JPS6317842A - Production of quinone - Google Patents

Abstract

PURPOSE:To obtain a quinone in high yield, by using methyl alcohol as a solvent and cupric chloride and an alkali metal chloride in specific concentrations present in the reaction system for reacting a phenolic compound with oxygen in a solvent in the presence of a copper salt. CONSTITUTION:A phenolic compound, particularly unsubstituted phenol is reacted with oxygen in the presence of cupric chloride in an amount of 0.002-0.167mol, preferably 0.050-0.140mol based on 1,000g methyl alcohol and an alkali metal chloride in an amount of 0.5-10mol, preferably 2.5-5mol based on the above-mentioned cupric chloride in methyl alcohol as a solvent under preferably >=30kg/cm<2> oxygen pressure to afford the aimed benzoquinone compound, particularly p-benzoquinone useful as an intermediate for hydroquinone (useful in photographic industry, etc.).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing quinones corresponding to phenols by oxidizing them with molecular oxygen. Parabenzoquinone, particularly parabenzoquinone without a substituent, can be hydrogenated to produce the corresponding hydroquinone, which is an industrially useful compound used in the photographic industry and the like.

[Conventional technology]

It is known to produce Quino 788, unsubstituted or substituted benzoquinone, by reacting phenols, unsubstituted or substituted phenols, with oxygen in the presence of a copper salt and in a solvent. However, according to conventionally known methods, the yield of quinones cannot be said to be sufficient. A method for producing the corresponding quinones by oxidation with oxygen gas in a solvent in the presence of halogen ions has been described, but the yield is low.

[Problem that the invention seeks to solve]

The present invention aims to improve the low yield of rosebenzoquinone by using a specific solvent and a specific catalyst compared to the conventional technique.

[Means for solving problems]

The present inventors solved the above problem by using methyl alcohol as a solvent and carrying out the reaction in the presence of specific concentrations of cupric chloride and alkali metal chlorides. That is, the present invention provides a method for producing quinones, i.e., unsubstituted benzoquinone or substituted benzoquinone, by reacting phenols, i.e., unsubstituted phenol or substituted phenol, with oxygen in the presence of a copper salt and in a solvent,
In methyl alcohol as a solvent, 0.002 to 0.167 cupric chloride per 1000 g of methyl alcohol
The method for producing quinones is characterized in that the reaction is carried out in the presence of 0.5 to 10 moles of alkali metal chloride Th per mole of cupric chloride.

The phenols used in the present invention, i.e. non-monocarbons (in the formula,
R2, R2, R3 and R4 may be the same or different, hydrogen, halogen, cyano, 1-12
alkyl or alkoxy containing from 6 to
unsubstituted or substituted phenyl or unsubstituted or substituted phenoxy group containing 16 carbon atoms), in particular as R3, R8, R1 and R9 hydrogen, chlorine, bromine, iodine, cyano, methyl ,ethyl,
Examples include propyl, butyl, pentyl, methoxy, ethoxy, phenyl, phenoxy, etc. Preferred phenols used in the present invention include phenol, unsubstituted phenol, 0-chlorophenol, 2,6-dichlorophenol, 0-cresol, tocresol, 2-tert-butylphenol, 2,6-dimethylphenol. ,2,3
-dimethylphenol, 2.6-ditert-butylphenol, 2.3.5-)dimethylphenol, 2,3゜6
-trimethylphenol, 0-phenylphenol, Q
- Benzylphenol, etc.

The concentration of phenols is about 0.5 to 70% by weight based on the reaction solution. If it is less than 0.5% by weight, the volumetric efficiency of the reactor will be poor, and if it exceeds 70% by weight, crystals of quinones will precipitate during the reaction, resulting in poor operability. As the oxygen source, in addition to pure oxygen, oxygen diluted with air or nitrogen can be used.

In the present invention, methyl alcohol is used as a solvent. Ethyl alcohol and propyl alcohol have lower selectivity towards quinones than when methyl alcohol is used as a solvent.

As the copper salt, cupric chloride is used in the present invention. The amount used is 1000 ml of methyl alcohol. 0.00 against
2 to 0.167 mol is used. If the concentration is less than 0.002 mol, the phenol oxidation rate is slow, while if the concentration exceeds 0.167 mol, side reactions will increase and the yield of the desired quinone will be low. Preferably o, oso ~ 0.140
Use moles. Within this range, the oxidation rate of phenols is high and the selectivity to quinones is also high.

The present invention is carried out in the presence of an alkali metal chloride together with cupric chloride. Alkali metal chlorides include lithium chloride, sodium chloride, potassium chloride, rubidium chloride, and cesium chloride, and when these are used in combination with cupric chloride, the oxidation rate of phenols increases, and the oxidation rate of the corresponding quinones increases. The yield is high.

The amount of the alkali metal chloride used is 0.5 to 10 moles per mole of cupric chloride. If it is less than 0.5 mol, the effect will be small, and if it exceeds 10 mol, the oxidation rate of phenols will be rather reduced, and the selectivity to the corresponding quinones will also be lowered. More preferably, 2.5 mol to 5 mol is used. In this range, the oxidation rate of phenols is high;
In addition, lithium chloride is preferable as the alkali metal chloride, which has a high selectivity to the corresponding quinones.Lithium chloride has a higher solubility in methyl alcohol than other alkali metal chlorides, so the concentration in the solution is low. High (good quality)

In the method of the present invention, the reaction pressure may be normal pressure, or if desired, either increased pressure or reduced pressure, provided that the oxygen pressure is 0.1
~500Kg/cd. Generally, the higher the oxygen pressure, the higher the oxidation rate of unsubstituted phenol and the higher the selectivity to the corresponding unsubstituted benzoquinone. Substituted phenols substituted with alkyl or alkoxy have a faster oxidation rate (and higher selectivity to the corresponding substituted benzoquinone) at the same oxygen pressure than unsubstituted phenols, i.e. lower oxygen pressures can be used.

In the case of unsubstituted phenol, the oxygen pressure is 30 K.
The oxygen pressure is preferably at least 200 Kg/-, and in consideration of equipment costs for producing unsubstituted benzoquinone, the oxygen pressure is preferably at most 200 Kg/-.

The reaction temperature varies depending on the phenol used, but is usually 0 to 120°C, preferably 20 to 100°C. Since the reaction rate of substituted phenol substituted with alkyl or alkoxy is higher than that of unsubstituted phenol, the reaction can be carried out at a lower temperature. Furthermore, a substituted phenol substituted with alkyl or alkoxy has a higher selectivity to the corresponding substituted benzoquinone than a non-purchased phenol.

The reaction time is usually about 0.5 to 10 hours. This method can be carried out in a batch or flow process.9 The product and catalyst can be separated, for example, by separating methyl alcohol from the reaction solution by distillation, followed by extraction with water and an organic solvent that is immiscible with water. This can be carried out by separating the aqueous layer containing the catalyst and the organic solvent layer containing the product, etc., and separating the benzoquinone from the organic solvent layer.

(Example) Example 1 Phenol 18.82 kg was placed in a 300 Ill stainless steel autoclave equipped with a stirrer filled with a glass beaker.
g (0,200 mol), cupric chloride 1.34 g (0,0
10 moles), 1.70 g (0,040 moles) of lithium chloride, and 90 g of methanol were charged, and then nitrogen was added to
Pressurize to Kg/-G, then apply oxygen gas to 100K.
g/c+JG (at room temperature, oxygen pressure at this point is 60 Kg/csiG), this autoclave was heated to 70°C, and from the time when the oxygen was consumed by the reaction and the total pressure became 100 Kg/csiG, Pure oxygen was constantly introduced into the reactor to maintain the total pressure at 100 Kg/c+jG, and the zero reaction time was 3 hours after the temperature was raised to 70°C. Thereafter, it was cooled to room temperature, the pressure was released, and the contents were taken out and analyzed by liquid chromatography.

The results are shown in Table 1.

Examples 2 to 6 and Comparative Example 1 Only the added amounts of cupric chloride and lithium chloride were changed, and the reactions were otherwise carried out under the same conditions as in Example 1. The results are shown in Table 1.

Table 1 Results of oxidation of phenol ■ Notebook Concentration CuClz mol/1000g CH3
0H Example 7 0.941 g of phenol (
0,01 mol), cupric chloride 0.134 g (0,001 mol), cupric chloride 0.134 g (0,001
mol), lithium chloride 0.170g (0,004 mol)
and 20 g of methyl alcohol were charged, then the pressure was increased to 50 Kg/aiG with nitrogen, and then oxygen gas was injected to 100 Kg/c*"G (oxygen pressure 4150
Kg/d), the autoclave was heated to 70°C and then held for 3 hours. Then cool to room temperature,
The pressure was released and the contents were taken out and analyzed by gas chromatography. The results are shown in Table 2.

Examples 8 to 15 Only the amount of lithium chloride added was changed, and the rest was the same as Example 7.
and total (reacted under the same conditions. The results are shown in Table 2.

Comparative Example 2 The reaction was carried out under the same conditions as in Example 7 except that lithium chloride was not added. The results are shown in Table 2.

Table 2 Effect of addition of lithium chloride Note ratio CuC 14 degrees; (: uC 11 mol/1000 g
CkOH brocade Benzoquinone selectivity: Total selectivity of hydroquinone including generated hydroquinone + benzoquinone Examples 16 to 19 0.001 mol of sodium chloride, potassium chloride, rubidium chloride or cesium chloride was added instead of lithium chloride, and the other The reaction was carried out under exactly the same conditions as in Example 7. The results are shown in Table 3.

Comparison fM3-5 O, oos moles of magnesium chloride, calcium chloride, or barium chloride were added instead of lithium chloride, and the reaction was otherwise carried out under exactly the same conditions as in Example 7. The results are shown in Table 3.

Table 3 Effect of proboscis 7 Specific injection rate CuC1z concentration---CuC11 mol/1
000g C! (sOH Nishiki Benzoquinone selectivity - 11 - Hydroquinone containing generated hydroquinone +
Benzoquinone base (10 i scale Example 20) 2.3.6-trimethylphenol was used instead of phenol, and the reaction was carried out under the same conditions as in Example 7 except for that.

2.3.6-) Conversion rate of trimethylphenol 100χ 2.3. Selectivity to 5-trimethylbenzoquinone 99.
5χ Comparative Example 6 Using sulfolane instead of methyl alcohol as a solvent
0 g was used, and the reaction was carried out under the same conditions as in Comparative Example 2. The results are shown in Table 4.

Comparative Example 7 The reaction was carried out under the same conditions as in Comparative Example 6 except that 0.003 mol of lithium chloride was added, and the results are shown in Table 4.

Table 4 Effect of solvent Note: CuClx concentration-----CuCl
x mol/1000g sulfolane benzoquinone selectivity --- Hydroquinone including hydroquinone produced ÷ total selectivity of benzoquinone Example 21 The initial pressure of nitrogen charged into the autoclave was 62 Kg/c
The reaction was carried out under the same conditions as in Example 1 except that dG was used (70°C, total pressure 100 kg/cdG, oxygen pressure 3.
0 Kg/d), the following results were obtained.

Phenol conversion rate 87.5χ Selectivity to benzoquinone 73.9χ Selectivity to hydroquinone 4.1χ [Effects of the invention] From the results in Table 1, it can be seen that cupric chloride was converted into methyl alcohol by 100%
0. In the reaction system in which 0.002 to 0.167 mol of copper chloride was added and lithium chloride was added, the selectivity to benzoquinone was high; on the other hand, the amount of cupric chloride added was 0.222 mol per 1000 g of methyl alcohol. In the case of moles, it is outside the scope of the present invention, and the selectivity to benzoquinone is low despite the addition of lithium chloride.

From the results in Table 2, when lithium chloride is not added, the conversion rate of phenol is low and the selectivity to benzoquinone is also low, but lithium chloride is added at 0.0% per mole of cupric chloride.
When 5 mol to 10 mol is added, the conversion rate of nihaphenol is high and the selectivity to benzoquinone is also high.

From the results in Table 3, it is observed that sodium chloride, potassium chloride, rubidium chloride, and cesium chloride have the same addition effect as lithium chloride, but magnesium chloride, calcium chloride, and barium chloride have no effect on improving the selectivity to benzoquinone.

As shown in Example 20, substituted phenols substituted with alkyl groups increase selectivity to the corresponding parabenzoquinone.

The results in Table 4 show that when sulfolane is used as a solvent, the addition of lithium chloride lowers the conversion rate of phenol and lowers the selectivity to benzoquinone. In this way, benzoquinone can be produced in high yield for the first time by combining a specific solvent and a specific catalyst.

Example 1 (Oxygen pressure at 70°C is 55Kg/aa
) and Example 21 (oxygen pressure at 70°C is 30 kg/
-), it is clear that lowering the oxygen pressure lowers the conversion rate of phenol and also lowers the selectivity to benzoquinone. In the present invention, the oxygen pressure is preferably 30, /- or higher.

Claims (1)

[Claims] 1) A method for producing quinones by reacting phenols with oxygen in the presence of a copper salt in a solvent, in which 1000 g of methyl alcohol is used as a solvent.
and in the presence of 0.5 to 10 mol of alkali metal chloride per mol of cupric chloride. Characteristic method for producing quinones. 2) Alkali metal chloride is 2 per mole of cupric chloride
．． The method according to claim 1, wherein the amount is 5 to 5 mol. 3) The method according to claim 1 or 2, wherein the phenol is an unsubstituted phenol. 4) The method according to claim 3, in which an oxygen pressure of 30 kg/cm^2 or more is used when producing quinones by reacting phenols with oxygen.