JPS58162540A - Production of alpha-aryl-tertiary-alcohol - Google Patents

Abstract

PURPOSE:An oxygen-containing gas is brought into contact with a reaction system containing an aryldialkylmethane in the presence of a catalyst of a transition metal compound and an aqueous alkali of a specific concentration to produce the titled compound efficiently in high selectivity and yield. CONSTITUTION:A transition metal compound as a catalyst and an aqueous caustic alkali of 20-35% concentration are added to the reaction system containing an aryldialkylmethane of the formula (X is H, halogen, alkyl, alkoxy; n is 1-3; R<1> and R<2> are lower alkyl such as methyl) such as cumene or chlorocumene and a gas containing oxygen is brought into contact with the above mixture at 90-130 deg.C and normal pressure to effect oxidation, thus producing the objective compound. As a transition metal compound, is cited a salt of a metal that can be in 2 or more different stable valencies, such as a compound of Ni, Co, Fe, Cr, Ag, or V, preferably a naphthenate or acetate. USE:Synthetic intermediate of drugs and farm chemicals.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an α-aryl tertiary alcohol, and more specifically, the present invention relates to a method for producing an α-aryl tertiary alcohol, and more specifically, a reaction system containing an aryl dialkylmethane is added with an oxygen-containing gas in the presence of a specific catalyst and a caustic alkali aqueous solution at a certain concentration. This invention relates to a method for producing α-aryl tertiary alcohol from aryldialkylmethane in high yield by supplying α-aryl tertiary alcohol.

It has been widely known that α-aryl tertiary alcohols can be produced by oxidizing alkylmethanes. For example, (1) Fuel Road Journal 3. !
;, for 37g to 52, a method using sodium carbonate and a transition metal compound as a catalyst, (2) Japanese Patent Publication No. 39-79
Publication No. 333 discloses a method using caustic alkali and manganese salts as catalysts, and (3) Japanese Patent Publication No. 39-2/217λ discloses a method using extremely high concentration of caustic soda. α-aryl tertiary alcohols have been produced from aryldialkylmethanes by.

However, methods (1) to (3) above have drawbacks such as low selectivity, production of large amounts of by-products such as benzophenone and cumyl hydroperoxide, or low conversion of raw material compounds. However, the actual results were not satisfactory.

Therefore, the inventors of the present invention have conducted extensive research in order to overcome the drawbacks of the above-mentioned conventional techniques and to develop a method for producing α-aryl tertiary alcohols with a high conversion rate and with few side reactions. As a result, they discovered that the reaction can proceed efficiently by using a transition metal compound as a catalyst and bringing it into contact with a caustic alkali aqueous solution of a certain concentration, and have completed the present invention.

That is, the present invention provides a method for producing an α-aryl tertiary alcohol by supplying a gas containing oxygen to a reaction system containing aryldialkylmethane in the presence of an aqueous alkali solution, in which a transition metal compound is added to the reaction system. The present invention also provides a method for producing an α-aryl tertiary alcohol, characterized in that a caustic alkali aqueous solution having a concentration of 20 to 35% is used as the alkaline aqueous solution.

The raw material compound used in the method of the present invention is an aryldialkylmethane, and this compound is represented by R''. Here, X in the formula is a hydrogen atom, a chlorine atom, a bromine atom, etc., or a methyl group, Alkyl groups such as ethyl groups, methoxyl groups.

It is an alkoxyl group such as an ethoxyl group, and n is box, 3
is an integer. Also R1. R2 is a lower alkyl group such as a methyl group, an ethyl group, or a zologyl group, respectively. Specifically, cumene, 〇-chlorcumene, p
-Chlorcumene, secondary-/''thylbenzene, 0-chloro-secondary zothylbenzene, p-chloro-IN282
Examples include butylbenzene.

Catalysts used in the method of the present invention include transition metal compounds,
In other words, salts of metals that can have two or more stable valences can be mentioned. Specific examples include compounds of metals such as manganese, nickel, cobalt, iron, chromium, silver, and vanadium, particularly acetates, higher fatty acid salts, naphthenates, and benzene carboxylates. The amount of the transition metal compound added as a catalyst is not particularly limited, but is usually θ, θ/~/θ weight ratio relative to the raw material compound aryldialkylmethane, preferably 0.7
~3 weight staff.

Further, in the method of the present invention, it is necessary to make an aqueous caustic alkali solution exist in the reaction system and bring it into contact with the arylsialkylmethane, which is a raw material compound.

Here, the aqueous alkali solution used is a caustic alkali, that is, an aqueous solution of sodium hydroxide or potassium hydroxide. Aqueous solutions of sodium carbonate, calcium hydroxide, etc. cannot achieve the purpose. Furthermore, this caustic aqueous solution has a concentration of 20 to 35%, preferably 2S
~Three-way joints are used. If the concentration is less than the λθ coefficient, the reaction rate will be low and the conversion rate of the raw material compound will be low, which is not preferable. On the other hand, if it exceeds 3S%, the conversion rate of the raw material compound similarly decreases, which is not preferable.

The amount of this caustic aqueous solution to be used is not particularly limited and may be determined as appropriate depending on various conditions, but it is usually ~200F, preferably S~50? It is.

In the method of the present invention, the target α-aryl tertiary alcohol is produced by oxidizing aryldialkylmethane by supplying an oxygen-containing gas, such as air or oxygen, to the above-mentioned reaction system. be. Here, the supply rate of the gas containing oxygen varies depending on various conditions such as the reaction temperature and the type of raw materials, and cannot be unambiguously determined, but it is usually 70 to 100 mL per ml of raw material compound and 70 to 100 mL of oxygen. It should be supplied at a ratio of . Further, this reaction is generally carried out at 50°C or higher, preferably at 90-/3θ°C. Furthermore, this reaction may be carried out under normal pressure or, if necessary, under increased pressure.

According to the method of the present invention such as slanting, a high conversion rate can be achieved without lowering the selectivity compared to the prior art. −
! Since there are almost no peroxides in the product,
Post-processing can be performed safely.

Therefore, the method of the present invention has extremely high utility value as it can efficiently produce α-aryl tertiary alcohols useful as synthetic intermediates for pharmaceuticals and agricultural chemicals.

Next, examples of the present invention will be shown.

Example / 700 ml of p-chlorcumene, 2 g of a 3Q% aqueous solution of caustic soda, and naphthene were placed in a θQml glass flask equipped with a stirrer driven by a motor, a gas inlet tube, a temperature meter, and a reflux condenser. Manganese acid 0.
The reaction was carried out for 6 hours at a reaction temperature of 100° C. by blowing oxygen into the reactor at a rate of 110 ml/11 min from the gas introduction tube. After the reaction, 30 ml of water was added and neutralized with a 6N aqueous hydrochloric acid solution, and the composition of the resulting organic layer was determined by liquid chromatography. As a result, p-chlorocumene, l3
wt%, p-chloro-α-cumyl alcohol l, 5
It was found that wt%.

3 in place of 30% caustic soda aqueous solution in Comparative Example/Example/
The reaction was carried out under the same conditions and treatment method as in Example, except that a 0% aqueous caustic soda solution was used. As a result, the composition of the obtained organic layer was p-chlorcumene 32.9
wt%, p-chloro-α-cumyl alcohol 3.3. /
It was wt%.

Example In Example/, 100 ml of cumene was used instead of p-chlorcumene, and cumene hydroperoxide (content: 3 wt%)/, 3
P was added, and the reaction was otherwise carried out under the same conditions as in Example. The composition of the obtained organic layer was α-cumyl alcohol 70%
wt%, and 1 gwt of Cumen.

Comparative Example In Example 3, the reaction was carried out under the same conditions as in Example 1, except that a 70% aqueous solution of caustic soda was used instead of a 30% aqueous solution of caustic soda. The composition of the obtained organic layer was 37 wt% of α-cumyl alcohol.

The cumene content was 33 wt%.

Claims (1)

[Claims] 1. A method for producing an α-aryl tertiary alcohol by supplying a gas containing oxygen to a reaction system containing aryldialkylmethane in the presence of an aqueous alkali solution, wherein a transition metal compound is added to the reaction system. 1. A method for producing an α-° aryl tertiary alcohol, which is characterized in that a caustic alkali aqueous solution having a concentration of 20 to 33% is used as the alkaline aqueous solution. 2. The method according to claim 1, wherein the transition metal compound is a compound of seven or more metals selected from the group consisting of manganese, nickel, cobalt, iron, chromium, silver, and vanadium.