JPS5844659B2 - Manufacturing method of pyrrole - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for synthesizing pyrrole by contacting furan and ammonia in the gas phase in the presence of a catalyst containing silica-alumina as a main component.

Pyrrole is contained in coal tar, and is also produced by dry distillation of bone oil or ammonium mucilage acid, or by reduction of succinimide with zinc and acetic acid, but even with these methods, there are many by-products and raw material issues. Considering this, it cannot be said that pyrrole is suitable for industrial production.

On the other hand, as a method for producing pyrrole from furan, Yu
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1142153-9 (1956) or U.S. Patent No. 2
, 600, 289, etc.

According to these reports, pyrrole is produced by contacting furan and ammonia with a γ-alumina catalyst or a silica-alumina catalyst at 450 to 500°C, but the yield is only 50% at most.

Therefore, the present inventors conducted intensive research with the aim of improving the yield of pyrrole synthesis through the gas-phase contact reaction of furan and ammonia, and as a result, they developed a catalyst composition that produces pyrrole with higher yield and higher selectivity than conventional methods. This discovery led to the completion of the present invention.

In the present invention, when furan and ammonia are catalytically reacted in the gas phase, silica alumina with an alumina content of 10 to 27% is supported with an oxide of an alkaline earth metal, cadmium, tin, or boron. This is a method for producing pyrrole, which is characterized by using a catalyst prepared by

The silica alumina used in the present invention is manufactured from sodium silicate and aluminum sulfate or aluminum alkoxide, and the alumina content in the silica alumina is 10 to 10.
If 27% is used, pyrrole can be produced well.

In order to support the metal oxide on silica alumina, it may be supported by a commonly used impregnation method on molded silica alumina, or it may be mixed and supported during the preparation of silica alumina.

A preferred method for supporting metal oxides is as follows.

As an oxide, a water-soluble metal salt (for example, nitrate or acetate) is dissolved in a predetermined amount of water at a concentration of 0.1 to 5% based on silica alumina (silica alumina).
After this impregnation, the catalyst is formed in air at 400 to 600°C for 3 to 5 hours.

The reaction temperature for carrying out the present invention is 400 to 500°C, and the ratio is 1 mole of raw material furan (2 to 15 moles of ammonia, preferably 5 to 10 moles), and 0 to 20 moles of water vapor, preferably 5 to 15 moles. A mixed gas is supplied onto the catalyst and reacted.

The contact time between the catalyst and the mixed gas may vary depending on the reaction temperature, catalyst, and other conditions, but is preferably in the range of 1 to 15 seconds.

The present invention will be further explained in detail with reference to Examples below.

Example 1 630 parts of sodium silicate (10% aqueous solution) and sulfuric acid aqueous solution (]
:1) Add 142 parts, react at pH 3.0 for 3 hours, and add 14% aqueous ammonia to the reaction solution p)! 7.
After adjusting the temperature to 0 to 7.2, it was aged for about 1 hour.

914 parts of aluminum sulfate (20% aqueous solution) was added to this solution and stirred well.

Add 14% ammonia water again to adjust the pH to 7.0-7.
．． 2, filtered, washed with water, and dried at 130-120°C to obtain a cake-like product.

This cake-like material was crushed and collected.

This was fired at 600'C for 3 hours. The alumina content of the silica alumina thus obtained was 15%.

0.21 parts of calcium nitrate was dissolved in about 50 parts of deionized water and impregnated with 50 parts of the silica-alumina prepared above, and after evaporating excess water at 150-170°C, it was dissolved in a stream of air for 500 parts. It was baked at ℃ for 3 hours.

70 ml of the obtained catalyst was packed into a stainless steel reaction tube with an inner diameter of 27 m/m, and a mixed gas of 8 mol of ammonia and 10 mol of steam was added to 4000 G and 45 mol of ammonia to 1 mol of furan.
The feed was carried out at two reaction temperatures of 0°C and a contact time of 8 to 10 seconds.

Table 1 shows the results of collecting and analyzing the obtained product.

Examples 2 to 6 Experiments were conducted under the same conditions as in Example 1 using catalysts containing various metal oxides.

The results are shown in Table 2.

Claims (1)

[Claims] When catalytically reacting 17 oran with ammonia in the gas phase, silica-alumina (alkaline earth metal, cadmium, tin or boron oxide) with an alumina content of 10% to 27% was used. A method for producing pyrrole, characterized by using a supported catalyst.