JP2002155051A - Method for producing indole compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an indole compound from an aniline compound and an ethylene glycol compound, by which the improvement in the reaction activity of the catalyst system and the control in the deterioration of the reaction activity can be achieved. SOLUTION: This method for producing an indole compound, comprising subjecting the aniline compound and the ethylene glycol compound to a gas phase catalytic reaction in the presence of a group Ib metal-containing catalyst to produce the indole compound, characterized by bringing the aniline compound and/or the ethylene glycol compound into contact with the catalyst preliminarily subjected to a high temperature oxidative activation treatment to perform a reduction activation treatment before the reaction. Thereby, the reaction activity of the catalyst can be improved, and the deterioration of the catalyst with the passage of time can further be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing indole, and more particularly to a method for producing indole from aniline and ethylene glycol. Indole is known as a raw material for the chemical industry, and is particularly used as an important compound as a raw material for synthesizing fragrances and amino acids.

[0002]

2. Description of the Related Art Hitherto, studies on synthesizing indoles using anilines and ethylene glycols, which are inexpensive raw materials, have been actively conducted, and effective catalyst systems have been found. For example, Cu—Cr catalyst, Cu—Co catalyst, P
d / SiO ₂ catalyst, Pt / SiO ₂ catalyst (JP-A-56-3)
6451), CdS catalyst (JP-A-56-169668)
However, all of the catalyst systems have drawbacks such as low reaction activity and drastic decrease in reaction activity, and have not been usable as practical catalysts.

[0003] As a method of improving these disadvantages, Ag is used.
A method using a catalyst (JP-A-57-206656), a method in which the catalyst is oxidized at a high temperature before the reaction, and then a reduction treatment with hydrogen gas (JP-A-59-73567), and water is added to the reaction system A method (JP-A-58-46067) and a method in which the reaction is carried out under pressure (JP-A-58-225061) have been reported.

[0004] However, none of these methods can solve the problem sufficiently, and the disadvantages of low reaction activity and drastic decrease in reaction activity are hardly improved.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for improving the reaction activity of a catalyst system and a method for suppressing a decrease in the reaction activity when producing indoles from anilines and ethylene glycols.

[0006]

Means for Solving the Problems The present inventors have intensively studied a method for improving the reaction activity of a catalyst system and a method for suppressing a decrease in the reaction activity. It has been found that a method of contacting anilines and / or ethylene glycols for reduction activation is effective, and has reached the method of the present invention. That is, the present invention relates to (1) an oxidizing activation treatment at a high temperature prior to the reaction in the production of indoles by subjecting anilines and ethylene glycols as raw materials to a gas phase contact reaction in the presence of a Group Ib metal-containing catalyst. A method for producing indoles, comprising contacting an aniline and / or ethylene glycol with a catalyst which has been subjected to the above, and carrying out a reduction activation treatment, and (2) a temperature of the oxidation activation treatment of 350. The method for producing indoles according to (1), wherein the oxidation treatment is performed with a gas containing O ₂ , N ₂ O or air at a temperature in the range of 650 ° C. Or the method for producing indoles according to (1) or (2), wherein the temperature of the reduction activation by contacting with ethylene glycols is in the range of 200 to 500 ° C. A (4) among Group Ib metal is Cu, Ag and Au, selected indoles method according a catalyst containing (1) to (3) as an active ingredient one or more.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The anilines used in the method of the present invention are represented by the general formula (1)

[0008]

Embedded image (Wherein, R represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group, and n is an integer from 0 to 5). For example, aniline, o-toluidine, m-toluidine, p-toluidine, o-chloroaniline, m-chloroaniline, p-toluidine
Chloroaniline, o-hydroxyaniline, m-hydroxyaniline, p-hydroxyaniline, o-anisidine, m-anisidine, p-anisidine, 3,4-dimethylaniline, 3,5-dimethylaniline, 2,4-dimethylaniline Etc. are exemplified.

Examples of ethylene glycols include ethylene glycol, 1,2-propylene glycol, 1,2-butanediol, 1,2,4-butanetriol, glycerin, and 2,3-butanediol.

The catalyst used in the method of the present invention is a catalyst system containing, as an active ingredient, at least one selected from Cu, Ag and Au, which are Group Ib elements of the Periodic Table of the Elements. B, C, O, M
g, Al, Si, P, S, Ca, Ti, Cr, Mn, F
e, Co, Ni, Zn, Ga, Ge, Se, Sr, M
o, Ru, Rh, Pd, Cd, In, Sn, Sb, T
e, Ba, La, Ce, W, Ir, Pt, Tl, Pb,
Bi, Tb, and the like can be given. The above-mentioned catalyst is used alone or diatomaceous earth which is a usual carrier, activated clay,
It is used by being supported on zeolite, silica, alumina, silica-alumina, titania, chromia, thoria, magnesia, calcia, zinc oxide and the like.

The raw materials of the group Ib element include Cu and Ag.
In the case of sulphate, nitrate, phosphate, halide, organic acid salt, etc., in the case of Au, chloroauric acid, alkali metal chloroaurate, gold cyanide, alkali metal cyanide, etc. are generally used. Can be used for

As a method for preparing the catalyst, a usual kneading method, a coprecipitation method, an impregnation method, a method combining the above-mentioned methods, and the like can be applied. For example, a method of mixing various raw materials, adding a small amount of water and kneading with a kneader or the like, a method of forming various raw materials into an aqueous solution, adding a precipitant thereto, co-precipitating as an insoluble precipitate, various methods for various carriers, It can be prepared by a method of impregnating a raw material. The resulting catalyst composition is usually 1
It is dried at 80 ° C. or lower, and is then molded by adding an appropriate granulating additive, molding aid, or the like, or the catalyst composition is crushed and used as it is.

The catalyst containing the Group Ib element as an active ingredient thus prepared is activated before the reaction.

Next, a method for activating the catalyst used in the method of the present invention will be described. The catalyst activation treatment is performed by combining the following oxidation treatment and reduction treatment. 1. Oxidation activation treatment-350-65 for the above catalyst
Oxidation treatment with O ₂ , N ₂ O, air or the like is performed within the range of 0 ° C. 2. Reduction activation treatment-1. The catalyst which has been subjected to the oxidation treatment is subjected to a reduction activation treatment using an aniline and / or ethylene glycol at a temperature in the range of 200 to 500 ° C. and subjected to the reaction.

First, the oxidation treatment will be described in detail below. The oxidation treatment of the catalyst may be performed outside the reactor, or may be performed after the catalyst is filled in the reactor.

In this oxidation treatment, the oxidizing agent is O ₂ , N ₂
O, air and the like may be used alone or as a mixture thereof. Further, it may be used after being diluted with an inert gas such as nitrogen gas. Although the concentration of the oxidizing agent to be used is not particularly limited, it is preferable to use air or a mixed gas of air and nitrogen gas for economic reasons.

The supply flow rate of the gas is determined in consideration of the oxygen concentration, the pressure loss in the catalyst layer, etc., and is usually 5 m / sec.
The following may be sufficient.

The temperature of the oxidation activation treatment is from 350.degree.
The range of 00 ° C is preferred, and 450 ° C to 600 ° C is particularly preferred. The oxidation activation time varies depending on the type of catalyst, the treatment temperature, and the type, concentration, and supply amount of the oxidizing agent. However, since the catalyst performance becomes constant in a certain time, no further treatment is required. The processing pressure may be any of pressurization, decompression, and normal pressure. Usually, it is preferable to perform the oxidation activation treatment at least 5 hours or more under pressure or normal pressure. By performing this operation, the stability of the catalyst is improved, and a highly active reaction can be performed for a long time.

Next, the reduction activation process will be described in detail below. In carrying out the reduction activation treatment of the catalyst, it is convenient to carry out the treatment after charging the catalyst into the reactor, but it may be carried out outside the reactor.

In this reduction activation treatment, one component of aniline or ethylene glycol may be used alone or two components may be used as the reducing agent. Also, it may be used after being diluted with an inert compound,
An inert gas such as nitrogen gas may be supplied at the same time.

The amount of the aniline or ethylene glycol used as the reducing agent is not particularly limited, but the supply amount of the aniline is based on the liquid hourly space velocity (LHSV) with respect to the catalyst volume.
Is usually 0 to 100 hr ^-1 , preferably 0.05 to 10 hr ^-1 . The supply amount of ethylene glycol is usually 0 to 100 hr ^-1 , preferably 0.05 to 10 hr ^-1 in terms of liquid hourly space velocity (LHSV) with respect to the catalyst volume.

The reduction activation temperature is 200 to 500 ° C., preferably 200 to 450 ° C., and more preferably 250 to 4 ° C.
00 ° C. The reduction activation time varies depending on the type of catalyst, the processing temperature, and the type, concentration, and supply amount of the reducing agent. However, since the catalyst performance is constant over a certain period of time, no further processing is required. The processing pressure may be any of pressurization, decompression, and normal pressure. Usually, it is preferable to perform the activation treatment at least 1 minute, preferably 5 minutes or more under pressurized to normal pressure. By performing this operation, the activity of the catalyst is improved, and a highly active reaction can be performed for a long time.

The method of the present invention is characterized by a reduction activation treatment of a catalyst. By this reduction activation treatment before the reaction, the activation of the catalyst is improved, and a highly active reaction can be carried out for a long time.

In the method of the present invention, the reaction between the aniline and the ethylene glycol is carried out in the gas phase in the presence of the above-mentioned catalyst, but may be carried out in any of fixed bed, fluidized bed and moving bed reaction modes. is there.

The aniline and ethylene glycol introduced into the reactor are in the range of 0.01 to 5 mol, preferably 0.0 mol, of ethylene glycol per mol of aniline.
It is in the range of 5 to 1 mol.

The amounts of aniline and ethylene glycol as raw materials are 0.01 to 0.01 in terms of liquid hourly space velocity (LHSV).
It is in the range of 10 hr ^-1 , and is introduced into the reactor after vaporization in an evaporator in advance. At that time, steam, hydrogen, carbon monoxide, carbon dioxide, methane, nitrogen, neon,
Argon or the like may be accompanied as a carrier gas.
Among them, steam, hydrogen, and carbon monoxide are preferable because they have an effect of increasing the service life of the catalyst.

The reaction temperature ranges from 200 to 600 ° C., preferably from 250 to 500 ° C.

The reaction can be carried out under reduced pressure, normal pressure or increased pressure, but is preferably performed under normal pressure and increased pressure.

[0029]

EXAMPLES The present invention will be further described with reference to specific examples below, but the present invention is not limited to these examples. Example 1 32.0 g of Cu (NO ₃ ) ₂ .3H ₂ O was dissolved in 100 cc of water to prepare an impregnation liquid. Next, 50 cc of the above impregnating liquid was added to 35 g of a commercially available silica carrier (specific surface area: 270 m ² / g), and the mixture was allowed to stand for 1 hour. Then, filtration, 1
Dry at 20 ° C, then introduce air into the electric furnace,
For 5 hours (oxidation activation) to obtain a Cu / SiO ₂ catalyst. Each of the catalysts was filled into two 20 mm Pyrex (registered trademark) reaction tubes in an amount of 7 cc each, the temperature was raised to 280 ° C. in an N ₂ atmosphere, and a reducing solution of aniline and ethylene glycol having a molar ratio of 6: 1 was subjected to LHSV 0.1. 25hr ^-1
Nitrogen (8.6 Nl / hr) was sent to the container, and a reduction activation treatment was performed for 15 minutes. Thereafter, the temperature was raised to 360 ° C. under N ₂ flow, the reactor temperature was maintained at 360 ° C., and a raw material having a molar ratio of aniline and ethylene glycol of 8: 1 was LHSV 0.2
At 9 hr ^-1 , water (1.5 g / hr) and hydrogen (1.3 N
1 / hr) to carry out the reaction. The yield of indole in the reaction is shown in Table 1 [Table 1]. In addition, the yield of indole complies with the following definition. Indole yield = moles of indole formed / moles of ethylene glycol supplied × 100

Comparative Example 1 The reduction activation treatment (N_Two28 under the atmosphere
Heated to 0 ° C, molar ratio of aniline and ethylene glycol
LHSV 0.25 hr with 6: 1 reducing solution^-1And nitrogen
(8.6 Nl / hr) and activate for 15 minutes
Instead of N) _TwoHeated to 280 ° C under atmosphere, H_Two
Of Example 1 except that the substrate was activated for 15 minutes.
The reaction was performed as described above. Table 1 shows the yield of indole in the reaction.
The results are shown in [Table 1].

[0031]

[Table 1]

Example 2 Water Glass No. 3 (containing 29% of SiO _{2 and} 9% of Na ₂ O)
18 g of zinc nitrate and 20 ml of 69% nitric acid were added to an aqueous solution in which 153 g was dissolved in 2000 ml of H ₂ O to obtain a precipitate. After sufficiently washing the obtained precipitate with water, it is dried at 120 ° C., and calcined at 500 ° C., and is SiO ₂ —ZnO (weight ratio: 9:
The carrier of 1) was prepared. 100 cc of 17.0 g of silver nitrate
In water to obtain an impregnation liquid. Carrier (specific surface area 280m
² / g) To 35 g, 50 cc of the aforementioned impregnating liquid was added,
Left for 1 hour. After that, filtration, drying at 120 ° C., then introducing air into an electric furnace, and baking at 500 ° C. for 10 hours,
An Ag / SiO ₂ -ZnO catalyst was used. Hereinafter, Example 1
A reduction activation treatment was performed in the same manner as described above to carry out the reaction. The results are shown in Table 2 [Table 2].

Comparative Example 2 An Ag / SiO ₂ —ZnO catalyst was subjected to a reduction activation treatment in the same manner as in Comparative Example 1 to carry out a reaction. Table 2 [Table 2]
Shown in

[0034]

[Table 2]

[0035]

According to the present invention, not only the reaction activity of the catalyst can be improved, but also the decrease in the activity of the catalyst over time can be suppressed. That is, the conventional method can solve the conventional problem.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C07B 61/00 300 C07B 61/00 300 F term (Reference) 4C204 AB05 BB04 CB03 DB01 EB01 FB01 GB01 4G069 AA03 AA08 BA02B BC31A BC31B BC32A BC32B BC33A BC35B CB38 DA05 FA02 FB40 FB45 4H039 CA42 CH10

Claims (4)

[Claims] 1. A catalyst obtained by subjecting an aniline and an ethylene glycol as raw materials to a gas phase contact reaction in the presence of a group Ib metal-containing catalyst to produce indoles, wherein an oxidation activation treatment has been carried out at a high temperature in advance before the reaction. Aniline and / or ethylene glycol for reducing activation treatment. 2. The temperature of the oxidation activation treatment is from 350 to 650.
In the range of ℃, O _2, N ₂ O or process according to claim 1, wherein the indoles carrying out the oxidation treatment with a gas containing air. 3. The reduction activation temperature of contacting the catalyst with anilines and / or ethylene glycols is 200.
The method for producing an indole according to claim 1 or 2, wherein the temperature is in the range of -500 ° C. 4. The method according to claim 1, wherein the group Ib metal is Cu, Ag or Au.
4. The method for producing indoles according to claim 1, wherein the catalyst contains at least one selected from the group as an active ingredient.