DE1544007C3 - Process for reducing the paramagnetic gas content of a gas mixture - Google Patents

Description

30th

The invention relates to a method for reducing the paramagnetic gas content of a gas mixture by passing the gas mixture over a particulate reagent which is kept in a closed zone and consists of finely divided, in situ reduced copper on an aluminum oxide carrier containing _{Na 2 O.}

The methods used to date for reducing the content of a gas mixture of paramagnetic gas are based (1) on the use of an aqueous absorbent or reactive solution, (2) on the use of dry materials which are suitable for elevated temperatures, e.g. B. to 400 to 700 ⁰ C, are heated, (3) on the use of a dry reactive material that must be heated together with an added reagent, such as hydrogen, or (4) on the use of a copper reagent, which in a Magnesium silicate carrier is dispersed. The first of the mentioned methods has the disadvantage that undesired water vapor must be added to the gas stream, while the second and third methods have the disadvantage that in both cases the reagent has to be heated with the formation of a volatile product, such as water, which in turn comes from the Gas flow must be removed. The fourth method has the disadvantage that paramagnetic gases can only be removed from the gas mixture with high efficiency as long as the total loading of the reagent is low, and when the reagent is heavily loaded, the efficiency of removing the paramagnetic gas decreases very quickly.

From British Patent 8 35 751 a method for reducing the content of a gas mixture of paramagnetic gas is known, in which the gas stream is brought into contact with a particulate selective adsorbent which consists of a copper compound which, together with one or more compounds from the Group magnesium and / or iron and, if desired, cobalt and / or nickel on a carrier of 50% Fe ₂ O3, 24% Al ₂ Oj, 3% SiO ₂ , 8% TiO ₃ , 3% CaO and 4% Na ₂ O ( Page 2, line 9/11). According to the information in the examples, a magnesium silicate carrier is preferably used. The cleaning power and the capacity for absorbing the undesired impurities per unit volume is still insufficient in this known adsorbent, since the content of a gas mixture of paramagnetic gas, eg. B. oxygen, can be reduced to a maximum of 0.001% or 10 ppm (page 2, line 51/52). Most of the values that can be achieved by these known processes are 0.002% or 20 ppm (Examples 1, 4 and 5). However, these values are insufficient for many purposes.

The object of the invention is therefore to develop a method with the help of which it is possible to a more effective way of reducing the paramagnetic gas content of a gas mixture without doing so goes at the expense of economy and simplicity of the process.

It has now been found that this object can be achieved by passing a gas stream containing a paramagnetic gas in a closed zone over a reagent which consists of extremely finely divided copper, which is based on a certain amount of Na ₂ O. y-aluminum oxide support with a certain surface area has been deposited.

The invention relates to a process for reducing the paramagnetic gas content of a gas mixture by passing the gas mixture over a particulate reagent kept in a closed zone, which consists of finely divided, in situ reduced copper on an _{aluminum oxide carrier containing Na 2} O, which is characterized by this that a reagent is used which consists of 3 to 13% by weight of copper on a γ- aluminum oxide support with 0.1 to 1.5% by weight of Na ₂ O, based on the aluminum oxide support, and a surface area of at least 10 m ² / g and its particles have an average diameter of 1.0 to 2.38 mm.

With the method according to the invention it is possible, the paramagnetic gas from a one to remove a gas mixture containing paramagnetic gas in a more efficient manner than before, d. H. with the The method according to the invention can, for example, the oxygen content of a gas mixture down to less than 10 ppm, in particularly favorable cases even down to less than 1 ppm (cf. Comparative experiments described below and the information in Table I) below.

According to a preferred embodiment of the invention, a reagent is used which, in addition to the reduced copper an activator metal from the group silver, platinum, palladium, manganese, nickel, Contains cobalt, chromium and / or molybdenum in an amount that is up to 45% by weight of the total weight of Can be copper and activator metal.

The paramagnetic gas to be reduced is preferably oxygen.

The reagent used in the present invention consists essentially of two components, viz

finely dispersed copper as a reagent and a carrier material made of γ-aluminum oxide containing _{Na 2 O.} The copper is preferably mixed with one or more finely divided activator metals in the group specified above, the total amount of activator metal mixed with the copper not exceeding 45%, preferably 20% of the weight of copper + activator metal. Suitable activator metals are, for. B. silver, platinum, palladium, manganese, nickel, cobalt, chromium and molybdenum.

A ^ -aluminium oxide with a large surface area (BET surface area) of at least 10m ² / g and a particle size such that the particles pass through a sieve with a mesh size of 2.38 mm to 1.0 mm is used as the reagent carrier However, a sieve with a mesh size of 0.55 mm can be retained. It is also essential that the γ-alumina contain from about 0.1 to about 1.5% by weight of Na2O, which is bound with the alumina.

To prepare the reagent used according to the invention, a relatively concentrated aqueous solution of a copper salt is added by dissolving about 2.5 to about 3 parts by weight of a copper salt readily soluble in water, such as. B. CuSO ₄ · 5 H ₂ O, Cu (NO ₃ ) ₂ · 3H ₂ O or CuCl ₂ · 2 H ₂ O, in 1 part by weight of water. The water is preferably acidified with 5 to 10% by weight of a mineral _{acid such as HNO 3} or H ₂ SO _4. The water-soluble salts of the optionally used activator metals are dissolved in the copper salt solution in an amount which is necessary to provide up to 45% by weight of activator metal, based on the total weight of copper and activator metal. This concentrated aqueous solution is poured onto such an amount of γ-alumina that is necessary to give 3 to 13% by weight of reduced copper, based on the total weight of the reagent. The mixture is stirred briefly and then dried in an oven, for example at 110 to 160.degree. C., and then roasted at a temperature of 250 to 400.degree. C., preferably from 290 to 400.degree. During roasting, the copper salts and the activator metal salts are converted into the oxides or anhydrous metal salts so that they form a single phase with the aluminum oxide, which can be determined by examining the X-ray diagram. The mechanisms that take place in this stage of production have not yet been fully clarified in detail, but this stage is considered to be essential for the correct production of the highly effective reagent with high capacity used according to the invention.

The preparation of the reagent used according to the invention in the form of reduced copper is still underway completed by a hydrogen stream, preferably a hydrogen / nitrogen mixture, The roasted material is allowed to flow over a bed for about 30 minutes or more while the maintains the bed at a temperature of about 100 to about 400 ° C, thereby adding the roasted metal salt to the elemental metal is reduced. To achieve a complete reduction, double the stoichiometric is sufficient Amount of hydrogen. The reagent obtained consists of extremely finely divided copper, the optionally finely divided activator metal is mixed in, which is in a γ-aluminum oxide carrier with large Surface is dispersed.

While the previously known reagents for removing a paramagnetic gas from a Gas mixture in the freshly prepared state and in the regenerated state have a higher effectiveness, which decreases rapidly with increasing duration of its use, is in the case of the invention Reagent does not require such activation, but it is also not disadvantageous.

The dynamic effectiveness of the invention

The reagent used, on the other hand, is influenced by the reduction or regeneration temperature used. The higher the temperature during regeneration, the higher the effectiveness during the later use over a long period of time.

It also increases the bed capacity. However, if the regeneration temperature is too high the carrier is liable to be degraded, resulting in a decrease in the effectiveness and capacity of the reagent leads. In general, a regeneration temperature of from about 250 to about 300 ° C., preferably from about 270 ° C.

The reagent prepared and reduced as described above is used according to the invention in such a way that it is introduced into a closed zone or into a closed tube, wherein there is intimate contact between the. Reagent and the gas mixture flowing through the closed zone or tube takes place. The reagent does not need to be heated, as it is effective even at the temperature of dry ice (-78 ° C) and liquid nitrogen (-196 ° C) However, it is also effective at the temperature of the surrounding space, and this temperature is generally preferred, although higher temperatures can also be used, since one of the advantages of the reagent used in the invention is its great effectiveness and capacity, even at room temperature is achieved, temperatures above 100 ° C. are generally not preferred, unless they are absolutely necessary, for example to keep a high-boiling liquid in the vapor state. It is assumed that the pressure of the invention has little or no influence. All paramagnetic Gases readily react selectively with the reagent used in the present invention; B O ₂ , NO, NO ₂ , ClO ₂ , and O ₃ . These paramagnetic gases can be removed from gas streams using the reagent used in the process of the invention, mainly

consist of (1) noble gases such as helium, argon or krypton, (2) inorganic gases such as carbon dioxide, Hydrogen and nitrogen, and (3) gaseous hydrocarbons such as lower alkanes, olefins, especially ethylene, propylene and butylenes.

Gas streams that contain up to 1000 or up to 5000 ppm of paramagnetic gases can with a Temperature, such as B. room temperature, at a rate of 2000 to 50001 per hour per Liters of reagent bed volume are passed over the reagent used according to the invention. Under these Conditions, the oxygen content of the gas flow is reduced to less than 10 ppm, preferably to less than 1 ppm. In general it is possible by using a higher weight percentage of reactive metal in the reagent and by using a lower flow rate through the reagent bed a more effective removal of the paramagnetic

10

15th

To achieve gases.

When the reagent is gradually depleted, i. H. loses effectiveness, the gas flow through the Reagent bed stopped or preferably passed through a valve over another reagent bed while The depleted reagent bed is regenerated by reacting the reactive metal with a Hydrogen stream or a hydrogen / nitrogen gas stream at a temperature of about 100 to about 400 ° G reduced.

The preparation of the reagent used according to the invention and the implementation of the inventive reagent The method is explained in more detail in the following examples.

example 1

(A) A portion of y-aluminum oxide with a content of 0.1 to 1.5 wt .-% Na ₂ O and a particle size of 1.0 to 2.38 mm was with an aqueous solution of copper (II) sulfate and Nickel sulfate, which contained 99 parts of copper per part of nickel, impregnated. The impregnated γ-alumina was dried and roasted, converting the metal salts to a light green mixed alumina-copper oxide which was in the form of a unitary phase. The roasted material was then treated with a nitrogen / hydrogen mixture. treated at a temperature of 290 ° C for about 3 hours to reduce the oxides to metal. The total metal content of the reagent obtained was 5% by weight. The BET surface area of the reagent formed was 215 m ² / g. The chemisorption capacity of the reagent for carbon monoxide was 1.1 cm ³ / g.

(B) 38.5 g of activated ^ -alumina with a content of 0.1 to 1.5% by weight Na2O and a particle size of 1.0 to 2.38 mm was impregnated with 14 ml of an aqueous solution containing the 8th , 7 g of Cu (NO ₃ J ₂ .3 H ₂ O and 0.89 g of AgNO _3. The impregnated aluminum oxide was dried for 1 hour at 110 ° C. and then roasted for 3 hours at 350 ° C., whereby a light green mixed oxide was formed by copper and aluminum, which was present in the form of a uniform phase, then the oxide was reduced at 290 ° C. with a nitrogen / hydrogen mixture to form an aluminum oxide 4> which was impregnated with black, finely divided metal 90% copper and 10% silver, the metal content of the reagent obtained being about 6.5% by weight.

(C) A portion of an activated γ-aluminum oxide with a content of 0.1 to 1.5% by weight Na ₂ O and a particle size of 1.0 to 2.38 mm was mixed with an aqueous solution of copper (II) nitrate and silver nitrate with a content of 4 parts copper per part silver impregnated. The impregnated aluminum oxide was dried for 1 hour at 110 ° C. and then roasted for 3 hours at 350 ° C., resulting in a light green mixed oxide of copper and aluminum which was present in the form of a uniform phase; a nitrogen / hydrogen mixture reduced to form an aluminum oxide which was impregnated with black, finely divided metal. The metal consisted of 80% by weight copper and 20% by weight silver. The metal content of the reagent was 6.8% by weight.

(D) 41 g of an activated γ-aluminum oxide with a BET surface area of more than 10 m ² / g, which contained 0.1 to 1.5% by weight of Na ₂ O and a particle size of 1.0 to 2.38 mm was impregnated with 12 ml of an aqueous solution containing 6.8 g of Cu (NO ₃ I ₂ · 3 H ₂ O and 5.45 g of Ni (NO ₃ I ₂ · 6 H ₂ O. The impregnated alumina became It was dried at 110 ° C. for 2 hours and then roasted at 350 ° C. for 3 hours, resulting in a light green mixed oxide of copper and aluminum which was in the form of a uniform phase Metals were carried out with hydrogen at 400 ° C. The reduced metal consisted of 2 parts by weight of copper to 2 parts by weight of nickel. The metal content of the reagent obtained was about 6.6% by weight.

These reagents have been used to remove oxygen from different gas mixtures under different conditions. The experimental conditions and the degree of removal are given in Table I below. _{The "factory N 2} " used in the table below was a technically produced nitrogen containing some moisture and finely atomized oil as well as about 2 to about 50 ppm oxygen.

The metal content of reagents A to D can optionally be doubled by adding the Alumina impregnated a second time, either (1) after roasting or (2) after the final Reduction or (3) after use. This second impregnation after roasting increases for example, in the case of the above reagent D, the metal content in the reduction to about 13% by weight.

Table I.

attempt

Reagent used

99% Cu. 1% Ni on

■ / -aluminium oxide-

carrier (a)

99% Cu. 1% Ni on

j'-alumina

carrier (a)

99% Cu, 1% Ni

y-alumina

carrier (a)

Hand- Tempera- Room-

door of the swinging

permanent gas tightness

Stromes

(h) ("C) (l / l / h)

64

0.75

25th

25th

25.5

O2 content O2 content Type of gas flow.
in the in the remarks
Charge. product

(ppm) (ppm)

500

500

500. 5 to 20

5000

Factory N2, the one with

3 l / min via a 350 ml

Bed was headed

Cylinder N2 + added O2

Cylinder argon

-location Reagent used Hand-held tempera Spatial G-2 Gehali O2 switch I. Type of gas flow. Ver lung ture of Schwin in the by doing Remarks search diiucr gas age Charge. product No. Stromes (H) CC) (l / l / h) (ppm) (ppm) 99% Cu, 1% Ni 48 25.5 500 90 _<} Ethylene / nitrogen 4th y-aluminum oxide mixture carrier (a) 22nd 25.5 500 90 1-15 Ethylene nitrogen Mixture contaminated with reduced reagent 99% Cu, 1% Ni 5 25th 500 55 <1 Cylinder H2 5 y-aluminum oxide carrier (a) 99% Cu, 1% Ni 25th -78 500 4 to 50 <i Factory N2 6th y-alumina carrier (a) 99% Cu, 1% Nt 19th -196 220 30th <1 H2 (inlet pipe and 7th y-alumina Reactor in liquid carrier (a) N2 cooled) 90% Cu, 10% Ag 16 25th 220 2000 <1 Factory N2 + added 8th y-alumina air carrier (b)

90% Cu, 10% Ag on y-aluminum oxide support (b)

90% Cu, 10% Ag on y-aluminum oxide support (b)

80% Cu, 20% Ag on activated y-aluminum oxide support (c)

60% Cu ₁ 40% Ni on activated y-aluminum oxide carrier (d)

60% Cu, 40% Ni on activated y-aluminum oxide carrier (d) 60% Cu, 40% Ni on activated y-aluminum oxide carrier (d)

45

1.5

26th

16

2.5

17.5

25th

25th

220

up to 50 <1

3000 <1

480 2000 0.15

480 2000 0.6

25th

3000 0.2

Metal content about 5%, preparation A, metal content about 6.5%, preparation B,

480 1000 0.1

c) Metal content about 6.8%, preparation C, ^f d) Metal content about 6.6%, preparation D.

Factory N2

Factory N2 + added air

Factory N2 + added

Ο2

Factory N2 + added air, 22 ml bed, 18 g reagent

Factory N2 + added air, 22 ml bed. 18 g reagent

Factory N2 + added air, 22 ml bed, 18 g reagent

example

This time, one of the reagents used according to the invention, as described in the above example under (C)

Table II. '

is used in experiments in which NO or NO2 was removed from a helium stream. the The results of these tests are summarized in Table II below.

Ver Used Treat Tempe Spatial 02 salary 02 salary Type of gas flow, search reagent lung rature of dizzy in the . ' by doing Remarks No. duration Gas flow speed feed product (H) ( ⁰ C) (l / l / h) (ppm) (ppm)

80% Cu, 200/0 Ag on activated y-alumina carrier (c)

1.5

25th

480

10,000
ppm NO

ppm NO

1% NO in pure He, some N2O formed

809 526/6

continuation

ίο

Ver Used Bchand- Tempe Room gc- O '- Gehali O.'- Gehnli Type of gas flow. search reagent lung rature of windy in the in the < . Remarks No. duration Gas flow speed feed product (H) ( ⁰ C) (l / l / h) (ppm) (ppm)

16 80% Cu, 20% Ag

on activated
y-alumina support (c)

25th

480 1000
ppm NO ₂

0.5 to 1.4
ppm NO2

NO + 1 / 2O2 in
stoichiometric
Amounts too pure
Helium added

Example 3

To further explain the preparation of the reagent used according to the invention and the method according to the invention, 10 g Ni (NO ₃ ) ₂ · 6 H ₂ O, 4 g Co (NO ₃ ) ₂ · 6 H ₂ O, 4 g Cr (NO ₃ ) ₃ 9 H ₂ O, 8 g of a 50% by weight Mn (NO _{3 I 2} solution in water and 1.0 g of AgNO _{3 dissolved} in an aqueous solution, which is made up of 100 ml of water and 10 ml of concentrated nitric acid (16 After the dissolution of the salts was complete, 280 g of Cu (NO ₃ ) ₂ · 3 H ₂ O were dissolved in the solution so that a total of 240 ml of impregnating solution was obtained. This impregnating solution was applied to 747 g of y-aluminum oxide The γ-alumina contained 1.18% by weight Na ₂ O. In addition, the γ-alumina had a BET surface area of about 177 m ² / g and a particle size of 1.0 to 2.38 mm 2 hours at about 160 ⁰ C dried, the dried material was then roasted at 400 ° C for 5 hours to obtain an olive green colored product was obtained in which at the X-ray examination could not detect a separate copper oxide phase. It was found that all of the metal oxides were in the form of a uniform phase.

Then 128 g of the dried and roasted impregnated alumina was molded of a bed in a column made of a piece of iron pipe with an inner diameter of 2.54 cm and 8 "long with retaining screens at the bottom and top and pipe connections at each end for passing various gases through the reagent bed contained therein. The pillar was also equipped with a heating device. A hydrogen stream that is about 90% by volume nitrogen was passed through the column while the impregnated alumina was at a temperature of 100 ° C was maintained. The reduction of copper oxide and the activator metal oxide to the metallic form was complete after about 30 minutes. Most of the reduced metal was in amorphous form, while smaller amounts were in crystallized form.

The reagent obtained was used in a number of approaches to demonstrate the high effectiveness and the large capacity of the reagent used in the present invention and the influence of temperature used to remove oxygen from a nitrogen stream during regeneration, the contained about 200 ppm oxygen. The nitrogen flow was at a flow rate of 33001 per 1 reagent bed volume per hour passed through the reagent bed Regeneration or reduction carried out at different temperatures.

Before the first approach, the reduction was carried out at a temperature of 100 ⁰ C. When the nitrogen / oxygen mixture was passed through the reagent for a period of 4 to 6 hours, the column effluent showed an oxygen concentration of less than 1 ppm. After 1 cm ^{3 of} oxygen per gram of reagent had been bubbled through the bed, the reagent still removed 90% of the oxygen from the nitrogen stream.

In a second run the reagent was regenerated at a temperature of 150 ° C and it was again passed through the nitrogen atom containing 200 ppm of oxygen at room temperature, the same Results as obtained in the first run.

In a third approach, the reagent was regenerated at a temperature of 200 ° C. As the oxygen-containing nitrogen stream was passed through the reagent, nearly 100% oxygen removal occurred until about 0.1 cm ^{3 of} oxygen per gram of reagent had been absorbed by the bed. After 1.25 cm ^{3 of} oxygen per gram of reagent was absorbed by the bed, the reagent still removed 98% by volume of the oxygen contained in the nitrogen stream. After absorbing 1.75 cm ^{3 of} oxygen per gram of reagent, the reagent bed removed 90% by volume of the oxygen contained in the nitrogen stream.

In a fourth approach, the reagent was regenerated at a temperature of 270 ⁰ C. The reagent obtained thereby removed practically 100% of the oxygen from the oxygen-containing nitrogen stream until 2.06 cm ^{3 of} oxygen per g of catalyst had been introduced into the bed. After 2.3 cm ³ of oxygen per reagent in the bed had been initiated, the reagent is removed for about 98% of the oxygen from the nitrogen stream. After 2.6 cm ³ oxygen were introduced into the Reagensbett per gram of reagent for about 90% of the oxygen from the nitrogen stream were always removed.

In the case of repeated regeneration, the behavior described was repeated even after 8 to 10 cycles same lot of reagent.

Example 4

In a further example to illustrate the reagent used according to the invention and the method according to the invention, a copper nitrate solution containing nitrates of activator metals was prepared in the same amount and in the same way as in Example 3 above. This impregnation solution was also distributed on 747 g ^ -alumina. The γ-alumina contained 0.29% by weight Na ₂ O. In addition, the γ-alumina had a BET surface area of about 163 m ² / g and a particle size of 1.0 to 2.38 mm. The impregnated alumina was dried as in Example 3 above and dried

roasted, whereby a single-phase mixed oxide with a light green color was obtained.

128 g of roasted impregnated γ- alumina were filled as in Example 3 above in a column and bei.einer temperature of 270 ⁰ C by passing a hydrogen stream comprising about 90 vol .-% nitrogen, 30 reduces minutes. The reduced material was oxidized by a nitrogen stream containing about 5 vol .-% of oxygen contained 30 was slowly passed minutes through the bed during the column and the reagent were maintained at a temperature of about 25 to about 5O ⁰ C. The reagent was then regenerated with the same hydrogen stream at a temperature of 270 ^° C. prior to use for removing oxygen from a nitrogen stream containing about 200 ppm of oxygen.

The nitrogen stream was passed through the reagent bed at room temperature at a rate of 3300 1/1 reagent bed / hour for 4 to 6 hours. The effluent from the column initially showed an oxygen concentration of less than 1 ppm. The deoxygenation efficiency did not fall below about 100% until 3.25 cm ^{3 of} oxygen per gram of reagent was introduced into the bed. The deoxygenation efficiency did not fall below 98% until 3.5 cm ^{3 of} oxygen per gram of reagent was introduced into the bed. It was only after 4.0 cm ^{3 of} oxygen per gram of reagent had been introduced into the bed that the oxygen removal efficiency fell below 90%.

Example 5
(Comparative example)

In further experiments, carried out using the procedure described in British Patent 835751, a reagent consisting of copper dispersed on a magnesium silicate support was used. The copper content of the material was 24% by weight when the material was in the oxidized state. The material consisted of uniform tablets with a diameter of 5 mm and a length of 3 to 8 mm. The bulk density of the material was 1.1 g / cm ³

This comparative material was filled in the method described in Example 3 iron pipe and reduced hydrogen stream having the indicated nitrogen /, while the material was maintained at a temperature of 15O ⁰ C. After the nitrogen stream containing 200 ppm of oxygen was introduced into the bed, the efficiency of oxygen removal dropped sharply from 100% to 90% and less. The comparative reagent removed only 90% of the oxygen from the nitrogen stream after only 0.1 cm ^{3 of} oxygen per gram of reagent had been introduced into the bed.

After the comparison material had been regenerated at a temperature of 270 ^° C., the effectiveness of the oxygen removal fell to 98% by volume after only 0.1 cm ^{3 of} oxygen per g of reagent had been introduced into the bed. The efficiency of removal of the control material fell to 90% after only 0.34 cm ^{3 of} oxygen per gram of material had been introduced into the reagent bed.

From the above-described inventive examples 3 and 4 and comparative example 5, it can be seen that the absorption capacity and the cleaning power of the reagent used according to the invention were clearly superior to the reagent known from British patent 8 35 751. While in example 3 according to the invention, depending on the regeneration temperature used, 1 to 2.6 cm ^{3 of} oxygen per gram of reagent were required in order to reduce the efficiency of oxygen removal of the reagent used according to the invention from 100% to 90%, and in example 4 according to the invention 3.25 cm ^{3 of} oxygen or 4.0 cm ^{3 of} oxygen per g of reagent were required in order to reduce the efficiency of the oxygen removal of the reagent used according to the invention from 100% to 98% or 90%, in Comparative Example 5, 0 was sufficient. 1 to 0.34 cm ^{3 of} oxygen per g of reagent in order, depending on the regeneration conditions, to reduce the degree of oxygen removal of the reagent known from British patent 8 35 751 from 100% to 90%.

Claims (3)

Patent claims: 1. A method for reducing the content of a gas manure of paramagnetic gas by passing the gas mixture over a particulate reagent kept in a closed zone and consisting of finely divided, in situ reduced copper by an _{aluminum oxide carrier containing Na 2} O, characterized in that a Reagent is used which consists of 3 to 13 wt .-% copper on a γ- alumina support with 0.1 to 1.5 wt .-% Na2O, based on the alumina support, and a surface area of at least 10 m ² / g and the particles of which have an average diameter of 1.0 to 2.38 mm. 2. The method according to claim 1, characterized in that a reagent is used which in addition to the reduced copper, an activator metal from the group silver, platinum, palladium, Contains manganese, nickel, cobalt, chromium and / or molybdenum in an amount that is up to 45% by weight of the Total weight of copper and activator metal can be. 3. The method according to claim 1 or 2, characterized in that the paramagnetic to be reduced Gas is oxygen.