic hydroperoxide.

The present invention will be explained below with reference to Examples, in which % indicates weight %, and compositional analysis was performed for aryl hydroperoxides by iodometry and for dicumyl peroxides by liquid phase chromatography. Ta.

Example 1 In a four-bottle flask with a volume of 501) d equipped with a hydrogen blowing nozzle, a condenser with a water collection trap, and a stirrer, 80% of cumene hydroperoxide, 8.6% of dimethylphenyl carbinol, and 1.2% of acetophenone were added. %, cumene 12
．． 300 g of 2% solution was added. Powder T i 02 to 2
% Pd-supported catalyst (manufactured by Nippon Engelhard)
1.5 g was added, the temperature was raised to 100°C using an oil bath, and the temperature was maintained at 100°C thereafter. Stir 1300
An RP layer is formed, hydrogen gas is supplied at 75 Ni/hr, and the reaction is carried out at normal pressure.

As a result of the reaction for 5.3 hours, the entire amount of cumene wg peroxide was consumed. The hydrogen gas supply was immediately stopped and the temperature was lowered. After cooling to room temperature, the catalyst was filtered off to obtain a reaction product.

As a result of analysis, the composition of the reaction product was 0.1% or less of cumene hydroperoxide and 20% of dimethylphenyl carbinol.
%, acetophenone 2.5%, dicumyl peroxide 6
5.5% and cumene 12%.

Example 2 An experiment was conducted using the method of Example 1 except that the reaction temperature was changed to 120°C.

After 1 hour of reaction, the total amount of cumene hydroperoxide was consumed. After the reaction was stopped, the catalyst was filtered off to obtain a reaction product.

As a result of analysis, the composition of the reaction product was 0.1% or less of cumene hydroperoxide, 7.0% of dimethylphenyl carbinol.
3%, acetophenone 7.4%, dicumyl peroxide 68.1%, α-methylstyrene 2.3%, cumene 12
%, and others 1.9%.

Example 3 The same procedure as in Example 1 was repeated except that the reaction temperature was 130°C and the raw material was changed to cymene hydroperoxide. As a result, dicumyl peroxide was 80.3%, cymene hydroperoxide was 0.3% or less, and dimethyltritrioxide was 80.3%. The results were 4.3% carbinol, 17.4% cymene, 5.2% isopropenyltoluene, and 12.5% tolyl methyl ketone.

Comparative Example 1 In the method of Example 1, the catalyst was added to powder α-M203.
．． The reaction was carried out at 100° C. using a catalyst (manufactured by Nippon Engelhardt Co., Ltd.) on which 0% Pd was supported.

Analysis of the reaction product after 5.5 hours of reaction revealed that the composition of the product was 0.2% cumene hydroperoxide, 75.6% dimethylphenyl carbinol, and 3.5% acetophenone.
9%, dicumyl peroxide 7.8%, cumene 12.5
%Met.

Comparative Example 2 In the method of Example 1, a reaction was carried out at 100° C. using a catalyst (manufactured by Nippon Engelhardt Co., Ltd.) in which 2% Pd was supported on carbon beads.

Analysis of the reaction product after 8 hours of reaction revealed that the composition of the product was 3.8% cumene hydroperoxide, 78.2% dimethylphenyl carbinol, and 2.8% acetophenone.
, dicumyl peroxide 4.3% and cumene 12.8%
Met.

Effects of the Invention Conventionally, for example, diaryl peroxides were obtained by hydrogenating half of the aryl hydroperoxide to convert it into aryl alcohol, and dehydrating and condensing this with the aryl hydroperoxide, but according to the present method, TiO
By carrying out hydrogenation using Pd supported on 2, diaryl peroxides can be obtained in a high yield in a one-step reaction.

Claims (1)

[Claims] 1. A method for producing diaryl peroxides, which comprises subjecting aryl hydroperoxide to a reduction reaction with hydrogen gas at a temperature of 60°C to 130°C in the presence of a Pd catalyst using TiO_2 as a carrier. 2. The method according to claim 1, wherein the reaction temperature is 100°C to 120°C. 3. Diaryl peroxides have the formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (However, in the formula, R^1 and R^2 represent hydrogen or an alkyl group having 1 to 3 carbon atoms. ) The method according to claim 1, wherein the dicumyl peroxide compound is a dicumyl peroxide compound represented by: