CS255399B1 - Method of monomeric benzoquinones preparation by means of mono- and dimethylsubstituted phenols oxidation - Google Patents

Abstract

solution the relates to said process of preparation mono- mer benzoquinones oxidation mono · and dimetylsubstituovaných phenols. nature solutions is in how that solution Cu (I) Cl " - substituted phenol - acetonitrile about a horse- centering Cu (I) 1 : 10 -2 until 1 . TO -1 M . . dm -3 . phenol 1 : 10 _1 until 2 . 10 ' 1 M . . dm ' 3 and molar ratio (Cu (l) j : (C - ] equal the 1 : 6 until 1 : 10 the oxidizes dykyslí- com for atmospheric pressure in glass reactor at at 15 until 40 ° C During oža- Rovan polychromatic light about waveguides vej assembly by more than 320 nm after time over 60 minutes.

Description

The present invention relates to a process for the preparation of monomeric benzoquinones by oxidation of mono- and dimethyl-substituted phenols under the catalytic action of medium complexes, allowing the quinone to be obtained in high yield and high selectivity under mild conditions.

Benzocbinones are used industrially as oxidizing agents, they are intermediates in the synthesis of many organic substances, after reduction to hydroquinones it is used in the production of polymeric substances, they are used in sa as reducing agents, antioxidants, etc.

The essence of most of the proposed processes for the preparation of benzoquinones is the oxidation of alkyl substituted phenols with a suitable oxidizing agent in the condensed phase with or without the presence of a catalyst. Peroxic acetic acid (Jap. Pat. 55-95231), manganese dioxide (DOS 502 332), oxygenation in the presence of cobalt-malic acid complex (Jap. Pat. 54-28895), respectively, have been used as oxidation systems. salcomine (DE 2,460,665 C2; Rec. Trav. Chim. Pays-Bas, 36 [1967] 520) and metal oxides, peroxides, peracids (AO CSSR 207 934). The disadvantages of these processes are mainly low quinone yields and the formation of by-products. Increased conversion and selectivity can be achieved e.g. by increasing the temperature; eg. whereas in the dimethylphenol-salcomine-Oz system 2,6-dimethyl, 1-β-benzoquinone was obtained in 4 hours at 20 ° C in 25.0% -noim yield (AO ČSSR 207 934), at 65 ° C 2 5-dimethyl-p-benzoquinoline with 87% conversion and 90% selectivity (DE 2,460,665 C2). The use of Cu (II) complexes with tertiary amines as catalysts resulted in a mixture of polyphenylene ethers and (or diphenoquinones) in the presence of O 2 (US Pat. 3,306,874; US Pat. 3,306,875; US Pat. 3 210 384); dimeric quinones are also formed in the alkyl-substituted phenol-Cu system - halide ions - 02 (Fr. pat. 1 325 480; DE-OS number

221824).

• Other systems based on media complexes require autoclaving at elevated temperature and pressure; e.g. in the case of oxidation of substituted phenols with O 2 in the presence of Cu (I), Cu (II) salts, carboxylates and phenoxides, the autoclave was carried out at 60 ° C (Eur. Pat. Appl. 15, 22103), respectively. at a temperature of up to 150 ° C and a pressure of up to 103 bar in the presence of Cu (I) or Cu (II) ions, CN -, SCN ^- , NCCT and metallic) medium (DE 2 444 234 C2). In an analogous Cu (I) - Cu (II) system (GB Pat. 1511813), oxygen was used at a pressure of 7 to 200 atmospheres at a temperature of up to 100 ° C (at least 14 atm for mono- and dialkylphenols). In the case of the Cu (I) - Cu (II) - Cu ° and Cl ", Br, I ', CN', SCN, NCO" ions, the process was performed at 30 to 150 ° C (US Patent

870,731); however, the phenol conversion is low even after a longer reaction time. Some mono- and dimethyl-substituted phenols have been oxidized with O2 in the presence of Cu (I) and / or Cu (II) ions [Cu (II) ions preferably], Cl ',

Br, I ^- ions in solution under a pressure of up to 100 bar and a temperature of 50-70 ° C (DE-OS 2 221 624). The yields of the respective monomeric quinones obtained in this way (for 3 hours) ranged from 40.8% (for o-cresol) to 85% (for 3,5-dimethylphenol).

The knowledge of the use of light radiation for the preparation of methyl-substituted quinones has not been published.

Said drawbacks are eliminated in the preparation of monomer sp3sobu benzoquinones by oxidation of mono- and dimetylsubstituovaných dikyslíkom phenols in the presence of a copper complex in the acetonitrile solution, which is characterized in that a solution of Cu (I) - C ^- - substituted phenol - acetonitrile koncentráciácli of Cu [I) first 10 ^a to the first 10 ^_1 mol. . dm ^-3 , phenol 1. 10 ' ¹ to 2. 10 ^_1 mol. . dm ^-3 and a molar ratio of [Cu (I) J: [Cl ^- ] equal to 1: 6 to 1: 10 is oxidized by oxygen at atmospheric pressure in a glass reactor at 15 to 40 ° C during irradiation with polychromatic light of wavelength more at 320 nm for over 60 minutes.

Advantages of said process for the preparation of monomeric substituted benzoquinones are the! Compared to published procedures, mainly in lower energy intensity, in mild reaction conditions (room temperature and atmospheric pressure), use of cheap and available chemicals, achieving high phenol conversions (up to 100%), high quinone yields (up to 98%) with high selectivity (up to 98%) and simple design in a glass reactor of simple construction. An arbitrary radiation source is used, emitting light with a wavelength of more than 320 nm, which makes it possible to utilize solar radiation, thus making the process even more energy efficient.

The subject matter of the invention is described in the examples without being limited thereto.

Example 1

0.3362 g CuCL · and 1.4837 g LiCl were dissolved in 100 cm ^{3 of} acetonitrile with stirring. The brown solution of the copper (II) complexes was reduced to a colorless solution of the copper (II) complexes by stirring with an excess of powder medium (~ 1 gram). Then, the solution was transferred through a filter (to remove residual powder medium) to an oxygen-filled reaction vessel (150 cm ³ thermostatic glass reactor with submersible lamp and magnetic stirring). After actuating the lamp (medium pressure mercury lamp, NARVA 125W), 0.5041 g of 1-hydroxy-2-methylbenzene (crystals) was added through the side dosing arm to initiate the reaction. Another side arm was connected to a source of oxygen. The reaction was carried out at a temperature of 293 ° C and an atmospheric pressure of O2 (0.1 MPa). Spectral changes in the absorption of the reaction solution over time were monitored spectrophotometrically (UV-vis). Based on the knowledge of molar absorption coefficients, it was possible to quantitatively determine the consumption of phenolic substrate and the resulting quinone. These results were confirmed by 1 H-NMR spectra of the reaction products. Quantitative data on the reaction balance (phenol conversion, yield and quinone selectivity) are given for all examples in a common table. First

Example 2

A Cu (I) solution was prepared as in Example 1. The reaction was started by adding 0.5041 g of 1-hydroxy-3-methylbenzene. Reaction progress and result data were obtained as in Example 1.

Example 3

The reaction of 1-hydroxy-4-methylbenzene (0.3041 grams is carried out and quantitative data is given in an analogous manner to the previous examples 1, 2).

Example 4

To the Cu (I) solution prepared as in Examples 1-3, 0.6122 g of 1-hydroxy-2,4-dimethylbenzene was added at the start of the reaction; the reaction was conducted as well as the progress of the reaction as described above.

Example 5

The substrate used was 1-hydroxy-2,5-dimethylbenzene (0.6122 g), which was added to the solution of the copper (I) complexes in the reactor under the conditions as in Example 1. The material balance data were reported as described above.

substrate

FROM.....'

T a, b u 1 'k a 1

Conversion ⁺ [% 1 Monomeric ^[ quinone [%] yield Selectivity ³ · ⁺ [%] 72 65 90 68 60 88 56 45 80 92 88 98 100 98 98

⁺ Quantity per weighed substrate = 100%;

^{+ +} Quantity per substrate consumed = 100%

SUBJECT

Claims (1)

SUBJECT A process for preparing benzoquinones by oxidation of the monomeric mono- and dimetylsubstituovaných the phenols condensed] phase copper-catalyzed komplexemi characterized in that the solution of Cu (I) - C ^- - Phenol-substituted acetonitrile of the concentration of Cu (I) 1. 10 “ ³ to 1. 10 ^_1 mol. dm ^-3 , phenol 1. vynalezu. 10 “ ¹ to 2. 10 “ ¹ mol. dm ^-3 and the molar ratio [Cu (I) j: [Cl ^- ] = 1: 6 to 1: 10 is oxidized by oxygen at atmospheric pressure in a glass reactor at 15 to 40 degrees Celsius while irradiating with polychromatic light of wavelength more at 320 nm for over 60 minutes.