SK257591A3 - Preparation method of p-benzoquinone - Google Patents

Abstract

This patent describes the procedure closed to the preparation of p-bezoquinone with the use of a homogeneous catalyst, while the catalytic effect is reached, when using 2, 2'- bipyridine copper complex compounds and it is based on this principle, that the solution closed to £Cu(bpy)2|+ -phenol- -acetonitrile with Cu(I) concentration value of 2.10exp(-2) mol.dm-3, phenol concentration value of 1.10exp(-1) up to 1 mol.dm-3 and molar ratio £Cu(I)| : £phenol| = 1 : 40 up to 1 : 60 is bubbled with di-oxygen, at the atmospheric pressure and at the temperature of 30 up to 50 Celsius degrees in the glass reactor, in the dark or in the radiation environment closed to the wave length value of 320 mm, for 100 minutes.

Description

Technical field

The invention relates to a process for homogeneous p-benzoquinone under the catalytic action of copper in acetonitrile.

2,2´- bipyridine complexes

The state of the art

Most of the previously known processes for the preparation of p-benzoquinone are based on the oxidation of phenol by various oxidizing agents ClOg (Wajon (1982)), Fremy's salt (Zimrner (1971)), tallow nitrate (mcKillop (19? 6)).

These methods are energy intensive, the selectivity of p-benzoquinone formation and its yield are very low. The most commonly used oxidants include oxygen in the presence of catalysts such as manganese, cobalt and copper complexes. (US Patent 4,208,339, US Patent 3,796,732, US Patent 3,859,317, US Patent 4,360,469, US Patent 4,442,036). However, the use of one of the most effective copper halide catalysts requires high partial oxygen pressure (up to 100 atm), which is a prerequisite for the desired yields of p-benzoquinone (US Patent 4,257,968, US Patent 3,987,068). The most effective was of cuprous chloride and copper in acetonitrile medium, whereas Cu (N0 _{3) 2,} Cu3r, Cu (DH) Cl, NaCuClj CuOCl and showed a substantially lower efficiency. The formation of p-benzoquinone also occurs with the use of CuCl ₂ as a catalyst in dimethylformamide, dimethylsulfoxide, 1,4-dioxane and ethylene glycol at temperatures up to 100 ° C and oxygen oxygen pressure of 35 kg / cm (Seltrame (1979)). acetonitrile in the presence of phenol, nitrates, and oxygenate resulted in a 100 V increase in p-benzoquinone yield (Czech.Pat. 232 126) over non-irradiated systems (Czech.Pat.232 629) but p-benzoquinone yields were very low (about 6 H). One disadvantage of this phenol oxidation process is the formation of toxic chlorophenols as by-products of the reaction.

SUMMARY OF THE INVENTION

The principle of the homogeneously catalyzed preparation of p-benzoquinone by oxidation of phenol with oxygen in a homogeneous phase under the catalytic action of (2,2'-bipyridine) of the copper complexes in the acetonitrile medium according to the invention consists in the solution of [Cu (bpy) 2H] -phenol. acetonitrile of the concentration of Cu (I) 2.1O ^"5 to 2:10 ^ mol.dm, phenol 1.10 mol.dm ¹ to 1 · ⁵ (molar ratio of (Cu (I) J: [fenolj» to 1:40 - 1: 60) is bubbled through oxygen at atmospheric pressure in a glass reactor at 15 to 50 ° C in the dark or during irradiation with polychromatic light having a wavelength of more than 8ko 320nm for over 100 minutes.

The essence of this process for the preparation of p-benzoquinone is the (photo) oxidation of phenol with oxygen, which has the character of catalytic cycles, including phenoxide radicals, copper complexes and activation of oxygen.

The advantages of the above process for the preparation of p-benzoquinone in comparison with previously published processes consist mainly in higher benzoquinone yield, lower energy intensity, simplicity of reaction (simple glass reactor) and mild exponential conditions (atmospheric pressure and near room temperature range). The reaction takes place in the dark, or using any source of radiation (^ _O 2> 320nm) which allows you to use the sunlight makes the process more attractive and in terms of converting solar energy into chemical and energy consumption is reduced. Toxic chlorophenols are not produced, which is of particular importance from an ecological point of view.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

(C10 _A ) _o in acetonitrile with a copper concentration of 1.10 ⁵ mol.dm &^lt; ^{3 >} with the addition of an excess of metallic (powdered) copper, for 20 minutes, after filtering off the unreacted copper, solid was added phenol r

so that the molar ratio of cu (I) J with [phenol] is L with 40 to 1:60.

After dissolution of phenol, 25 cnP of the thus prepared reaction mixture was transferred to a glass reactor in which it was bubbled with oxygen in the dark at 30 to 50 ° C for over 100 minutes at atmospheric pressure 0- (0.1 MPa) and a constant oxygen flow e " FROM

1.6 cm .s * ¹ * The formation of p-benzoquinone in the reaction mixture was determined by spectral and high performance liquid chromatography (HPLC system from WATERSC 990, DAO detector, S.EPARON C-13 column, ACN-water mobile phase at 0). , 5 cm ^ .min “^ ·). The p-benzoquinone calibration standard (standard) made it possible to quantitate the formation of p-benzoquinone, which was produced in amounts up to 9 times higher per mole of the meonium catalyst used, indicating the catalytic nature of the proposed process for the preparation of p-benzoquinone.

Example 2

The preparation of the reaction mixture was the same as in Example 3, but the other procedure was different in that 25 cm of the reaction mixture was irradiated in a glass reactor under the same experimental conditions with light having a wavelength of more than 323 nm (TESLA RVK 125 W lamp). ) to achieve a 62% increase in p-banzoquinone yield compared to non-irradiated solutions and up to 15 times the yield of p-benzoquinone per mole of catalyst used.

In the photocatalytic nature of the proposed process for the preparation shows the observed value of the quantum yield to afford p-benzo ^methanone BBCH f '· ²⁵

Industrial usability

Banzoquinones are important industrial chemicals (oxidizing agents, intermediates of many organic syntheses) and, after reduction to hydroquinones, are used in the production process of polymers. They are used as antioxidants and reducing agents.

Claims (1)

PATENT TOOLS Process for the homogeneously catalyzed preparation of p-benzoquinone under the catalytic action of 2,2'-bipyridine copper complexes in acetonitrile medium, characterized in that a solution of the composition of tert-butyl-4-phenol-acetonitrile at a concentration of Cu (I) of 2.10? ¹ : ¹ to mol.dm @ ^-1 and a molar ratio of [CuCl3]: pheno] J of 1:40 to 1:60 are bubbled through oxygen at atmospheric pressure at 30 to 50 ° C in a glass reactor in a time exceeding 100 minutes in the dark or under irradiation with radiation at a wavelength exceeding 320 nm.