JPS5978138A - Preparation of aromatic carbonyl compound - Google Patents

Abstract

PURPOSE:To obtain an aromatic carbonyl compound efficiently in remarkably high yield, by decomposing a hydroperoxide in the presence of an aqueous layer containing an iron salt, a copper salt and an acid in an atmosphere of an inert gas. CONSTITUTION:A hydroperoxide of formula I [R1 and R2 are H or CH3; R3 and R4 are H, alkyl, -C(CH3)2OH, -COCH3 or COOH, etc.] or formula II is decomposed to give an aromatic carbonyl compound of formula III or IV. In the process, the decomposition reaction is carried out in the presence of an aqueous layer containing an iron salt, copper salt (preferably both being sulfates) and an acid in a solution of the above-mentioned hydroperoxide in an organic solvent, e.g. methyl isobutyl ketone, to give the aimed aromatic carbonyl compound. The molar amounts of the salts are preferably as follows; 0.001-1mol, based on 1mol hydroperoxide group in the hydroperoxide, iron salt and 0.01-4mol, based on 1mol iron salt, copper salt. The amount of the aqueous layer containing the iron salt, copper salt and acid is preferably 10pts.wt. or more based on 100pts.wt. organic solvent layer containing the hydroperoxide.

Description

[Detailed description of the invention] The present invention is represented by the general formula (In the formula, R1, 几2 are) (, OH3 group, R3.

R4 represents H, a C1-03 alkyl group, -0OOH, a carboxylic acid ester group. ) Hydroperoxide or (5) represented by the general formula-2 (wherein R,, R2 is l(, OH3 group, 5R31R4 is H, 01-C3 alkyl group.

-〇〇OH, indicates a carboxylic acid ester group. ) The hydroperoxide is decomposed to form a compound of the general formula (Bl-1 (wherein, R1 represents an OHa group, R3 and R4 represent an alkyl group of H1C1 to C3, and (6) -0OOH represents a carboxylic acid ester group). ) or the general formula (4 represented by Bl-2 (wherein, R1 is H, OHa group, 几3.R4 is H9 -
Indicates a C3 alkyl group, 10OOH, and a carboxylic acid ester group. ) This relates to an industrially very advantageous method for preparing 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 alkali solution;

(2) Decomposition method using potassium ferrocyanide.

(References: , LA, O, S, , 754268 (1
95B) ) (3) Decomposition method using ferrous salt (pe←) (Reference; J, Org, chem, 15
76B (1950), etc.), but in the method (1), a large amount of alcohol compound is simultaneously produced, making it impossible to obtain a carbonyl compound in a good yield.

According to the examples cited in the cited literature, method (2) has a very high yield of acetophenone from cumene hydroperoxide, but because the reaction is almost stoichiometric, it is necessary to use a large amount of expensive potassium ferrocyanide. Therefore, it cannot necessarily be said to be an advantageous method from an industrial perspective.

Regarding method (3), there have been many research studies and literature examples for a long time. It has gained. However, these ferrous salts (
The method using Fe++) generally requires a large amount of Fe++ and has a low yield, and cannot necessarily be said to be an advantageous method 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 provides the general formula ((9) represented by Al-1) (wherein, Bl, B2 +, tH, OHs groups are
, R4 represents H, an alkyl group of 01-Os, and -0OOH, a carboxylic acid ester group. ) hydroperoxide or general formula (1 (lO) represented by Al-2 (wherein, R1, R2 are H, OHa group is Ra, R4 is H, Or-C3 alkyl group, -0OOH, carboxylic acid ester) ) The hydroperoxide is decomposed to form the general formula (Bl-1 1 3 (wherein 1 is H, OH3 group, R3 and R4 are H2C1
~03 alkyl group, 10OOH, carboxylic acid ester group. )1 (In the formula, R1 is H, OH3 group, 几3.R4 is H2OH
, 03 alkyl group, 10OOH, 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.

Specific examples of the hydroperoxide represented by the general formula (Al-1 or Al-2) in the present invention include cumene hydroperoxide, cymene hydroperoxide, diisopropylbenzene dihydroperoxide, ethylcumene hydroperoxide, and diisopropylbenzene monohydroperoxide. , diethylbenzene monohydroberoxide,
(2-Hydroxy-2-propyl)-cumene hydroperoxide, isopropenylcumene hydroperoxide, ethylbenzene-hydroperoxide, hydroxyethylethylbenzene hydroperoxide, acetylcumene hydroperoxide, triisopropylbenzene trihydroperoxide, cumic acid methyl hydroperoxide, Examples include isopropylnaphthalene hydroperoxide.

Specific examples of the aromatic carbonyl compound represented by the general formula (Bl-1 or (Bl-2) are acetophenone, (1B) methylacetophenone, ethyl acetophenone, isopropylacetophenone, (2-hydroxy-2-propyl)-acetophenone, Examples include propenylacetophenone, hydroxyethylvinylacetophenone, diacetylbenzene, acetylcumene hydroperoxide triacetylbenzene, methyl acetylbenzoate, acetylnaphthalene, and the like.

Although there are no particular restrictions on the production of hydroperoxides represented by the general formula (C1-1), RI and C2 are H, O
H3 group, R3 and R4 are H* C1-03 alkyl groups, (14) -0OOH, carboxylic acid ester group. ) or the general formula (C1-2 (in the formula, FLI, R2 is H, OHs group, E3, R
4 represents H, an alkyl group of 01 to C3, and 10OOH, a carboxylic acid ester group. ) can be easily obtained by air oxidation.

Hydroperoxides may be provided as a mixture of two or more types.

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 low, and the yield of the aromatic carbonyl compound is low.

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 mol per mol of hydroperoxide group of the hydroperoxide, preferably 0.005 to 0.5 mol of iron salt and 0.01 to 4 mol per mol of iron salt. Preferably 0.05 to 8 mol of copper salt is used.

The amount of iron salt used is 0 per mole of hydroperoxide group.
．． If less than 0.001 mole is used, the reaction rate will be slow and a large amount of alcohol will be produced due to side reactions, which is disadvantageous.If more than 1 mole is used, the reaction rate will be faster, but the side reaction will cause the production of phenols or heavy alcohols. This is not a good idea as it will result in a lot of stress. The amount of copper salt used is per mole of iron salt,
If it is less than 0.01 mol, 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, but the catalyst cost when producing the aromatic carbonyl compound will be high. In the end, this is not preferable because it becomes disadvantageous.

A further feature of the present invention is that the iron salt is a ferrous salt and/or a ferric salt, and the copper salt is a cuprous salt and/or a cupric salt.

(17) 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 due to the coexistence of copper salts.

Examples of 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 Fe20a), iron hydroxide (such as Fe(OH)3
) etc. are exemplified.

Copper salts include copper sulfate, copper chloride, copper nitrate, copper acetate, steel oxide (e.g. CuO), copper hydroxide (e.g. 0u(OH)
)2) are exemplified. Particularly preferably, a combination of ferrous sulfate and/or ferric sulfate as the iron salt and copper sulfate as the copper salt is used.

The acid has the effect of suppressing the formation of sludge, and mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid 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 carry out the reaction smoothly, an appropriate organic solvent is used and the hydroperoxide is provided as an organic solvent layer containing human(18)roperoxide. It is more preferable. As the organic solvent, for example, benzene, toluene, xylene, methyl isobutyl ketone, or a compound represented by the general formula 101-1 or (C)-2 is used.

The mixing ratio of the organic layer containing hydroperoxide and the aqueous layer containing iron salt, copper salt, and acid is adjusted so that the aqueous layer is at least 10 parts, preferably at least 20 parts, per 100 parts by weight of the organic layer.

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. .

The reaction temperature is usually 30-100°C, preferably 40-90°C.
A range of °C is selected. When the reaction temperature is less than 30°C, the reaction rate is slow, and when the reaction temperature exceeds 100°C, side reactions increase, 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 the reaction, the compound represented by the general formula (Bl-1 or (Bl-2) is precipitated as a solid from the reaction mixture, or is recovered as an oil layer after oil and water separation. If a higher purity box is required, can be purified by a conventional method, such as recrystallization or distillation.If an organic solvent is used in the reaction, after oil and water separation, the organic solvent is removed by a conventional method such as distillation, and then the canister is purified. The liquid can be recovered by further vacuum distillation.

The present invention will be explained in detail below using examples, but the scope of the present invention is not limited by these examples.

Example-1 19.9 wt% m-(2
-Hydroxy-2-propyl)-cumene hydroperoxide-containing methyl isobutyl ketone solution at 100 OP
, (containing 1.32 moles of hydroperoxide groups) were charged, and the temperature was raised to 80° C. under nitrogen flow. Flask internal temperature is 80℃
After reaching ++, the hydrated ferrous sulfate is added to the dropping funnel.

(Contains 0.066 mol of Fe) 18.8F, 10.55' of copper sulfate (Ou''; includes 0.066 mol), and 1000F of an aqueous solution containing 3.3 mmol of concentrated sulfuric acid were added, and 80
The reaction was carried out at °C. After 3 hours of reaction, the residual concentration of hydroperoxide was Q, 1 wt % or less, and the reaction was substantially completed. As a result of Go analysis, the yield of m-(2-hydroxy-2-propyl)-acetophenone is:
It was 92%.

Examples 2 to 6 Using a solution of m-(2-hydroxy-2-propyl)-cumene hydroperoxide in methyl isobutyl ketone,
The reaction was carried out in exactly the same manner as in Example 1 (21) by varying the amount of ferrous sulfate per mole of hydroperoxide group and the amount of copper sulfate per mole of ferrous sulfate. The results are summarized in Table-1.

(22) Comparative Example-1 19.9 wt% m-(2-
100 OP of a methyl isobutyl ketone solution containing hydroxy-2-propyl)-cumene hydroperoxide (containing 1.32 moles of hydroperoxide groups) was charged, and the temperature was raised to 80° C. under nitrogen flow.

After the internal temperature of the flask reached 80°C, 188y-
and 1,000 ml of ferrous sulfate aqueous solution containing 33 ml of concentrated sulfuric acid
y was added and the reaction was carried out at 80°C. After 9 hours of reaction, the residual concentration of hydroperoxide was 0. It was less than IM amount%.

Results of gas chromatography analysis (hereinafter referred to as GC analysis)
The yield of -(2-hydroxy-2-propyl)-acetophenone was 68%.

Comparative Example-2 19.9 wt% m-(2-
A methyl isobutyl ketone solution containing hydroxy-2-propyl)-cumene hydroperoxide was mixed with 100 OP and hydrated ferric sulfate 9 B'l (Fe++'';
1,000 y of water containing 0.38 moles) was charged and the temperature was raised to 80° C. under nitrogen flow. Although the reaction was carried out at 80° C. for 9 hours, a considerable amount of hydroperoxide remained without being decomposed, and no substantial reaction occurred.

Example-7 Hydrous ferric sulfate was replaced with ferric sulfate hydrate
．． The reaction was carried out in the same manner as in Example 1 except that 5y (Fe++''; containing 0.066 mol) was used. When ferric sulfate was used, the decomposition rate of hydroperoxide was higher than that of ferric sulfate. Although it was slightly slower than iron, the residual concentration of hydroperoxide was 0.1 wt% after 4.5 hours of reaction.
It was below. m-(2-hydroxy-2-propyl)
-The yield of acetophenone was 87%.

Example-8 The water layer was reduced so that the ratio of the hydroperoxide methyl isobutyl ketone solution to the aqueous solution containing ferrous sulfate, copper sulfate, and acid was 2:1 by weight, and the water layer was reduced to 50 (1'). Except for the above, the procedure was exactly the same as in Example-1.

After 3.5 hours of reaction, the residual concentration of hydroperoxide was below Q, 1 wt%.

The yield of m-(2-hydroxy-2-propyl)-acetophenone was 86%.

Examples 9 to 12 The same method as in Example 1 was carried out using various hydroperoxides as shown in Table 2 instead of m-(2-hydroxy-2-propyl)-cumene hydroperoxide. The implementation conditions and results are summarized in Table 2.

(25) Example-13 The aqueous layer collected in Example-1 was recycled and used. The procedure was carried out in the same manner as in Example 1, and the methyl isobutyl ketone solution containing the raw material m-(2-hydroxy-2-propyl)-cumene hydroperoxide was freshly prepared each time.
Prepare 10002. In the recovered water layer, the amount of hydrated ferrous sulfate was 115 and the amount of copper sulfate was 1/lo of the amount charged in Example-1.
A new amount was added each time for the reaction. The reaction time is as long as the residual hydroperoxide concentration is 0.1! The duration was set to 3 hours so that fi was as follows.

As a result of 5 recycling experiments, the yield of m-(2-hydroxy-2-propyl)-acetophenone was 90% in all cases.
% or more, and it was possible to recycle the water layer.

(27 completed) 288-

Claims (6)

[Claims] (1) General formula (represented by Al-1 (in the formula, RI I R2 is H, OH3 group, R3゜R4
represents H, O, -C3 alkyl group, -0OOH, carboxylic acid ester group. ) hydroperoxide or represented by the general formula -2 (where l'L, , R2 is H, OH3 group is .R3.R4
represents H, an alkyl group of 0l-Os, and -0OOH, a carboxylic acid ester group. ) Hydroperoxide is decomposed to form the general formula (Kawa-1 (in the formula, 几1 is H
9CH3 group, R3 and R.4 represent H, Ol, ca alkyl group, -0OOH, carboxylic acid ester group. ) or the general formula (I represented by Bl-2
~C3 alkyl group, -〇〇OH, represents a carboxylic acid ester group. ) A method for producing an aromatic carbonyl compound, which comprises decomposing the hydroperoxide in an atmosphere of inert scum in the presence of an aqueous layer containing an F1 iron salt, a copper salt, and an acid. . (2) The method according to claim 1, wherein the iron salt and the copper salt are water-soluble salts. (3) In the decomposition of the hydroperoxide, the iron salt used is the hydroperoxide group 1 of the hydroperoxide.
The amount is 0.001 to 1 mole per mole, and the copper salt is the iron salt 1
2. A method according to claim 1, characterized in that the amount is from 0.01 to 4 mol per mol. (4) The method according to claim 2, wherein the iron salt and copper salt are sulfate groups. (5) The method according to claim 1, characterized in that the hydroperoxide is used as a solution in an organic solvent. (6) The weight of the aqueous layer containing iron salt, copper salt and acid is 10 parts per 100 parts of the weight of the organic solvent layer containing the hydroperoxide.
6. The method according to claim 5, wherein