JPH0314305B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing indoles from anilines and ethylene glycols. More specifically, when producing indoles by using anilines and ethylene glycols as raw materials and subjecting them to a gas phase catalytic reaction in the presence of a group B metal-containing catalyst, a catalyst that has been oxidized and activated at a high temperature before the reaction is used. This is a method for producing indoles, characterized by using the following methods. Indoles are known as raw materials for the chemical industry, and indoles in particular have become important substances in recent years as raw materials for fragrances and amino acid synthesis. There have been many attempts to synthesize indoles in the past, but all of them had problems such as a large number of by-products, expensive raw materials, and complicated manufacturing processes. 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, Cu-Cr, Cu-Co, Pd/
Examples include SiO ₂ , Pt/SiO ₂ , and CdS, but all of these catalyst systems have drawbacks such as severe reduction in reaction activity and low reaction activity, making them unsuitable for use as a practical tentacle. The present inventors have conducted various studies on this reaction and have already found that the performance of the reaction can be improved by adding water to the reaction system, carrying out the reaction under pressure, etc. Subsequently, as a result of further intensive studies, we found that by applying high-temperature oxidation activation treatment before the reaction to a catalyst system containing one of group B elements Cu, Ag, and Au as an active ingredient, The method of the present invention was achieved by discovering that the stability to the touch was increased and the reaction could be carried out over a long period of time without any change over time. That is, the method of the present invention uses anilines and ethylene glycols as raw materials, and when producing indoles by subjecting them to gas phase catalytic reaction in the presence of a group B metal-containing catalyst, an oxidative activation treatment is performed at high temperature in advance before the reaction. This is a method for producing indoles, characterized by using the catalyst according to the present invention. The anilines used in the method of the present invention have the general formula () (In the formula, R is a hydrogen atom, a halogen atom, a hydroxyl group,
This is a compound represented by an alkyl group or an alkoxy group. For example, aniline, 0-
m-・or p-toluidine, o-・m・or p-haloaniline, o-・m-・or p
-Hydroxyaniline, o-, m-, or p
- Examples include anisidine. Ethylene glycols include ethylene glycol, propylene glycol, 1,2-butanediol, 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 catalyst system containing one or more selected from group B elements Cu, Ag, and Au as an active ingredient, and elements that can be combined with these elements include B, Ag, and Au. C, O, Mg, Al,
Si, P, S, Ca, Ti, Cr, Mn, Fe, Co, Ni,
Zn, Ga, Ge, Se, Sr, Zr, Mo, Ru, Rh, Pb,
Cd, In, Sn, Sb, Te, Ba, La, Ce, W, Ir,
Examples include Pt, Tl, Pb, Bi, and Th. The aforementioned catalysts may be used alone or in the presence of common carriers such as diatomaceous earth, activated clay, zeolite, silica,
Alumina, silica alumina, titania, chromia, thoria, magnesia, calcia, zinc oxide,
It is used supported on activated carbon, etc. In the case of Cu and Ag as raw materials for group b elements,
Nitrate, sulfate, phosphate, carbonate, halide, organic acid salt, etc. In the case of Au, chloroauric acid, alkali metal chloroaurate, gold cyanide, alkali metal gold cyanide, etc. are common. Can be used for As a method for preparing the catalyst, the usual kneading method, coprecipitation method, impregnation method, and a combination of the above-mentioned methods can be applied. For example, a method of mixing various raw materials, adding a small amount of water, and kneading with a kneader, etc., a method of 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 raw materials. The obtained catalyst composition is usually dried at 180° C. or lower, and suitable granulation additives, molding aids, etc. are added and molded, or the catalyst composition is crushed and used as it is. The catalyst containing a group Ib element as an active ingredient prepared in this way is activated by the following method. Catalyst activation treatment 1. Reduction treatment: H ₂ , CO, CH ₃ OH, NH ₃ ,
In the case of dry reduction method using _{N2H4 etc.} , 50-450℃
Refunds will be made within the range of On the other hand, CH ₃ OH,
In the case of a wet reduction method using HCHO, _N2H4 , amines _, etc., the reduction is carried out at a temperature in the range of -10 to 100C. 2. Oxidation activation treatment: The catalyst subjected to the reduction treatment in Section 1 is subjected to oxidation treatment using O ₂ , N ₂ O, air, etc. at a temperature of 350 to 650°C. 3. Reduction treatment: The catalyst subjected to the oxidation treatment in Section 2 is reduced again using H ₂ , CO, CH ₃ OH, NH ₃ , N ₂ H ₄ , etc. at a temperature of 200 to 500°C. Provide for reaction. The method of the present invention is characterized by the oxidation activation treatment of the catalyst shown in the above 2 items. This high-temperature oxidative activation treatment before the reaction increases the stability of the catalyst and allows the reaction to be carried out over a long period of time without any change over time. 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 the 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 in the range of 0.01 to 5 moles of ethylene glycol per mole of aniline, preferably
It is in the range of 0.05 to 1 mole. The amount of introduced raw materials anilines and ethylene glycols is 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 being vaporized in an evaporator. Further, at this time, water vapor, hydrogen, carbon monoxide, carbon dioxide, methane, nitrogen, neon, argon, etc. may be entrained as a carrier gas. Among them, water vapor, hydrogen, and carbon monoxide are preferable because they have the effect of increasing the service life of the catalyst. The reaction temperature ranges from 200 to 600℃, preferably 250℃
~500℃ range. Reaction pressure is reduced pressure, normal pressure,
It can be carried out under any pressure, but normal pressure and pressurized conditions are preferable. The present invention will be explained below with reference to Examples. Example 1 and Comparative Example 1 35.0 g of Cu(NO ₃ ) ₂ ·3H ₂ O was dissolved in 100 c.c. of water to prepare an impregnation liquid. Next, 50 g of the above impregnating solution was added to 40 g of a commercially available silica carrier (specific surface area 290/g).
cc was added and left for 30 minutes. After that, 120
It was dried at ℃ and used as a Cu/SiO ₂ catalyst. Two Pyrex reaction tubes each having an inner diameter of 200 mm were filled with 8 c.c. of the same catalyst, and pretreatment was carried out using the following two different methods. After each pretreatment, the reactor internal temperature was maintained at 360℃, and the raw material with a molar ratio of aniline and ethylene glycol of 8:1 was heated at LHSV and 0.28hr ^-1 .
The reaction was carried out by feeding with water (1.6 g/hr) and hydrogen (1.5 Nl/hr). The results are shown in Table 1. Pretreatment of Example 1: The temperature was raised to 250° C. in an N ₂ atmosphere, and a reduction treatment was performed by sending H ₂ for 15 minutes.
Next, the temperature was raised to 500° C. in an N ₂ atmosphere, and then air was introduced to perform oxidation activation treatment for 5 hours.
After substitution with _N2 , the temperature was lowered to 360°C, and reduction treatment was performed with _H2 , followed by use in the reaction. Pretreatment of Comparative Example 1: The temperature was raised to 250° C. in an N ₂ atmosphere, and H ₂ was sent for 15 minutes to perform a reduction treatment.
Thereafter, the temperature was raised to 360°C under H ₂ flow and used for reaction.

[Table] Indole yield based on ole.
Example 2 and Comparative Example 2 29.5 g of AgNO ₃ and 0.85 g of PbCl ₂ were dissolved in 100 c.c. of water to prepare an impregnating liquid. Next, 50 c.c. of the above-mentioned impregnating solution was added to 40 g of a commercially available alumina carrier (basicity: specific surface area 220/g) and left for 30 minutes. Thereafter, it was dried at 120° C. to obtain an Ag-Pd/Al ₂ O ₃ catalyst.
Thereafter, the same pretreatment and reaction as in Example 1 and Comparative Example 1 were carried out. The results are shown in Table 2.

[Table] Example 3 and Comparative Example 3 44.3 g of AgNO ₃ and ₁ g of HAuCl 4.4H ₂ O4R were added to 100 c.c.
was dissolved in water to obtain an impregnating solution. Next, 50 c.c. of the impregnating solution described above was added to 40 g of a magnesia carrier (specific surface area: 85/g) prepared by firing commercially available basic magnesium oxide at 500° C., and left for 30 minutes.
Thereafter, it was dried at 120°C to obtain an Ag-Au/MgO catalyst. Thereafter, the same pretreatment and reaction as in Example 1 and Comparative Example 1 were carried out. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. When producing indoles by subjecting anilines and ethylene glycols to a gas phase catalytic reaction in the presence of a Group B metal-containing catalyst, use a catalyst that has been oxidized and activated at a high temperature before the reaction. A method for producing indoles characterized by: