DE1695434B2 - PROCESS FOR THE CATALYTIC PRODUCTION OF ALPHA- AND GAMMA-PICOLIN - Google Patents

Description

it was activated for 3 hours in a muffle furnace at 500 "C. The catalyst produced in this way had a fluorine content of 4.7 percent by weight.

They took 300 cc of this catalyst in a steel reactor with an inner diameter of 30 mm and directed lane 6 hours at a temperature of 400 ⁰ C per hour 1.25 Mo, acetaldehyde, and 2.94 moles of ammonia over the catalyst

The accumulated condensate was treated with 50% sodium hydroxide solution and distilled with steam. After further treatment with 50% sodium hydroxide solution, the distillate was separated into an aqueous one an oily phase.

The aqueous phase was extracted repeatedly with methylene chloride, and the extracts were combined with the oily Phase, the solvent was evaporated therefrom and the residue was analyzed by gas chromatography.

The following yields were determined based on the acetaldehyde introduced:

Λ-picoline 31 mole percent, y-picoline 22.6 mole percent, Pyridine 4 mole percent, 2 - methyl - 5 - ethylpyridine 2.3 mole percent.

The total conversion of acetaldehyde was 98.6%.

Examples 2 and 3

In two separate experiments, 2.27 moles of acetaldehyde and 1.96 moles of ammonia per hour were used for 6 hours long over a nac! Example 1 produced Catalyst with a F.'uorgehak of 4.7 percent by weight directed.

Table I below shows the reaction conditions and the results of the two examples compiled.

Table I. Table II

Implementation conditions

Implementation conditions

Fluorine content of the catalyst in percent by weight

Temperature in ⁰ C

Acetaldehyde conversion

in %

Bulging in mole percent,
based on the imported acetaldehyde

Λ-picoline

y-picoline

Pyridine

2-methyl-5-ethylpyridine

Example 2

4.7
418

97.5

28.8

20.1

4.1

2.5

Example 3

4.7
450

98.7

29.2

20 ^ 3

5.7

2.3

Examples 4 and 5

Silica-alumina with an alumina content of 13 percent by weight was treated according to the procedure of Example 1 with an aqueous hydrofluoric acid solution. Two different catalysts were produced therefrom which, after three hours of activation in air at a temperature of 500 ^° C., had an analytically determined fluorine content of 2.6 and 7.6 percent by weight, respectively.

The results obtained with these two catalysts and the respective implementation conditions are shown in Table 11 below.

Fluorine content of the catalyst in percent by weight

Temperature in ^C C

Required trial time

in hours

Introduced acetaldehyde

in moles / hour

Introduced ammonia

in moles / hour

Acetaldehyde Conversion

in %

Yields in mole percent,
based on the imported acetaldehyde:

Λ-picoline

y-picoline

Pyridine

2-methyl-5-ethylpyridine

Example 4 Example 5

2.6 390

2.27 1.67 99.7

27.4

23.8

2.5

7.6 406

1.25 3.58 98.9

27.4

23.7

3.1

2.5

Example 6

Made from a 14.6 percent by weight cadmium nitrate

Hydrate-containing aqueous solution was precipitated with concentrated sodium hydroxide solution cadmium hydroxide.

The cadminm hydroxide was washed for so long

until no more initiations were wrong wash water, and then dissolved in ammonia.

Silica-alumina having an alumina content of 13 percent by weight and a fluorine content of 7.6 weight percent was repeated impregnated with ammoniacal cMeser Cadmiumhydroxidlösung, wherein after each impregnator, drying was carried out at ^a C 110th

After three hours of activation in a muffle furnace at 400 ° C., the finished catalyst contained 5 percent by weight Cadmium oxide. 1.25 moles of acetaldehyde per hour were passed over 268 g of this catalyst for 6 hours and 3.53 mol of ammonia at a temperature of 400 ° C.

Based on the acetaldehyde introduced, the following yields were obtained:

Λ-picoline 31.4 mole percent, y-picoline 27.8 mole percent, 2-methyl-5-ethylpyridine 2.6 mole percent. The total acetaldehyde conversion was 93.5%.

Example 7

A reactor was charged with 300 ecm of silica-alumina with an alumina content of 13 percent by weight, and 2.27 mol of acetaldehyde and 1.76 mol of ammonia were then passed in per hour. The implementation was carried out for 6 hours at 43o ⁰ C.

The accumulated condensate was treated according to the procedure of Example 1 and then gas chromatographed analyzed, the following yield values being obtained based on the acetaldehyde introduced:

Λ-picoline 22.8 mole percent, y-picoline 24.2 mole percent, Pyridine 3.9 mol percent, 2-methyl-5-ethylpyridine 2.6 mol percent.

The total acetaldehyde conversion was 97.5%.

Claims (2)

Thetic fibers, furthermore in the production of coccidiostats, bactericides, weedkillers Patent claims: and antidotes. Another advantage of the invention is that 1. Process for the catalytic production of 5 one in general apart from \ - and y-picoline also considerable- - »- and y-picoline, from a mixture of vapors borrowed amounts of pyridine and? .- methyl-5-ethylpyridine of acetaldehyde and / or paraldehyde and ammo, which beniak is of great economic importance in a molar ratio of aldehyde: ammo sit. niak between 1: 0.5 and 1: 3 is to be performed at temperatures as additional ADVANTAGES ¹ that the erzwischen 350 and 50O ⁰ C, characterized marked io invention to be used in the catalyst is distinguished from a that the catalyst of a fluorinated silica-alumina -Mixture besides a fluorinated silica-alumina mixture with a high catalytic effectiveness also a large alumina content of 10 to 15% and a fluorine heat resistance tesiut and easy rain content of 2 to 10%. lets go. 2. The method according to claim 1, characterized in that, surprisingly, it has been found that indicates that the catalyst is 5 percent by weight, the high activity of such a Ka'dyators simply cent contains CdO as a promoter. by completely restoring the carbonaceous products that are during the Implementation deposited on the catalyst surface 20 have burns with air without affecting the fluorine content of the catalyst is reduced. The silica-alumina mixtures used for the preparation of the catalyst can by common Precipitation as well as by mixing the The invention relates to a method for the catalytic production of both components. Your clay ash According to the invention, the production of λ- and γ-picoline from one content is 10 to 15 weight levels from vapors of acetaldehyde and / or part percent. aldehyde and ammonia in a molar ratio of For the fluorination of the silica-alumina-aldehyde: ammonia between 1: 0.5 and 1: 3. Ammonium fluoride or bifluoride or that the catalyst is made from a hydrogen fluoride or other compounds which, under a fluorinated silica-alumina mixture with suitable working conditions, are able to develop hydrogen fluoride to an alumina content of 10 to 15% and a fluorine content, are used,
from 2 to 10%. The fluorine content of the finished catalyst is available There have already been processes for the production of λ- 35, preferably between 2 and 10 percent by weight, since in and y-picoline in the gas phase from aldehydes and in this area the best yields with a higher Ammonia using catalysts from the value of the ratio of Λ-picoline to γ-picoline Silica - Alumina with or without promotions on how to be achieved. z. B. salts or oxides of certain metals, such as Th, To increase the activity of the catalyst and Zn, Cd, Sn, Pb, Fe, Ni, etc. are known. 40 as a result, the yields of λ- and y-picoline continue to increase If you work alone in the presence of silica - can increase the fluorinated silica-alumina-alumina, so the y-picoline is formed in higher or almost a mixture of promoters, ζ. B. cadmium oxide, in technically the same yield as Λ-picoline. Can be added in the usual way by adding,
some of the above-mentioned promoters for a preferred catalyst preparation takes place, for. B. Silica - alumina, on the other hand, it was possible to increase the total yield of picolines using either commercial silica or alumina with an alumina content of 13 weight or the amount of picolines. Picoline to be increased somewhat compared to the amount of percent and pre-aqueous solutions of the fluorous watery-picoline. In the latter, the concentration of which corresponded to the desired case, the yield of Λ-picoline almost gives the fluorine content in the catalyst,
those of y-picoline or was even slightly higher 50 The following examples are intended to bring the invention closer than this. explain. Here example 7, which without using The most effective promoters include the discovery of fluorinated silica-alumina. lich some metal halides, ζ. B. ZnF ₂ , ZnCl ₂ or leads to a comparative test again.
PvF ₂ , but under certain conditions a Partial iron decomposition with formation of halogen 55 B bis The 1 1
Hydrogen can be subject to, which in turn a Able to cause corrosion of the system. 50 cm of an aqueous, 50% hydrogen fluoride In the method according to the invention, the Λ-picic acid solution falls were diluted with distilled water, lin in higher yield than the y-picoline. Such up to the volume received is your total volume of the The process is of great interest because it has 60 pores of 300 g of commercially available silica-alumina Λ-Picoline is of greater technical importance with an alumina content of 13% in small cylinders than the y-picoline. the one with the dimensions 1.587 1.587 mm In fact, the y-picoline is spoken almost exclusively. for the manufacture of pharmaceutical products from iso- The silica-alumina was mixed with hydrofluoricotinic acid used. On the other hand, the Λ-picoline solution is impregnated for only 8 hours if it is used over a large area, and the intermediate product is left at temperature. The impregnated silica numerous technical applications such as B. with the clay was then placed on the water bath under the Synthesis of Λ-vinylpyridine for rubber and syn- evaporated to dryness. Subsequently was