JPS61115066A - Production of indole - Google Patents

Abstract

PURPOSE:In reusing repeatedly a catalyst used in a reaction, to obtain the titled compound useful as a raw material for synthesizing perfume or amino acids industrially advantageously, by subjecting an aniline and an ethylene glycol to a gaseous-phase catalytic reaction. CONSTITUTION:In producing an indole by a short process by subjecting an aniline and an ethylene glycol of inexpensive raw materials to a gaseous-phase catalytic reaction, when a catalyst which was used in the reaction, deteriorated, brought into contact with an inert gas containing <=5vol.% oxygen in a 200-450 deg.C temperature range, recovered, and reused repeatedly, hydrogen, carbon monoxide, ammonia, etc. (preferably hydrogen) is used as a reducing agent, the catalyst is previously reduced and activated at about 200-450 deg.C, and used. Consequently, the activity of the catalyst is more improved, the activity is extremely stable, and the reaction can be continued for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a process for producing indoles from anilines and ethylene glycols.

(Prior art and their problems) Indoles are known as raw materials for the chemical industry, and indoles in particular have recently become important substances as raw materials for perfumes and amino acid synthesis.

There have been many attempts to synthesize indoles, but all of them produce many by-products and require expensive raw materials. It had problems such as a complicated manufacturing process.

Recently, a catalyst system has been discovered that is effective in the reaction of synthesizing indoles using inexpensive raw materials anilines and ethylene glycols and in a short process. For example, C
u-Cr, Cu-Co, Pd/Sho□, Pt/SjO
. The present inventors have conducted various studies while busy with this reaction, and have already clarified that the performance of the reaction can be improved by adding water to the reaction system, carrying out one reaction under pressure, etc. .

Furthermore, the present inventors have discovered that Cu, which is an element Ibi of the periodic table, and A1. We have found that a catalyst system containing one of Au and Au as an active ingredient is effective for the production of indoles, and the reaction was carried out over a long period of time.

The object of the present invention is to regenerate and activate the catalyst that has been used in the reaction in such a method for producing indoles, and to
An object of the present invention is to provide an industrial method for producing indoles that can be used repeatedly.

(Means for Solving the Problems) The present inventors have diligently studied methods for solving the above problems, and have regenerated the catalyst by bringing the deteriorated catalyst into contact with a gas containing oxygen at a temperature of 200 to 450°C. Furthermore, they discovered a method of reductively activating the regenerated catalyst and completed the present invention.

That is, 1. The method of the present invention uses anilines and ethylene glycols as raw materials and carries out a gas phase catalytic reaction in the presence of a catalyst containing a metal from Group Ib of the Periodic Table of Elements to produce indoles, which are used at least once in one reaction. This method for producing indoles is characterized in that the catalyst is regenerated and subjected to reduction activation treatment when used repeatedly in reactions.

The anilines used in the method of the present invention are generally
R is a compound represented by a hydrogen atom, ), a rogen atom, a hydroxyl group, an alkyl group, or an alkoxy group. For example, aniline, 0-·m- or p-toluidine, 0-·m- or p-haloaniline, 0-·m
-・MoL<J! p-hydroxyaniline, 0-・m-・
Alternatively, p-anisidine and the like can be mentioned.

Also, ethylene glycols are ethylene glycols.
These include dicol, propylene glycol, 1,2-7'tanediol, 1,2,4-butanetriol, glycerol, 2,3-butanediol, diethylene glycol and the like.

The catalyst used in the method of the present invention is a group Ib element C
It is a catalyst system containing one or more selected from u, AP, and Au as an active ingredient, and elements that can be combined with these include B, C1O, MP, and AI! .

Sl, P, S, Ca, Ti, Cr, Mn, Fe, Co.

NI, Zn, Ga, Ge, Se, Sr, Zr, Mo.

Ru, Rh, Pd, Cd, In, Sn, Sb, Te, B
a, La, Ce, W, Ir, Pt, T/, Pb, B8,
Th etc. can be mentioned. The above-mentioned catalysts may be used alone or supported on common carriers such as diatomaceous earth, activated clay, zeolite, silica, alumina, silica-alumina, titania, chromia, thoria, magnesia, calcia, and zinc oxide.

In the case of Cu and AP, raw materials for group Ib elements include nitrates, sulfates, phosphates, carbonates, norogenides, organic acid salts, etc. In the case of Au, chloroauric acid, alkali metal chloroaurates, etc. Can be used for gold cyanide and cyanide. For example, methods include mixing various raw materials, adding a small amount of water, and kneading with a kneader, etc., making various raw materials into an aqueous solution, adding a precipitant to this, and co-precipitating it as an insoluble precipitate; It can be prepared by impregnating various raw materials.

The obtained catalyst composition is usually dried at a temperature of 180° C. or lower, and suitable granulation additives, molding aids, etc. are added thereto and molded, or the catalyst composition is crushed and used as it is.

In the method of the present invention, such a catalyst is used in the production of indoles and is deteriorated. The catalyst is subjected to the regeneration treatment described below and then to the reduction activation treatment, and then used repeatedly.

In the method 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 any reaction mode such as fixed bed, fluidized bed or moving bed is possible.

The anilines and ethylene glycols introduced into the reactor are 0 ethylene glycols per mole of aniline.
．． 0.01 to 5 mol, preferably 0.05 to 1 mol.

The amount of introduced raw materials, anilines and ethylene glycols, is 0.01 to 10 hr-' at liquid hourly space velocity (LH8V).
After being vaporized in an evaporator, it is introduced into the reactor. Further, at that time, water vapor, hydrogen, carbon oxide, carbon dioxide, methane, nitrogen, neon, argon, etc. may be accompanied as a carrier gas. Among them, water vapor, hydrogen, and carbon oxide are preferable because they have the effect of increasing the service life of the catalyst.

The reaction temperature is in the range of 200 to 600°C, preferably 250°C.
~500°C.

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

Catalysts that have been used more than once for the production of indoles under the above conditions are subjected to regeneration treatment and then reduction activation treatment as follows.

That is, in the regeneration process, a deteriorated catalyst is regenerated by burning off carbonaceous matter deposited on the catalyst. As for the playback method.

For example, a method may be mentioned in which a deteriorated catalyst is brought into contact with an inert gas containing 5 vol% or less of oxygen at a temperature range of 200 to 450°C. In this regeneration method, the oxygen concentration is preferably 2% or less, and the inert gas is nitrogen,
Argon, helium, carbon oxide, water vapor, etc. are used. If necessary, heat treatment may be performed subsequently.

However, the regeneration method is not limited to the above regeneration method.

Then, when the regenerated catalyst is used repeatedly, it is subjected to the following 51C reduction activation treatment before starting one reaction.

In this reduction activation treatment, hydrogen, carbon oxide, methanol, ammonia, hydrazine, etc. are used as a reducing agent. Usually, when producing indoles, a hydrogen-containing gas is often used as a carrier, so it is convenient to use hydrogen as a reducing agent.

The reduction activation temperature is 100 to 500°C, preferably 200°C.
-450°C, more preferably 300-400°C. The processing pressure may be increased pressure, reduced pressure, or normal pressure.

The reduction treatment time may be as long as desired, but the catalyst performance becomes constant at 2 hours or more.

Usually, under pressurized to normal pressure, the time is at least 1 minute or more, preferably 30 minutes or more.

The above reducing agent may be used alone or after being diluted with an inert gas.

(Operation and Effects of the Invention) When a deteriorated catalyst is regenerated as in the present invention and the regenerated catalyst is repeatedly used, by performing a reduction activation treatment in advance, production K of indoles can be used more than once and deteriorated. The activity of the regenerated catalyst is further improved. The activity expressed by reductive activation is extremely stable, and the reaction can be continued for a long time.

In the method, an industrial method for producing indoles is provided, in which the catalyst used is regenerated, activated, and used repeatedly.

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Example 1 and Comparative Example 1 400 cc of a pellet-shaped catalyst carrying 13% silver was packed into a commercially available tablet-formed SiO□ having a diameter of 3 m and a height of 2.5 mm, having an inner diameter of 20 mI and a stainless steel reaction tube.

The reaction tube was kept at 350°C, and the molar ratio of pre-vaporized aniline, ethylene glycol, and water was 12:1.
The raw materials No. 10 were supplied to the reaction tube at a rate of 30,011/hr, and at the same time hydrogen gas was supplied at a rate of 60/STP/hr, and the indole synthesis reaction was carried out under normal pressure. After reacting for a certain period of time,
The catalyst regeneration conditions are: oxygen-containing gas inlet temperature of 300°C;
Oxygen concentration: 1.5vo1%, cylinder linear velocity: 15Ncx/s
Playback was performed using ec. After regeneration, the catalyst was further heat-treated at 500° C. in an air atmosphere for 15 hours. Thereafter, the temperature was raised to 320° C. in a N2 atmosphere, H2 was fed at a rate of 2/min for 1 hour, and the reaction was carried out again under the same conditions as before regeneration.

Table 1 shows the conversion rate of ethylene glycol in the reaction and the yield of indole produced. In addition.

The conversion rate of ethylene glycol and the yield of indole follow the definitions below.

Conversion rate of ethylene glycol=yield of indole; One reaction was carried out according to the method shown in Example IK, except that the high-temperature reduction activation treatment prior to one reaction was not performed.

Note) (2) indicates the conversion rate of ethylene glycol. (2) indicates the yield of indole. Example 2 and Comparative Example 2 The reaction was carried out according to the method shown in Example 1 and Comparative Example 1, except that the catalyst was changed.

The catalyst was the same as the catalyst carrier used in Example 1, with 2.5% copper supported thereon.

The conversion rate of ethylene glycol in the reaction and the yield of indole produced are shown in Table 2.

Note) ■ is the conversion rate of ethylene glycol ■ is the yield of indole

Claims (1)

[Claims] 1) In a method for producing indoles by subjecting anilines and ethylene glycols as raw materials to a gas phase catalytic reaction in the presence of a catalyst containing a Group Ib metal of the Periodic Table of the Elements, the catalyst used in the reaction is regenerated. , upon repeated use,
A method for producing indoles, which comprises performing a reduction activation treatment in advance.