JPS63215652A - Production of 3,3',5,5'-tetraalkyl-4,4'-diphenoquinone - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high yield, with easy separation process, by subjecting a 2,6-dialkylphenol to oxidative coupling in an aqueous solvent containing a specific surfactant in the presence of a copper compound and basic substance and neutralizing the coupling reaction product. CONSTITUTION:A 2,6-dialkylphenol is subjected to oxidative coupling reaction in an aqueous solvent containing a fatty acid metal salt as a surfactant using a copper compound as a catalyst in the presence of a basic compound at 50-100 deg.C, preferably about 80-100 deg.C. The pH of the reaction system is maintained to >=7 during the oxidative coupling reaction and the obtained reaction mixture is neutralized to pH5-7. The acid used in the neutralization is preferably sulfuric acid or hydrochloric acid. After neutralization, the objective compound obtained as granular small blocks is separated from the aqueous layer. The surfactant used in the above process is especially preferably sodium laurate.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the production of L3'+515'-tetraalkyl-4,4'-diphenoquinone by an oxidative coupling reaction using 2,6-dialkylphenol as a starting material. Regarding the method. According to the method of the invention, 3 * 3'; 5
T5'-tetraalkyldiphenoquinone can be easily separated and produced from the reaction mixture in high yield.

[Conventional technology]

The product obtained by oxidative coupling 5ti (formula (1) below) of alkylphenols is such that as the alkyl group of the alkylphenol starting material becomes bulkier, the amount of diphenoquinone produced increases. For butylphenol, L3' + L5 with a selectivity of 100
'-Tetra-tert-butyl-4°4'-diphenoquinone.

Therefore, in order to obtain alkylbiphenols, it is necessary to further reduce diphenoquinone, but when attempting to isolate diphenoquinone from the reaction mixture, the crude diphenoquinone obtained by the oxidative coupling reaction is fine particles, so - It is extremely difficult to isolate silverfish using methods such as centrifugation. Particularly when the reaction is carried out in an aqueous solvent containing a surfactant, the reaction mixture is obtained as a viscous slurry, making isolation even more difficult. For this reason, in JP-A-58-140034, the oxidative coupling reaction is carried out in an aqueous solvent that does not contain a surfactant.
In this method, pressurization with oxygen and high temperature are essential69, and in JP-A-61-200935, the oxidative coupling reaction is carried out in t-butanol, but the reaction solution is The disadvantage is that the conversion rate must be kept low because it becomes a viscous slurry.

[Problem that the invention seeks to solve]

On the other hand, in JP-A No. 51-43748, an oxidative coupling reaction is carried out in an aqueous solvent containing an alkyl sulfate metal salt by selecting conditions such that the main product is a biphenol. After that, the porosity sintered glass F
Although the product is isolated by filtration using a dowel, it is difficult to carry out this operation industrially.

Therefore, a method suitable for industrial implementation that can easily isolate diphenoquinone from a reaction solution containing diphenoquinone as a main component obtained by oxidative coupling reaction in an aqueous solvent containing a surfactant has been desired. No solution has yet been proposed regarding this point.

[Means for solving problems]

The present inventors conducted intensive studies to solve the above-mentioned drawbacks of the prior art, and as a result, arrived at the present invention.

That is, the present invention provides a reaction in which a fatty acid metal salt is used as a surfactant in a reaction in which 2,6-dialkylphenol is oxidatively coupled in an aqueous solvent containing a surfactant in the presence of a copper compound and a basic substance. , L3'*L5'-tetraalkyl-4,4', suitable for industrial processes, in which the diphenoquinone-based product can be easily separated from the aqueous layer by neutralizing the reaction mixture obtained. −
A method for producing diphenoquinone is provided.

The alkylphenols used in the method of the present invention are linear chains in which the 2,6-positions of the phenol nucleus are Cl-C12 or j4
2,6-dialkylphenols substituted with chain-bearing alkyl groups, preferably with secondary or tertiary alkyl groups.

Specifically, 2,6-diinpropylphenol 2.6
-di-tert-butylphenol, 2,6-di-tert-butylphenol, 2-methyl-6-tert-butylphenol, 2-
Examples include cyclohexyl-6-'t'' tesylphenol.

As the copper compound used as a catalyst, either a cupric compound or a cupric compound that provides copper ions in an aqueous solution can be used.

Typical copper compounds include the following.

(ll halides, such as chloride, bromide and iodide.

(2) A basic hydroxide represented by the following formula.

CuX-Cu0H or CuXz-Cu(OR)z (wherein X is chlorine, bromine, iodine or fluorine) (3) Carboxylate, such as acetate, benzoate, etc.

(4) Sulfate.

(5) Nitrates.

(6) Alkyl sulfates and aryl sulfates.

(7) Carbonate and CuC0s-Cu(OH)z, C
Basic carbonates such as uzCOx-Cu(OK).

(8) Hydroxide.

(9) Chlorates such as CuC1Os, Cu(C2Os)2.

The amount of the copper compound used is usually 160 to 0.1 mol % based on the alkylphenol, but is not strictly limited.

Although the reaction occurs even in this range or in a small amount, the reaction rate is slow and the yield is low. Further, even if a larger amount of copper compound is used, no particular effect can be obtained, which is economically undesirable.

In the method of the present invention, it is necessary to have a basic substance present in the reaction system in order to maintain the pH of the reaction system at 7 or more until the oxidative coupling reaction is completed.

As the basic substance, hydroxides, carbonates, bicarbonates, etc. of alkali metals or alkaline earth metals are used. Specific examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, #j1.1 lithium, potassium carbonate, and sodium bicarbonate.

In the method of the present invention: 1. The reaction is carried out in an aqueous medium containing a surfactant, and the surfactant used is one or a mixture of two or more fatty acid metal salts. The fatty acid metal salt used as a surfactant in the present invention is a compound that releases fatty acids and loses surfactant ability upon neutralization, or an alkali or alkaline earth metal salt of a linear or side chain fatty acid having 10 to 20 carbon atoms. Ruru with salt.

Specific examples include sodium, potassium, and lithium salts of lauric acid, myristic acid, balmitic acid, oleic acid, stearic acid, etc., but sodium laurate is used from the viewpoint of reactivity in oxidative coupling reaction. It is preferable.

The reaction is generally carried out by adding an alkylphenol, a copper compound, a basic substance, a surfactant, and water to a suitable reaction vessel, stirring, raising the temperature, and then adding oxygen or air at a specified temperature. The oxidative coupling reaction is carried out by introducing an oxygen-containing i gas such as

Further, the reaction temperature is in the range of 50 to 100C, but in consideration of the reaction rate, it is desirable to maintain it at about 80 to 100C. At temperatures lower than that, the reaction rate decreases, making it necessary to lengthen the reaction time.

In the method of the present invention, after the oxidative coupling reaction, a product containing diphenoquinone as a main component is separated from water by adding an acid to the resulting reaction mixture and adjusting the pH of the reaction solution to 7 or less. At this time, make the liquid strongly acidic (lower the pH).
However, there is no particular effect, and on the contrary, the amount of washing of the product with water increases, and the pH is preferably set to 5 to 7. Acids used to neutralize the reaction mixture include acids with a pKa of 4 or less, such as sulfur (pe
a-1, 92: Chemistry Handbook Basic Edition ■, Maruzen p944 (1
975), hereinafter the same), hydrochloric acid (pk'a-rich-7
), p-toluenesulfone ff (PI6t=3), phosphinic acid (pea -1,0), etc. are suitable, but among these, sulfuric acid and hydrochloric acid are particularly easily available and economically preferable.

〔Effect of the invention〕

According to the present invention, a fatty acid metal salt is selected as a surfactant, and after the reaction, the obtained reaction mixture is neutralized and the pH of the reaction solution is adjusted, whereby the extracted diphenoquinone becomes granular small agglomerates and is completely removed from the aqueous layer. This separation not only makes operations such as filtration or centrifugation significantly easier, but also allows water to be removed from the separated reaction solution or as needed, without using operations such as filtration or centrifugation. By adding an organic solvent that is insoluble or poorly soluble in water,
This is also the first time that it has become possible to more easily extract and recover +sts'-tetraalkyl-4,4'-diphenoquinone.

In addition, the discharged water contains extremely little amount of harmful organic substances such as unreacted raw materials and reaction products such as diphenoquinone.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.
The present invention is not limited to these examples.

Example 1. In a 1 ton 4-bottle flask with baffles, 2,6-tert-butylphenol lo y (0.49 mol) and sodium hydroxide 5. Add Or (o, la mol), sodium laurate 1.2 f (5.4 mol) and 270 ft of ion-exchanged water, attach a thermometer, gas introduction tube, stirring blade, and pressure gauge, and heat while stirring. When the temperature rose and the content temperature reached 75°C, acetic acid secondary steel o, z
A solution of sp (x, zs mmol) dissolved in 30 f of ion-exchanged water was quickly added, and oxygen (oxygen pressure 0.1 kl/c) was added.
While introducing d), stirring was continued to maintain the temperature of the reaction mixture at 80°C for 5 hours. The introduction of the element was stopped. While keeping this reaction mixture at 80°C, 97%
6.2 f of concentrated sulfuric acid was gradually added dropwise. At the end of the addition of concentrated sulfuric acid, the pH was approximately 6, and granular small lumps of reddish-brown diphenoquinone floated on the water and were completely separated. At this time, the aqueous layer was colorless and transparent.

To this, diethylbenzene (0: m: p: p: j% isomer ratio: s: 6: 3 o) was added to completely dissolve diphenoquinone, and a portion of the solution was collected and analyzed by gas chromatography. The conversion rate of raw material 2,6-di-tert-butylphenol was 95, J+3'+51
Almost no components other than 5'-tetra-tert-butyl-4,4'-diphenoquinone were observed, and the selectivity was 99% or more.

Example 2 The same procedure as in Example 1 was carried out except that Nonsal LN-1 (containing sodium laurate i60%) 2f manufactured by Nippon Oil & Fats Corporation, which is a commercially available soap, was used instead of sodium laurate. At the end of the reaction, the conversion rate of 2,6-di-tert-butylphenol was 95%, and the selectivity of diphenoquinone was 997o. Moreover, the aqueous layer after pH adjustment was colorless and transparent.

Example 3 2,6-ditert-butylphenol 53.39 (0.26 mol) and sodium hydroxide 2
．． 5 f (63 mmol), sodium stearate 0.3 t (1.0 mmol), steel acetate 0.25 f
(1.25 mlJ mol) and reacted at 80° C. for 8 hours. After stopping the reaction, adjust the pH of the reaction solution to 3.12 with 97% concentrated sulfuric acid.
When the temperature was reduced to about 6, a reddish-brown diphenoquinone mass and water separated. The aqueous layer was clear and colorless.

When diethylbenzene 150F was added to dissolve diphenoquinone and analysis was performed, the conversion rate of the raw material 2,6-di-tert-butylphenol was 75%, and the selectivity of diphenoquinone was 99%.

Example 1 was carried out in the same manner as in Example 1 except that Nonsal PN-11,5F, which is an industrial soap containing sodium valmitate as a main component, was used instead of sodium laurate. At the end of the reaction, the conversion rate of 2,6-di-tertiary puderphenol was 70%, and the selectivity of diphenoquinone was 99%. Further, the aqueous layer after adjusting the pH to 4 was clear and colorless.

Comparative Example 1 The reaction was carried out in the same manner as in Example 1, except that 0.3 f (1.1 mmol) of sodium laurate was used instead of sodium laurate in Example 1, and the reaction time was changed to 3.5 hours. Nine. After the reaction was completed, the pH of the reaction solution was adjusted to approximately 6 using concentrated sulfuric acid, but although the diphenoquinone lumps floated, the water layer remained brown and cloudy and the interface was not clear, making it difficult to completely separate the diphenoquinone. Met. When 300 f of diethylbenzene was added to this, most of the diphenoquinone was dissolved, but the interface remained unclear and the water layer remained cloudy. When a part of the organic layer was analyzed, the conversion rate of the raw material 2,6-di-tert-butylphenol was 93%, and the selectivity of diphenoquinone was 99%.

Comparative Example 2 The same procedure as in Comparative Example 1 was conducted except that 0.3 f (0.9 mmol) of sodium dodecylbenzene sulfate was used instead of sodium lauryl sulfate. The aqueous layer after pH adjustment was brown and turbid, and the interface was not removed.

Claims (1)

[Claims] In a reaction in which 2,6-dialkylphenol is oxidatively coupled in an aqueous solvent containing a surfactant in the presence of a copper compound and a basic substance, a fatty acid metal salt is used as the surfactant, and the resulting reaction mixture is 3,3',5,5'-tetraalkyl-4,4
′-Method for producing diphenoquinone.