DE2006347A1 - Catalyst for the synthesis of ammonia - Google Patents

Description

Catalyst for the synthesis of ammonia

BATH ORIGINAL

The invention relates to a catalyst for direct ammonia synthesis from gaseous hydrogen and nitrogen. ': ■

The industrial processes used to date for the synthesis of Aimnoniaks are the Haber-Bosch process, the Claude process and the Mont Cenis method. As the main catalyst an iron oxide catalyst is used in the first two processes and a cyanoferrate complex salt in the latter process used. What all these catalysts have in common is that they are essentially composed of iron compounds as a catalytically active component and optionally off Activators exist and that they only take effect after a reduction treatment should be used.

Traces of oxygen or carbon monoxide also act on these catalysts as catalyst poisons and lead to a decrease in the catalytic effectiveness,

■ Die-catalysts according to the invention, which in their kind are completely new and one of the previously used

009832/1735

Catalysts have completely different compositions, characterized in that they are complex compounds at least one of the alkali metals with at least one of the transition nietallphthalocy.anine, at least one contain the transition metal porphyrins or with graphite.

These complex compounds belong to. the group of electron donor acceptor complexes or charge transfer complexes, in which the tfbergajagsmetallplithalocyanine, the transition metal porphyrins and graphite are the electron acceptors and the alkali metals are the electron donors.

The term alkali metals includes the following rietalle a: lithium, sodium, potassium, rubidium and cesium.

The remaining metal phthalocyanines are, for example, the phthalocyanines of iron, nickel, cobalt, tungsten, platinum, titanium, manganese, chromium, zirconium, hafnium, vanadium, molybdenum, osmium, Palladium, ruthenium, rhodium and iridium.

These transition metal porphyrins are, for example, porphyrins of iron, nickel, cobalt, tungsten, platinum, iridium, osmium, titanium, manganese, chromium, zirconium, hafnium, vanadium, molybdenum, Wk palladium, ruthenium and rhodium.

The catalysts according to the invention absorb a considerable amount of gaseous hydrogen and nitrogen and put a mixture of gaseous hydrogen and nitrogen catalytically into ammonia. An animonial education does not take place, however, if the gas mixture only via alkali metals, only via transition metal phthalocyanines, is passed only over transition metal porphyrins or only over graphite. In addition, the catalysts according to of the invention as well as the process of ammonia decomposition in the previously known catalysts is reversed. the The highest ammonia yield is therefore achieved at low temperatures and high pressures, i.e. on the side with a high equilibrium concentration of ammonia,

009832/1735 bad original

The catalysts according to the invention can "for example by one de ?? the following procedures can be established:

An excess of at least one of the alkali metals is used at least one of the transition metal phthalocyanines, at least one of the transition metal porphyrins or with graphite "in one Mixed temperature that is above the melting point of the alkali metals ^ "or the alkali metals is ·

When using transition metal phthalocyanines or "transition dietal porphyrins, the alkali metal" or the i

Alkali metals and the transition metal phthalocyanines or Transition metal porphyrins deposited on a carrier with a large surface and the mass thus obtained is at a temperature above the melting point of the Alkali metal or the alkali metals heat-treated.

The mention of these procedures concludes the application other process for the preparation of catalysts according to the invention does not stop.

The catalysts according to the invention consist of complexes Compounds between the alkali metals and the transition metal allphthal ο cya Hin en, the transition metal porphyrins or graphite and are according to one of the aforementioned methods manufacturable.

To activate the catalysts according to the invention, neither the addition of activators nor a reducing treatment with hydrogen. Furthermore increases the efficiency of the catalytic converters according to of the invention in the presence of gaseous oxygen does not depend.

The exemplary embodiments reported below serve to illustrate the invention and should not be sifted in a limiting manner. 009832/1735

example 1

0.5 g of iyctallirch.es sodium was placed on the inner wall of a glass, the U-tubes serve as heating vessels; 0.1 g of ion phthalocyanine was then evaporated onto this layer. These precipitated substances were then ^{tempered in a vacuum at 20O 0} C, whereby a deeply colored complex of iron phthalocyanine sodium formed. A Ki ;; ·.: ■ lukewarm. g of gaseous fuel and nitrogen were introduced and circulated at a speed of 12.2 ml / min. Dac volume of the "ΰι,: -:. 'Ά1ζ- system was approximately 140 ml The nech the BET specific surface Ve ν fahreη the complex Katalysetoz-c ^ betixi about 1 m / g'der in a cold trap collected ammonia mirde Analyzed quantitatively with the aid of gas chromatography and infrared spectrometry, the results are summarized in Table I. If the catalyst obtained in this way was exposed to 10 to 20 cm / 1 g of oxygen or carbon monoxide, its catalytic activity was practically unchanged.

H ₂ (cmllg) Tabel 110 I. NII 3 ^{/ N} 2 30th 170 30th Reaction stem ? 40 Amm ο η i a ka u s— Partial pressure of 30th temperature 260 bump after initiated 30th ⁰ C 240 20 hours 0 , 02 Gas 10 (ml under Nor 0 , 07 N ₂ painting conditions) 0 , 27 0.26 0 , 36 10 0.92 0 , 05 10 3.64 10 4.60 10 1.80 30th

009.832 / 1735

BATH ORIGINAL

Example 2 . ". -

The catalysts were prepared in the same manner as in Example 1, 0.5 g of the various alkali metals being reacted with 0.2 g of the various transition metal phbhalocyanines in the compilation shown in Table II refer corresponding .Katalysatoren performed Ammoniaksyfchese, wherein the surface of the catalysts returned $ e about 1 m / g. fraud. .

Partial of G-asei (CmHg) 10 30th Oabelle II 3 240 Ammonia- N H / N pressure initiated Up 10 45 200 \ yield 3 2 catalyst killed 15th 45 Reaction 240 after 20 ^N 2 10 45 temperature 240 hours 10 45 ⁰ G 240. (ml under 10 45 - ■ 240 Normal O , 24 conditions) O , 36 3.2 O , 42 10 O , 19th K-FePc * 18th O , 07 Na-CoPc ** 5.8 O , 17th Na-GoPc ** 2.1 Na-WPc ** 5.2. Na-PtPc ** Na-ClTiPc **

Pc »phthalocyanine ·.

* ■ The volume of the heating system is approx. 100 ml ** »The volume of the reaction system is approx. 210 ml

009832/1735. * "° ^HIGINAL

Example 5

0.5 g metallic matrium and 0.2 g Eiseuphfclialocyaniri were deposited on 0.1 g activated charcoal with a surface of about 600 Hi ⁴ µg and converted to the catalyst. The results of the ammonia synthesis carried out with this catalyst are shown in Table IET. The volume of the reaction system was about 140 ml.

(cmllg) 10 of Table III 25th Ammon ialcau s— m / IT 2 15th 50 prey after Partial pressure Reaction tem- 20 hours initiated H ₂ temperature (ml under Kor- Gas O. malbeding-. 015 N ₂ C. gene) O, 06 45 0 * 3 O, 45 1 * 2

Example 4

The catalysts wux'den in the same way as in example 1, with 0.5 g of metallic sodium and 0.2 g of transition metal tetraphenylporphine in the from Table IV apparent composition were implemented. The results of the catalysts shown in this way ammonia synthesis carried out are shown in Table IV. The volume of the reaction system was approx. 140 ml.

BATH ORIGINAL

009832/1735

-

Table IV

Catalyst partial pressure des

' introduced gas

- (cmtQg)

Reaction temperature

Or

Ammonia yield after 20

hours

^: (mT under ITormal conditions)

Na-OlFe (Hl) -tetraphenyl- porphine

Na-Oirin (IIT) -tetraplienyl- porphine

10

JO

30th

110 240

240

0.2

8.2

0.8

0.01 0.41

0.04

example

A graphite alkali metal complex catalyst was made by tTir-retting of approx. 2 g of graphite powder with approx. 2 g of alkali metal

in a vacuum "

O/

a glass U-tube.

In the reaction vessel kept at a certain temperature a hydrogen-nitrogen mixture is circulated at a rate of Ί2 ml / min. The volume of the TJmwäl ζ systems "is approx. 114 ml. The surface of the complex, which is determined with the aid of the BET method using Nitrogen was determined, was approx. 500 m / g.

009832/17

BATH ORIGINAL

The reaction product, the ammonia, was converted into a.n al ;; K '*: lfalle serving and in the' Jmwälasystem built in glass! U-tube, which has been cooled with liquid nitrogen, is collected and then analyzed with the aid of infrared spectrometry and Garchromatographie. The results are given in Tobelle Y.

Due to the presence of oxygen and carbon monoxide the activity of the complex hardly changed at all.

Table V

Catalyst partial pressure des initiated

Gas

(cmllg)

Reaction temperature

ο,

Ammonia yield after 12 buns (ml unler Normal conditions)

K graphite 5, 8th 9, 2 3OC 1 , 9 O, PA Na graphite 5, 8th O
- ', ? 300 O,

Example 6

5 was described

In the same as in example
The catalyst is made from one gram of eim ^: π Alkalinictalles and two grams of graphite. The results of the Amineninksynth.esο carried out with these catalysts are summarized in Table VI. The surface of the catalyst was approx. 20 m / g and the volume. dos reaction sycteir.n was approx. 510 ml.

009832/1735

ORIGINAL

Table VI • Reaction .Ammonia- - NH / N
3 2 Partial temperature yield, catalyst "print of ⁰ C after 20 initiated hours killed . (ml under 0.002 Gas ! • Tonnal 0.004 ' IT ₂ H ₂ conditions) 0.008 (cmllg) 306 0.06 0.008 8th; 24 325 0.11 K graphite 8 24 350 0.23 8 24- 300 ' 0.39 12 38 Eb graphite

Pat en t an st> rüclie;

BAD ORIGJNÄL

00 9832/17 35

Claims (1)

: P ate η ba η ε χ> r ü ch > j 1. Catalyst for the Aiumoniaksynthese, characterized in that £ he complex compounds with at least one of the alkali metals at least one of the Über ^ angsmetallphthalocyanine, at least one of the ÜLez-gang metal contains porphyrine or graphite. 2. Catalyst according to claim 1, characterized in that the : '■ · the alkali metal is lithium, sodium, potassium, rubidium, or cesium. Λ . J. Catalyst according to claim Ί, characterized in that the L ^ ergangsmetallphthalocyariin a phthalocyanine of iron, .Nikkeis, cobalt, tungsten, platinum, titanium, kangan, chromium, zircon ε, hafnium, vanadium, ilolybdenum, osmium, palladium, ruthenium, 'Is Rhodiums or Iridiums. 4. Catalyst according to claim 1, characterized in that the transition metal porphyrin is a porphyrin of iron, nickel, cobalt, Tungsten, platinum, iridium, osmium, titanium, manganese, chromium, zirconium, hafnium, vanadium, molybdenum, palladium, Is ruthenium or rhodium. ^ 5 · Method for producing Katn "i ^ -r, n boren according to one of the claims 1 to 4, characterized in that the alkali metal is deposited on a support that the phthalocyanine or the porphyrin dos transition uietails deposited on this Layer is evaporated and that the reaction sum catalyst is carried out by subsequent heat treatment in vacuo at a suitable temperature. 6. A process for preparing catalysts according to any one of claims 1 to 4, characterized in that equal amounts of alkali metal and graphite powder were mixed and in a vacuum at temperatures above the melting temperature of the alkali metal to {- are brought reaction. Dr.Qjfefe / Ur - 22 239 _{D oB} tGWAU 009832 / 173S