DE1695982A1 - Process for the preparation of piperidine and its alkyl homologues by catalytic hydrogenation of pyridine and its alkyl homologues - Google Patents

Description

Process for the preparation of piperidine and its alkyl homologues by catalytic hydrogenation of pyridine and its alkyl homologues The invention relates to a process for the preparation of piperidine and its alkyl homologues by Hydrogenation of pyridine and its alkyl homologues in the presence of catalysts at temperatures from 100 to 2000 C and pressures up to 250 at.

According to the main patent .......... (................) it is known Piperidine and its alkyl homologues by catalytic hydrogenation of pyridine and produce its alkyl homologues in the presence of nickel catalysts. by the hydrogenation at temperatures from 100 to 2000 0 and pressures up to 250 at, preferably at 110 to 1700 C and 5 to 50 at, in the presence of catalysts carried out at least 30% by weight, preferably more than 50% by weight, of metallic nickel on active alumina or ohromoxide or mixtures of these carrier substances.

It has now been found that the catalytic hydrogenation of pyridine and its alkyl homologues to piperidine and its alkyl homologues at temperatures from 100 to 2000 0 and pressures up to 250 at with equal success if you the implementation instead of nickel catalysts in the presence of Carries out cobalt catalysts that are at least 30% by weight, preferably more than 50 Contain% by weight metallic cobalt on active alumina.

It is also possible to work in the same way in the presence of catalysts that contain both metallic nickel and metallic cobalt on active alumina contain.

It is advantageous to work at temperatures of 110 to 170 cc and pressures from 15 to 200 at.

Example 1: In an autoclave with a volume of 1.6 liters, 300 g of pyridine with a sulfur content of 0.03% by weight and 30 g of a catalyst A. and Catalyst B, respectively, prepared in the manner described below were filled. Wasserstpff was then injected up to an initial pressure of 100 atm. After the autoclave was heated to 150 ° G within 2.0 hours, it became 4 hours at this temperature under a reaction pressure between 150 and 220 at held.

Catalyst A: An aqueous solution of cobalt nitrate and aluminum nitrate soda solution was added. The resulting precipitate was filtered off with suction Water washed free of nitrates, dried, ground with graphite and shaped into pills. The pills were reduced with hydrogen at 350 ° C. The resulting catalyst the composition had 6 moles of cobalt and 1 mole of alumina.

Catalyst B: zinc aqueous solution of cobalt nitrate and aluminum nitrate soda solution was added. The resulting precipitate was filtered off with suction Washed water free of entrainment, dried, ground with Craphit and shaped into pills. The pills were reduced with hydrogen at 310 ° C. The catalyst possessed the Composition: 25 moles of cobalt and 1 mole of aluminum oxide.

The reaction products obtained on the catalysts of the invention showed the following compositions: reaction product piperidine pyridine by-products % By weight of catalyst A 99.0 0.6 0.4 of catalyst B 98.8 0.6 0.6 Example 2: 30 cm3 Pyridine with a sulfur content of 0.03 wt .-% were per hour together with 600 nermal liters of hydrogen at 125 ° C continuously in a vertical position Introduced pressure reactor made of steel, the 300 cm3 of the catalyst B according to example 1 contained. In the course of the reaction, the decrease in the hydrogenation activity of the Catalyst compensated by gradually increasing the reaction temperature to 170 ° C.

The reaction mixture leaving the reactor was at room temperature cooled and relaxed to normal pressure.

The reaction product had at pressures of 5, 15, 50 and 220 at the the following composition: asac. at 5 15 50 220 wt. h piperidine 97 99, 5 98, 9 98, 5% by weight pyridine 0.8-1.0 0.1 0.1 0.1 Duration of the test in days 7 31 29 28 Example 3: In an autoclave of 1.6 liter volume was 300 g of pyridine with a sulfur content of 0.03 wt .-% and 25 g of a catalyst used in the below Way had been made, filled. This was followed by hydrogen at an initial pressure from 110 at. After the autoclave has reached 160 ° C within 1.5 hours was heated, it was kept at that temperature for 4 hours under a reaction pressure held between 150 and 220 at. The reaction products showed following composition: 98.7 wt .-% piperidine, 0.3 wt .-% pyridine, 1.0 wt .-% Byproducts.

The catalyst used was prepared in the following way: Binding aqueous solution of cobalt nitrate, nickel nitrate and aluminum nitrate was made mixed with soda solution.

The resulting precipitate was filtered off with suction, nitrate-free with water washed, dried, ground with graphite and shaped into pills. The pills were reduced at 350 0 with hydrogen. The resulting catalyst possessed the Composition 3 moles of cobalt, 3 moles of nickel and 1 mole of aluminum oxide.

Claims (3)

Claims: 1. Process for the preparation of piperdine and its Alkyl homologues by catalytic hydrogenation of pyridine and its alkyl homologues at temperatures from 100 to 200 ° C and pressures up to 250 at according to patent ........... (....................), characterized in that the implementation instead of nickel catalysts in the presence of cobalt catalysts, which comprises at least 30% by weight, preferably more than 50% by weight, of metallic cobalt Active alumina included. 2. The method according to claim 1, characterized in that the implementation is carried out in the presence of a catalyst which contains both metallic nickel as well as metallic cobalt on active alumina. 3. The method according to claim 1 and 2, characterized in that the Implementation carried out at temperatures of 110 to 170 cc and pressures of 15 to 200 at will.