JPH0357886B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is represented by general formula (A) (In the formula, R ₁ and R ₂ are H and CH ₃ groups, R ₃ and R ₄ are H,
_C1 - _C3 alkyl group,

【formula】 【formula】

【formula】

[Formula] −COCH ₃

[Formula] -COOH represents a carboxylic acid ester group. ) Decomposed hydroperoxide and expressed by general formula (B) (In the formula, R ₁ is H, CH ₃ group, R ₃ and R ₄ are H, C ₁ -
_C3 alkyl group,

【formula】 【formula】

【formula】

[Formula] −COCH ₃

[Formula] -COOH represents a carboxylic acid ester group. ) This relates to an industrially very advantageous manufacturing method for aromatic carbonyl compounds. Conventional methods for synthesizing carbonyl compounds by decomposing hydroperoxides include (1) a method by thermal decomposition in the coexistence of an aqueous alkaline solution; (2) Decomposition method using potassium ferrocyanide. (Reference: JACS, 75 4268 (1953)) (3) Decomposition method using ferrous salt (Fe ⁺⁺ ) (Reference: J.Org.chem., 15 763 (1950), etc.) Although it is known, in method (1), a large amount of alcohol compound is simultaneously produced and it is not possible to obtain a carbonyl compound in a good yield. According to the example cited in the cited literature, method (2) has a very high yield of acetophenone from kyumene hydroperoxide, but because the reaction is almost stoichiometric, it uses a large amount of expensive potassium ferrocyanide. It is not necessarily an advantageous method from an industrial perspective. Method (3) has been used in many studies and literature examples for a long time. For example, in the cited literature, 71% of acetophenone is decomposed by decomposing quiumene hydroperoxide with ferrous salt (Fe ⁺⁺ ). The yield is obtained. However, these methods using ferrous salts (Fe ⁺⁺ ) generally require a large amount of ferrous salt and have low yields, and cannot necessarily be said to be advantageous from an industrial standpoint. As a result of intensive studies in view of the current situation, the present inventors have found that by decomposing hydroperoxides in an inert gas atmosphere in the presence of an aqueous layer containing iron salts, copper salts, and acids, a significantly higher yield can be achieved. The present invention was completed by discovering that aromatic carbonyl compounds can be obtained efficiently with a fast decomposition rate. That is,
The present invention is represented by general formula (A) (In the formula, R ₁ and R ₂ are H, CH ₃ is R ₃ , R ₄ is H, C ₁
~ _C3 alkyl group,

【formula】 【formula】

【formula】

[Formula] −COCH ₃ ,

[Formula] -COOH represents a carboxylic acid ester group. ) Decomposed hydroperoxide and expressed by general formula (B) (In the formula, R ₁ is H, CH ₃ group, R ₃ and R ₄ are H, C ₁ -
_C3 alkyl group,

【formula】 【formula】

【formula】

[Formula] −COCH ₃ ,

[Formula] -COOH represents a carboxylic acid ester group. ) Production of an aromatic carbonyl compound, which is characterized in that the hydroperoxide is decomposed in an inert gas atmosphere in the presence of an aqueous layer containing an iron salt, a copper salt, and an acid. It's a method. A specific example of the hydroperoxide represented by the general formula (A) in the present invention is isopropylnaphthalene hydroperoxide. A specific example of the aromatic carbonyl compound represented by the general formula (B) is acetylnaphthalene. Although there are no particular limitations on the production of hydroperoxides represented by general formula (A), industrially common production methods include general formula (C). (In the formula, R ₁ and R ₂ are H and CH ₃ groups, R ₃ and R ₄ are H,
_C1 - _C3 alkyl group,

【formula】 【formula】

【formula】

[Formula] −COCH ₃ ,

[Formula] -COOH represents a carboxylic acid ester group. ) can be easily obtained by air oxidation. The present invention is carried out under an atmosphere of an inert gas such as nitrogen or helium. Air or oxygen atmosphere is not preferred because the metal salt is oxidized, the reaction rate is reduced, and the yield of the aromatic carbonyl compound is reduced. In the present invention, the coexistence of iron salt and copper salt is essential. If only iron salts are used, the yield of aromatic carbonyl compounds is low, and the decomposition of hydroperoxides is very fast at the beginning of the reaction, but in order to increase the decomposition rate of hydroperoxides, a long reaction time is required. However, there are disadvantages in that it requires a large amount of iron salt or requires a large amount of iron salt. Under these circumstances, the present inventors have found that, under specific conditions, the presence of a copper salt together with an iron salt significantly improves the reaction rate.As a result, the amount of iron salt used can be significantly reduced, and aromatic carbonyl compounds It was also found that the yield of The amount of iron salt and copper salt is 0.001 to 1 per mole of hydroperoxide group of the hydroperoxide.
moles preferably 0.005 to 0.5 moles of iron salts and iron salts 1
0.01 to 4 mol, preferably 0.05 to 3 mol, of copper salt is used per mole. If the amount of iron salt used is less than 0.001 mol per 1 mol of hydroperoxide group, the reaction rate is slow;
This is disadvantageous because a large amount of alcohols are produced due to side reactions, and although the reaction rate becomes faster when more than 1 mole is used, side reactions result in the production of phenols or heavy components, which is not a good idea.
If the amount of copper salt used is less than 0.01 mol per mol of iron salt, there will be no coexistence effect and the yield of the aromatic carbonyl compound will not improve, and if it is more than 4 mol, the yield will be improved to some extent. The catalyst cost for producing aromatic carbonyl compounds increases, and in the end,
This is not desirable as it is disadvantageous. Further, the present invention is characterized in that the iron salt is a ferrous salt and/or
Or, the ferric salt and copper salt are cuprous salts and/or
The point is that a cupric salt is used. Conventionally, only ferrous salts have been used, but the present inventors have found that aromatic carbonyl compounds can be obtained in good yield even with ferric salts in the presence of copper salts. Iron salts used in _the present invention include iron sulfate, iron hydrochloride, iron nitrate, iron citrate, iron lactate, iron oxalate, iron oxide, iron hydroxide (such as _Fe2O3 ), iron hydroxide (such as Fe(OH) ₃ ) etc. are examples. Examples of copper salts include copper sulfate, copper chloride, copper nitrate, copper acetate, copper oxide (for example, CuO), and copper hydroxide (for example, Cu(OH) ₂ ). Particularly preferably, the iron salt is ferrous sulfate and/or ferric sulfate.
Iron is used in combination with copper sulfate as a copper salt. Acid has the effect of suppressing sludge formation,
Mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, etc. are used, and sulfuric acid is particularly preferably used. In the present invention, the hydroperoxide may be subjected to the reaction as it is, but in order to allow the reaction to proceed smoothly, it is more preferable to use an appropriate organic solvent and provide the hydroperoxide as an organic solvent layer containing the hydroperoxide. Examples of organic solvents include benzene,
Toluene, xylene and methyl isobutyl ketone are used. The mixing ratio of the organic layer containing hydroperoxide and the aqueous layer containing iron salts, copper salts, and acids is 100% by weight of the organic layer.
The amount of water layer per part is adjusted to 10 parts or more, preferably 20 parts or more. If the proportion of the aqueous layer is less than 10 parts, the reaction rate will be slow, and side reactions will increase the production of phenols or heavy components, which is not preferable. Furthermore, in the present invention, the aqueous layer containing iron salt, copper salt, and acid can be reused by separating oil and water after the reaction is completed, which is one of the characteristics that is significantly different from conventional ferrous salts only. It is. The reaction temperature is usually 30-100℃, preferably 40-90℃
A range of °C is selected. If the reaction temperature is less than 30°C, the reaction rate is slow, and if the reaction temperature exceeds 100°C, there will be many side reactions, which is disadvantageous. On the other hand, the reaction pressure is usually carried out under atmospheric pressure, but it is also possible to carry out the reaction under reduced pressure. The reaction can be carried out either batchwise or continuously. After completion of the reaction, the compound represented by general formula (B) is precipitated as a solid from the reaction mixture, or is recovered as an oil layer after oil and water separation. If higher purity is required, it can be purified by conventional methods such as recrystallization or distillation. When an organic solvent is used in the reaction, after the oil and water are separated, the organic solvent is removed by a conventional method such as distillation, and the bottom liquid can be recovered by further distillation under reduced pressure. The present invention will be explained in detail below with reference to Examples, but the scope of the present invention is not limited by these. Example 1 1000 g of methyl isobutyl ketone solution (containing 0.99 mol of hydroperoxide group) containing 20 wt% β-isopropylnaphthalene hydroperoxide was placed in a 5-separable flask, and the mixture was heated under nitrogen flow.
The temperature was raised to 80°C. After the internal temperature of the flask reached 80℃, add 13.7 g of hydrated ferrous sulfate (Fe ⁺⁺ ; containing 0.049 mole) and copper sulfate (Cu ⁺⁺ ; containing 0.049 mole) using the dropping funnel.
7.9 g of concentrated sulfuric acid and 1000 g of an aqueous solution containing 2.5 g of concentrated sulfuric acid were added thereto, and the reaction was carried out at 80°C. After 3 hours of reaction, the residual concentration of hydroperoxide was 0.1 wt% or less, and the reaction was substantially complete. G.C.
Analysis results showed that the yield of β-acetylnaphthalene was 90%.
It was hot.

Claims (1)

[Claims] 1 Represented by general formula (A) (In the formula, R ₁ and R ₂ are H and CH ₃ groups, R ₃ and R ₄ are H,
C ₁ -C ₃ alkyl group, [Formula] [Formula] [Formula] [Formula] -COCH ₃ [Formula] -COOH, represents a carboxylic acid ester group. ) Decomposed hydroperoxide and expressed by general formula (B) (In the formula, R ₁ is H, CH ₃ group, R ₃ and R ₄ are H, C ₁ -
C ₃ alkyl group, [Formula] [Formula] [Formula] [Formula] -COCH ₃ [Formula] -COOH, represents a carboxylic acid ester group. ) Production of an aromatic carbonyl compound, which comprises decomposing the hydroperoxide in an inert gas atmosphere in the presence of an aqueous layer containing an iron salt, a copper salt, and an acid. Method. 2. The method according to claim 1, wherein the iron salt and copper salt are water-soluble salts. 3. In the decomposition of the hydroperoxide, the iron salt used is in an amount of 0.001 to 1 mol per mol of hydroperoxide group of the hydroperoxide,
2. The method according to claim 1, wherein the copper salt is used in an amount of 0.01 to 4 moles per mole of iron salt. 4. The method according to claim 2, wherein the iron salt and copper salt are sulfates. 5. The method according to claim 1, characterized in that the hydroperoxide is used as a solution in an organic solvent. 6. The method according to claim 5, wherein the weight of the aqueous layer containing the iron salt, copper salt, and acid is 10 times or more per 100 parts of the weight of the organic solvent layer containing the hydroperoxide.