JP2844760B2 - Method for producing phenol - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing phenol from benzene and hydrogen peroxide in a liquid phase.

[Prior Art] Phenol is an industrially important compound as a raw material of phenol resin or bisphenol A or a raw material of aniline. The main phenol production methods currently industrially implemented include a cumene method and a toluene oxidation method. In the cumen method, phenol is produced by alkyne, oxidation and decomposition with propylene using benzene as a raw material, and in the method of oxidizing toluene, phenol is produced by oxidation of toluene and oxidative decarboxylation. In these methods, many reaction steps are required, and a more rational method for producing phenol is desired because, for example, acetone is co-produced in the cumene method.

In contrast, many attempts have been made to synthesize phenol in one step from benzene. As an example of synthesizing phenol in one step from benzene using hydrogen peroxide as an oxidizing agent, a method using a Fenton reagent utilizing oxidation and reduction of various metal ions is known. For example, Brook,
A et al. (J. Chem. Soc. Perkin Trans. II. 687-92 (1982))
It is shown that phenol can be produced from benzene and hydrogen peroxide using trivalent iron as a catalyst. Also,
Karakhanov.EA et al. (Neftechimiya, 27 (6), 791-5)
(1987)) also reported that phenol is formed from benzene and hydrogen peroxide using divalent or trivalent iron ions as a catalyst.

[Problems to be Solved by the Invention] However, in these reaction methods, a metal ion which is a catalytically active component reacts with hydrogen peroxide to generate phenol and is inactivated, and the reaction is generally performed. Is known to proceed only stoichiometrically.

[Means for Solving the Problems] In view of such a current situation, the present inventors have conducted intensive studies. Unexpectedly, when producing phenol from benzene and hydrogen peroxide in the liquid phase, the group VIII of the periodic table By using a zero-valent noble metal as a catalyst and causing hydrogen to coexist in the system, except that the transition metal ion, the post-transition metal element ion and 1,10-phenanthroline do not substantially coexist, the reaction is continuously performed. It has been found that phenol can be produced, and the present invention has been completed.

 Hereinafter, the present invention will be described in detail.

In the method of the present invention, a zero-valent noble metal of Group VIII of the periodic table is used as a catalyst. These noble metals need only have a valency of zero during the production of phenol, and therefore may exist in the form of a salt or complex of the noble metal before the production of phenol starts. Specific examples include zero-valent palladium, rhodium, ruthenium, platinum, and iridium. And their hydrochlorides,
Inorganic salts such as nitrates and complexes such as carbonyl complexes and ammine complexes can be used. Specific examples include chlorides such as palladium chloride, rhodium chloride, ruthenium chloride, platinum chloride, chloroplatinic acid, nitrates such as palladium nitrate, palladium acetate, and rhodium acetate, acetates, and tetraammine palladium dichloride.
Examples thereof include carbonyl complexes such as rhodium dodecacarbonyl, ruthenium dodecacarbonyl and tetraammineplatinum dichloride and ammine complexes.

These zero-valent or noble metal compounds can be used in a suspended or dissolved state in the system before starting the production of phenol. However, it is better to use the compound supported on a carrier in consideration of the separation of the product. preferable. The method of loading on a carrier is not particularly limited as long as it is a method for preparing a normal noble metal-supported catalyst, such as an impregnation method, a coprecipitation method, a precipitation method, and a physical mixing method, but the impregnation method is simple and preferred. As a method of adjusting a noble metal-supported catalyst by an impregnation method, a method is employed in which a desired amount of a noble metal compound is dissolved in a solvent such as water, alcohol, or benzene to impregnate the carrier, and then the solvent is removed. The removal of the solvent may be performed at an elevated temperature or under reduced pressure. In this way, the noble metal compound is supported, and after drying, the noble metal compound can be reduced under a gas flow of a gas having a reducing ability such as hydrogen to be used as a zero-valent noble metal supported catalyst.

The carrier on which the noble metal catalyst is supported is not particularly limited, and any of a neutral carrier, an acidic carrier, and a basic carrier can be used. Specifically, silica and activated carbon may be used as the neutral carrier, alumina may be used as the acidic carrier, and zirconia, magnesia, and titania may be used as the basic carrier.

The loading of the noble metal catalyst component is preferably 0.1 to 10%. 1
If it exceeds 0%, the effect of increasing the carried amount may be reduced. The amount of catalyst in the reaction system was
0.1-30 g is good, and 0.1-15 g is preferable.

The method of the present invention can be carried out by any of continuous, semi-batch and batch reaction methods.

The reaction temperature may be from 0C to 200C. If the temperature is lower than 0 ° C., the reaction rate becomes slow, and if it exceeds 200 ° C., an economical problem may occur. The reaction pressure is not particularly limited as long as the reaction is carried out in a liquid phase, and can be carried out at normal pressure or under pressure. Particularly when the reaction temperature exceeds the boiling point of the reaction raw material, the reaction is carried out under pressure.

In the method of the present invention, the reaction is carried out in a liquid phase, but the reaction may be carried out using a suitable solvent other than the starting materials benzene and hydrogen peroxide. Examples of the solvent include water, organic acids such as acetic acid and propionic acid, nitriles such as acetonitrile and propionitrile, and ketones such as acetone and methyl ethyl ketone. Can also be used. The amount of solvent used can be 0.1-90% by volume based on the total reaction. If it is more than 90%, productivity becomes poor and uneconomical.

In the method of the present invention, the reaction is carried out in the presence of hydrogen, but the amount of hydrogen is not particularly limited as long as the Group VIII noble metal catalyst used is kept at zero valence. The amount of hydrogen can be conveniently defined as the molar ratio of hydrogen to hydrogen peroxide present, but the ratio can be from 0.01 to 50.
And more preferably 0.1 to 20. The amount of hydrogen is 0.0
If it is less than 1, the effect of coexisting hydrogen is small, and if it exceeds 50, the further effect is small and uneconomical. There is no particular limitation on the method of supplying hydrogen, and the hydrogen may be diluted with a gas inert to a reaction such as nitrogen. If diluted with an inert gas, the volume may be diluted to 90% by volume. Exceeding this may cause economic problems.

[Effect] According to the method of the present invention, industrially important phenols can be produced under mild conditions and without requiring complicated reaction steps.

[Examples] Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 Palladium chloride was dissolved in 40 ml of a 1N hydrochloric acid aqueous solution, and 10 g of crushed 100 to 200 mesh silica gel (Carrierct, manufactured by Fuji Devison) was added thereto, followed by drying using a 60 ° C warm bath. This was reduced under a stream of 10% hydrogen (remaining nitrogen) to prepare a 0.5% Pd / silica catalyst.

20 ml of benzene and 80 ml of acetic acid were placed in a 100 ml reactor, and 1 g of the catalyst prepared above was added thereto. A 2.1 M aqueous hydrogen peroxide solution was supplied at a rate of 1.5 g / h. At the same time as the supply of hydrogen peroxide, hydrogen was supplied at 14.9 ml / min (H ₂ / H ₂ O ₂ = 1
2). The product was analyzed by gas chromatography. As a result, phenol was produced at 240 μmol / h.

Comparative Example 1 A reaction was performed in exactly the same manner as in Example 1 except that hydrogen was not supplied. As a result, 35 μmol of phenol was generated at the beginning of the reaction, but was not generated at all thereafter.

Example 2 A reaction was carried out in exactly the same manner as in Example 1 except that the supply amount of hydrogen was changed to 1.2 ml / min (H ₂ / H ₂ O ₂ = 1). As a result, phenol was produced at 260 μmol / h.

Example 3 In the same manner as in Example 1, a 2.5% Pd / silica catalyst was prepared. The reaction was carried out in exactly the same manner as in Example 1 except that 1 g of this catalyst was used. As a result, phenol was 120 μmol / h
Was generated by

Example 4 A 5% Pt / silica catalyst was prepared in the same manner as in Example 1 except that platinum chloride was used instead of palladium chloride. The reaction was carried out in exactly the same manner as in Example 1 except that 1 g of this catalyst was used. As a result, phenol was 10 μmol / h
Was generated by

Examples 5 to 7 The same procedure as in Example 1 was repeated except that activated carbon, titania and zirconia were used instead of silica.
% Palladium supported catalyst was prepared. The reaction was carried out in exactly the same manner as in Example 1 except that 1 g of each of these catalysts was used. Table 1 shows the results.

Example 8 Tetraamine palladium dichloride was dissolved in 40 g of water, 10 g of γ-alumina was added thereto, and the mixture was dried at 60 ° C. 150 ° C in a stream of 10% hydrogen (remaining nitrogen)
Was reduced with hydrogen to prepare a 0.5% Pd / alumina catalyst. The reaction was carried out in exactly the same manner as in Example 1 except that 1 g of this catalyst was used. As a result, phenol was produced at 75 μmol / h.

Example 9 A reaction was carried out in exactly the same manner as in Example 1 except that the amount of acetic acid was changed to 1 ml and 6 ml. As a result, phenol was 65
μmol / h and 179 μmol / h.

Example 10 A reaction was carried out in exactly the same manner as in Example 1 except that acetonitrile was used instead of acetic acid. As a result, phenol was produced at 47 μmol / h.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-42445 (JP, A) JP-A-64-42446 (JP, A) JP-B-45-36495 (JP, B1) (58) Field (Int. Cl. ⁶ , DB name) C07C 39/04 C07C 37/60 CA (STN)

Claims (1)

(57) [Claims] In producing phenol from benzene and hydrogen peroxide in a liquid phase, hydrogen is allowed to coexist in a system using a zero-valent noble metal of Group VIII of the periodic table as a catalyst, provided that transition metal ions and post-transition A method for producing phenol, comprising reacting a metal element ion and 1,10-phenanthroline substantially without coexistence.