JP2002338543A - Method for producing indole compounds - 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 reaction activity deterioration and low reaction activity of a regenerated catalyst system can be solved. SOLUTION: This method for producing the indole compound from the aniline compound and the ethylene glycol compound is characterized by burning off carbonaceous substances deposited on a deteriorated catalyst used for the reaction, subjecting the treated catalyst to an oxidative activation treatment at a high temperature, and finally bringing the catalyst into contact with the aniline compound and the ethylene glycol compound to carry out a reductive activation treatment. Thereby, the reaction activity deterioration and low reaction activity of a regenerated catalyst system can be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing indoles from anilines and ethylene glycols. More specifically, the present invention relates to a method for producing an indole, which comprises recycling a catalyst used in a method for producing an indole from an aniline and an 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-
No. 36451), CdS catalyst (JP-A-56-169)
No. 668), however, all of these catalyst systems have drawbacks such as a drastic reduction in reaction activity and a low reaction activity, and cannot be used as a practical catalyst. As a method for improving these disadvantages, Japanese Patent Application Laid-Open No. 57-2066 is already known.
No. 56 (US Pat. No. 4,476,310) proposes a method for producing indole or indole by reacting aniline or aniline and ethylene glycol in the presence of a silver catalyst supported on a carrier having a specific surface area of 10 m ² / g or more. ing.

[0003] However, even if the reaction is carried out using these catalysts, Japanese Patent Application Laid-Open No. 61-115,065 (US-483) does not apply.
As described in 1158), the catalyst deteriorates with the elapse of the reaction time, the conversion of ethylene glycols and the selectivity to indoles decrease, and the yield of indoles deteriorates. The deteriorated catalyst is disclosed in JP-A-61-115.
065 and JP-A-61-115066. Regeneration of deteriorated catalyst is made of combustion removal and oxidation activation and reductive activation process deposits carbonaceous, e.g., burning and removing processes of deposition carbonaceous, the reaction system was replaced with N _2, the temperature of the reaction tube Is set to 250 to 300 ° C., and N ₂ gas 5-1 containing 1.3 to 1.8 vol% of oxygen is used.
At a flow rate of 5 Ncm / sec, carbonaceous matter deposited on the catalyst is burned and removed. Further, the temperature of the reaction tube is raised to 450 to 500 ° C., the air is switched to air, and the oxidation activation treatment is performed for 10 to 15 hours. Next, the reduction activation treatment is usually carried out under normal pressure at a reduction temperature of 300 to 350 ° C. using hydrogen as a reducing agent at 5 to 15 Ncm / sec for 1 to 3 hours to activate the catalyst.

[0004] The deteriorated catalyst can be regenerated by performing the carbonaceous combustion removal, oxidation activation and reduction activation treatments, and the reaction can be repeated. However, even with these methods, deactivation of the catalyst activity is inevitable, and the drawback that the reaction activity decreases is not improved.

[0005]

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

[0006]

In the production of indoles from anilines and ethylene glycols, carbonaceous substances deposited on the deteriorated catalyst used in the reaction are burned off and then subjected to oxidation activation treatment at a high temperature. It was found that the object of the present invention can be achieved by contacting anilines and / or ethylene glycols for reduction activation treatment, and finally completed the present invention. That is, the present invention provides (1) a method for producing 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;
The degraded catalyst used in the reaction is reduced by (1) burning off the deposited carbonaceous material, (2) oxidizing activation treatment at a high temperature, and finally (3) contacting with anilines and / or ethylene glycols. A method for producing an indole characterized by carrying out an activation treatment; (2) an inert gas in which the combustion removal treatment of the deposited carbonaceous material is in a temperature range of 200 to 450 ° C., and the oxidation activation treatment is an oxygen concentration of 2 vol% or less. (1) The method for producing indole according to the above (1), wherein the oxidation activation treatment is carried out by using gas, air, O ₂ or N ₂ O as an oxidizing agent.
(1) The method for producing an indole according to the above (1) or (2), which is carried out for 5 hours or more in a temperature range of 50 to 650 ° C .; (5) a method for producing indoles according to (1) to (3), wherein
The above-mentioned (1) to (1), wherein the Ib group metal is a catalyst containing at least one selected from Cu, Ag and Au as an active ingredient.
(4) a method for producing indoles of (4), a catalyst degraded by use in the reaction is subjected to a combustion removal treatment of deposited carbonaceous material, then an oxidation activation treatment at a high temperature, and finally a reduction activation treatment;
The above (1) to which the cycle of reacting anilines and ethylene glycols with the activating catalyst is repeated.
(5) A method for producing an indole.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The anilines used in the method of the present invention are represented by the general formula (I)

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 1 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 the 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 the group Ib elements of the periodic table, Cu, Ag and Au,
As elements which can be combined with these, B, C, O, Mg, Al,
Li, P, S, Ca, Ti, Cr, Mn, Fe, Co, Ni, Zn,
Ga, Ge, Se, Sr, Mo, Ru, Rh, Pd, Cd, In,
Sn, Sb, Te, Ba, La, Ce, W, Ir, Pt, Tl,
Pb, Bi, Tb and the like can be mentioned. The above-mentioned catalyst is used alone or supported on a usual carrier such as diatomaceous earth, activated clay, zeolite, silica, alumina, silica-alumina, titania, chromia, thoria, magnesia, calcia or zinc oxide. Examples of the raw material of the Ib group element include sulfate, nitrate, phosphate, halide, and organic acid salt in the case of Cu and Ag, and chloroauric acid, alkali metal chloroaurate, and gold cyanide in the case of Au. ,
Alkali metal cyanide and the like can be generally used.

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, b. A method of mixing various raw materials, adding a small amount of water, and kneading with a kneader or the like; A method in which various raw materials are converted into aqueous solutions, a precipitant is added thereto, and coprecipitation is performed as insoluble precipitates; c. It can be prepared by a method of impregnating various carriers with various raw materials. The obtained catalyst composition is usually dried at a temperature of 180 ° C. or lower, and then molded by adding an appropriate granulating additive and a molding aid, or the catalyst composition is used by crushing the catalyst composition as it is. In the method of the present invention, the catalyst which has been deteriorated by using such a catalyst for the production of indoles is repeatedly used by performing a combustion removal treatment of deposited carbonaceous material, an oxidation activation treatment, and a reduction activation treatment described later. I do.

In the process of the present invention, the reaction between anilines and ethylene glycols is carried out in the gas phase in the presence of a catalyst, but can 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 0.1 mol, of ethylene glycol per mol of aniline.
It is in the range of 0.5 to 1 mol. The introduction amounts of the raw materials aniline and ethylene glycol are determined by the liquid hourly space velocity (LHS).
V) is in the range of 0.01 to 10 hr ^-1 , and is introduced into the reactor after vaporization in an evaporator in advance. At that time, water vapor, hydrogen, carbon monoxide, carbon dioxide, methane,
Nitrogen, neon, argon, or the like may be included 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 is in the range from 200 to 600C, preferably in the range from 250 to 500C. The reaction can be carried out under reduced pressure, normal pressure or increased pressure, but preferably at normal pressure or increased pressure.

The catalyst used once or more for the production of indoles under the above-mentioned conditions is subjected to a combustion removal treatment of deposited carbonaceous material, an oxidation activation treatment and finally a reduction activation treatment as follows. In the combustion removal treatment of the deposited carbonaceous matter, the deteriorated catalyst burns off the carbonaceous matter deposited on the catalyst. In burning and removing carbonaceous matter deposited on the catalyst,
Although it is cost-effective to carry out the catalyst as it is without removing it from the reactor, the catalyst may be taken out. As a combustion removal treatment method, for example, a deteriorated catalyst
A method of contacting with an inert gas containing 5 vol% or less of oxygen in a temperature range of 0 ° C. In this regeneration method, the oxygen concentration is in the range of 5 vol% or less, preferably 2 vol% or less, and nitrogen, argon, helium, carbon monoxide, steam, or the like is used as the inert gas.
The processing pressure at the time of combustion removal may be any of pressurization, decompression, and normal pressure, but is generally performed at normal pressure. The combustion removal of the deposited carbonaceous material is performed until the carbonaceous matter deposited on the catalyst is no longer detected as carbon dioxide or carbon monoxide by gas chromatography.

[0012] Oxidation activation treatment is carried out subsequent to the operation for burning and removing the deposited carbonaceous material. When the catalyst is subjected to the oxidation activation treatment, it is advantageous in terms of cost to carry out the catalyst as it is without removing it from the reactor, but the catalyst may be taken out. In this oxidation activation treatment, the oxidizing agent is O ₂ , N ₂ O, air, or the like, and these may be used alone or in combination. Further, it may be used after being diluted with an inert gas such as nitrogen gas. The concentration of the oxidizing agent used is not particularly limited, but 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, and the like, but is usually 5 m / sec or less. The temperature of the oxidation activation treatment is preferably in the range of 350 ° C to 600 ° C,
0 ° C to 600 ° C is particularly preferred. The oxidation activation time is
Although it varies depending on the type of catalyst, the processing temperature, and the type, concentration, and supply amount of the oxidizing agent, the catalytic performance becomes constant over a certain period of time, so that no further processing is required. The processing pressure may be any of pressurization, decompression, and normal pressure. Usually, under pressurized to normal pressure, at least 5 hours or more, preferably 10 to 2 hours
The oxidation activation treatment is preferably performed in 0 hours. By performing this operation, the stability of the catalyst is improved, and a highly active reaction can be performed for a long time. The oxidation activation treatment is performed for 5 hours or more, preferably for 10 to 20 hours.

Finally, the catalyst which has undergone the combustion removal treatment of the deposited carbonaceous material and the oxidation activation treatment is subjected to a reduction activation treatment in the following manner. In carrying out the reduction activation treatment, it is advantageous in terms of cost to carry out the catalyst as it is without removing it from the reactor, but the catalyst may be taken out. In this reduction activation treatment, either aniline or ethylene glycol may be used alone, or a mixture thereof may be used as the reducing agent. Further, a single substance or a mixture may be used after being diluted with an inert compound, or an inert gas such as a nitrogen gas may be supplied at the same time. The amount of the aniline and / or ethylene glycol used as the reducing agent is not particularly limited, but the supply amount of the aniline is usually 0 to 10 in terms of liquid hourly space velocity (LHSV) with respect to the catalyst volume.
0 hr ⁻¹ , preferably 0.05 to 10 hr ⁻¹ . The supply amount of ethylene glycols is based on the catalyst volume.
The liquid hourly space velocity (LHSV) is usually 0 to 100 hr ⁻¹ ,
Preferably it is 0.05 to 10 hr ^-1 . The reduction activation temperature is 200 to 500 ° C, preferably 200 to 450 ° C.
° C, more preferably 250-400 ° 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 sequentially performing the above operations, the activity of the regenerated catalyst can be improved, a highly active reaction can be performed for a long time, and a highly active state can be maintained even in repeated use. The "reduction treatment with anilines and / or ethylene glycols" of the post-oxidation catalyst carried out as described above is a feature of the method of the present invention. In the production of indoles according to the present invention, a decrease in the activity of the catalyst is suppressed. In addition, the selectivity of indole can be maintained for a longer reaction time. In addition, in the method of the present invention, the catalyst activation treatment and the indole production reaction can be performed in the same reactor. Therefore, by repeating these treatment-reaction cycles, a method advantageous in terms of indole production cost can be obtained. It is.

[0014]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. Example 1 Using water glass and zinc nitrate as raw materials, SiO ₂ -Zn was formed by a coprecipitation method.
An O carrier was prepared. A silver-supported catalyst was prepared by supporting 10 wt% of silver on this carrier. 250 ml of this catalyst is
mm, the reaction tube was filled with 365 mm.
C., and a raw material having a molar ratio of 8: 1: 30 in aniline, ethylene glycol, and water previously vaporized in 1: 1.
80 g / hr and at the same time 40 Nl / h of hydrogen gas
r to the reaction tube, and the indole synthesis reaction is performed at 0.4 Mp.
a. After reacting for a certain period of time, the catalyst was regenerated by the following procedure. For burning and removing carbonaceous matter adhering to the catalyst, the inside of the reaction system is replaced with N ₂ , the temperature of the reaction tube is set to 300 ° C., and N ₂ gas containing 1.5 vol% of oxygen is about 150 N
L / hr was passed. Then, the temperature of the reaction tube was raised to 50.
The catalyst was subjected to an oxidation activation treatment at 0 ° C. in an air atmosphere for 15 hours. Thereafter, the temperature was lowered to 320 ° C. in a N ₂ atmosphere, and a reducing solution of aniline and ethylene glycol having a molar ratio of 8: 1 was added to LH.
At an SV of 0.30 hr ⁻¹ , the mixture was fed with nitrogen (52 Nl / hr), and a reduction activation treatment was performed for 30 minutes. Thereafter, the reaction was performed again under the same conditions as before the catalyst regeneration.

Table 1 shows the conversion of ethylene glycol and the selectivity of indole in the reaction. The conversion of ethylene glycol and the selectivity of indole are defined as follows. Ethylene glycol conversion (%) = [(moles of ethylene glycol consumed) / (moles of ethylene glycol supplied)] × 100 Selectivity of indole (%) = [(moles of indole produced) / (Number of moles of ethylene glycol reacted)] ×
100

Comparative Example 1 According to the method described in Example 1, the reaction was carried out without performing only the reduction activation treatment before the reaction. The results are also shown in Table 1.

[Table 1]

Example 2 and Comparative Example 2 In accordance with the method shown in Example 1 and Comparative Example 1, the reaction was carried out using only the catalyst. The catalyst was obtained by loading 3.4% of copper on a commercially available silica carrier (specific surface area: 280 m ² / g). Table 2 shows the conversion of ethylene glycol and the selectivity of indole in the reaction.

[Table 2]

[0018]

According to the present invention, the carbonaceous matter deposited on the deteriorated catalyst used in the reaction is burned off, and then an oxidation activation treatment is carried out at a high temperature. Finally, anilines and / or ethylene glycols are brought into contact with each other, By performing the reduction activation treatment, the conversion rate and the selectivity after the regeneration of the catalyst hardly decrease even after the reaction for a long time, the sustainability of the activity is largely improved, and a highly active reaction can be carried out. That is, the method of the present invention provides an industrial method for producing indoles in which a catalyst to be used is regenerated and used repeatedly in a method for producing indoles from anilines and ethylene glycols.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) B01J 38/50 B01J 38/50 // C07B 61/00 300 C07B 61/00 300 (72) Inventor Tetsu Inoki Sodegaura, Chiba Prefecture 580-32 Mayoragaura F-term within Mitsui Chemicals Co., Ltd. CH10

Claims (6)

[Claims] 1. A method for producing indoles by subjecting anilines and ethylene glycols to a gas phase contact reaction in the presence of a group Ib metal-containing catalyst, wherein the catalyst used in the reaction is degraded by (1) Indoles characterized by carrying out combustion removal treatment of deposited carbonaceous material, (2) oxidation activation treatment at high temperature, and finally (3) reduction activation treatment by contact with anilines and / or ethylene glycols. Manufacturing method. 2. A process for burning and removing deposited carbonaceous matter from 200 to 4 times.
The method for producing indole according to claim 1, wherein the process is carried out in a temperature range of 50 ° C, and the oxidation activation treatment is carried out using an inert gas having an oxygen concentration of 2 vol% or less. 3. The oxidation activation treatment is performed by using air, O ₂ or N _2.
3. The method for producing an indole according to claim 1, wherein the method is carried out for 5 hours or more in a temperature range of 350 to 650 [deg.] C. using O as an oxidizing agent. 4. The temperature at which anilines and / or ethylene glycols are brought into contact with each other to reduce and activate them is 200 to 50.
The method for producing indoles according to claim 1, wherein the temperature is in a range of 0 ° C. 5. 5. The method for producing indoles according to claim 1, wherein the group Ib metal is a catalyst containing at least one selected from Cu, Ag and Au as an active ingredient. 6. The catalyst degraded by use in the reaction is subjected to a combustion removal treatment of deposited carbonaceous material, an oxidation activation treatment at a high temperature, and finally a reduction activation treatment, and then the anilines and ethylene glycols are activated. The method for producing indoles according to any one of claims 1 to 5, wherein a cycle of reacting with a catalyst is repeated.