DE2149855A1 - Method for stabilizing a catalyst - Google Patents

Description

Patent assessor Hamburg, 5-10.1971

Dr. Gerhard Schupfner .0? 71 045 (D 71) German Texaco AG. YH / Wd.

2000 Hamburg 76
Sextuple gate 2

TEXACO DEVELOPMENT CORPOEATION

135 East 42nd Street

New York, N.Y. 10017

UNITED STATES.

Method for stabilizing a catalyst

The invention relates to the manufacture of catalysts. In particular The invention relates to the stabilization of improved carbon catalysts with metals from Group VIIB and VIII of the PSE, the catalysts having stabilized activity and improved crush resistance.

Metals of Groups VII B and VIII of the PSE are used as catalyst components and are of interest in a variety of processes including hydrogenation. Various production methods for these catalysts have heretofore been proposed. Usually the hydrogenation catalysts various formulations, the catalytically active metal from group VII B or VIII represents only a small part of the catalyst and various types of support, such as carbon, Aluminum oxide, SiOp, aluminosilicates and the like. The support, as part of the heterogeneous catalyst, can be a welcome activity and in many cases initially

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have mechanical strength. But as well as water, which as a by-product of hydrogenation reactions with organic compounds occurs, is present, the heterogeneous catalysts easily begin to. soften, leading to a decay of the Catalyst or leads to poisoning at relatively low process temperatures. Progressive deactivation occurs a, making the currently available catalysts useless for economical processes.

The invention now provides ν orliegende catalytically active mixture prepared which w Katalysatorlebens- a longer period, having stabilized activity and high crushing strength.

This invention provides a method of making a Long-life catalyst, the catalyst being treated in a stabilization step which is the catalytic Activity not adversely affected.

The invention also relates to a hydrogenation process which, in the presence of a catalyst, has a stabilized activity and high crushing strength is performed.

The invention relates to a process for the stabilization) that at least one hour at 260 the catalyst tion of a catalyst, which contains on a carbon support is a metal of Group VII B or VIII of the PSE, characterized !, - 649 ⁰ C in the presence of not a oxidizing gas is heated.

Another feature of the invention relates to low temperature hydrogenation nitrated or oxidized Cg - C ^ - hydrocarbons to the corresponding amines and alcohols by adding hydrocarbon and hydrogen with a catalyst in Contact ', f., Where a metal from Group VII B or VIII of the PSE on carbon heated for at least one hour at 260-649 ° 0 in the presence of a non-oxidizing gas irird

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A preferred feature of the invention is the preparation of primary amines with secondary alkyl groups by reaction secondary mononitroparaffins with hydrogen in the presence of a palladium-carbon catalyst, according to the above Executions was stabilized.

The stabilized catalysts of the invention contain about 0.1-1o% by weight of a metal from group VII B or VIII, preferably 0.5-2.0% by weight, which is based on activated carbon is dejected. Examples of the metals considered jxhenium, palladium, rhodium and ruthenium. Metal combinations, e.g. platinum-rhenium, are also contemplated.

Activated carbon as a component of the heterogeneous Catalyst is a class of well-known materials, usually made up of coal, petroleum coke, as well as animal and vegetable Material to be made. The raw material is first heated to 316 - 64-9 ° C in a non-oxidizing The atmosphere is charred and then in a gas stream that contains small amounts of air or superheated steam, activated at 649 - 927 ° C. In addition, for enlargement of pore volume and surface area during activation of oxygen placed on the carbon surface, the resulting different shape, referred to as surface oxides, accepts. The carbon surfaces partially oxidized in this way are hydrophilic and promote the wetting of the activated carbon with aqueous impregnation solutions that are a Group VII B and VIII metal.

In a special embodiment of the invention, an ash content of the activated carbon of less than 5% by weight, especially below 2% by weight, preferred. Activated carbon with an ash content below 5% by weight represents a class commercially available materials, which are used as water treatment agents and absorbents for low molecular weight hydrocarbon

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gases are known. The ash content of the activated carbon is determined by burning the carbon in red heat, being an inorganic oxide residue consisting of silicon, aluminum, iron, calcium and magnesium, as well as traces Titanium, sodium and sometimes nickel and vanadium is obtained. It is also known to use the activated carbon Acid, for example HCl, to treat to achieve an ash content below 2 wt .-%, with the majority of the remaining inorganic oxide, SiÜ2 is. In general the activated carbon described and used as a catalyst support is suitably tableted or extruded Form used. The activated carbon, which forms the support of the heterogeneous catalyst, and according to the invention Process is stabilized, has a large surface, with about 800 - 1400 m / gr. are typical.

To produce the stabilized heterogeneous catalysts, the activated carbon is mixed with an aqueous salt solution impregnated. For example, a metal, e.g. B. platinum, by treating the activated carbon with a aqueous solution of chloroplatinic acid and ethylenediamine applied to the carrier. If a palladium catalyst is considered, drawn ', an aqueous solution of Palladium chloride or palladium nitrate to the activated carbon. After thorough mixing of the impregnation solution and Carbon is dried at 93 - 121 ° C and the result is a catalytically active platinum or palladium on carbon in the mixture. Similarly, other Group VIII metals such as rhodium. And ruthenium, and metals of Group VII B, such as rhenium, introduced, whereby the heterogeneous catalyst is impregnated and for the subsequent invention Stabilization is available.

The mixture produced in this way, which initially has a high catalytic Has activity and a tendency to crush, if it is used as a hydrogenation catalyst, it loses

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continues its activity within a short time because the mixture is exposed to water, a reaction by-product. It has now been found that by heating the catalyst for at least one to 24 hours, preferably 2-8 Hours, at 260-649 ° G, preferably 371-595 ° C, in a non-oxidizing atmosphere a catalyst with stabilized Activity and extended crush strength is obtained. It is believed that this treatment the proportion of surface oxides is reduced and removed and a more hydrophobic catalyst characteristic is made possible. A variety of non-oxidizing gases are applicable, e.g. B. Nitrogen, methane, argon, helium, neon, ethane and propane. In a particularly preferred embodiment, there is the non-CKidende Atmosphere of hydrogen or mixtures of hydrogen and light hydrocarbons. The latter mixture can be obtained, for example, as exhaust gas from a catalytic reformer system. The preferred atmosphere, before especially the reducing atmosphere of hydrogen, leads to superior catalyst properties, which are prolonged in a and increased catalyst activity, especially after treatment at 371-593 ° C., when used in hydrogenation reactions which produce substantial amounts of water as a by-product. In general, the

m
heating / a non-oxidizing atmosphere at pressures of 0-70.3 kg / cm, preferably 21.1-49.2 kg / cm ^. Conversely, oxidizing conditions, for example in the presence of air or oxygen, during heating lead to rapid softening of the catalyst prior to its use and to deactivation when the catalyst is used in water-forming reactions.

One method of catalyst development is that a non-oxide gas is poured over and through the catalyst bed at the above temperatures. Dr-.I- · 'ori flows _s wherein the gas with a Geschwind if- ^ eib "ni-u ^ in t -us ο, -icf / ikr per above, Oy

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BATH ORIGINAL

Reactor cross section and hour (50 SCF per hour per square foot of reactor cross section) at least one hour, preferably 2-8 hours.

The metals stabilized on the carbon catalyst of Group YII B or YIII of the PSE are particularly for use as hydrogenation catalysts in low temperature conversion reactions at temperatures of 37 »5 - 232 ° C, hydrogen pressures from 10 - 300 atmospheres and space-time velocities (RZG, liquid hourly space velocities) from 0.2 - 20 suitable, by reducing the amount of nitrated or oxidized Cg C25 hydrocarbons paraffinic or olefinic nature to amines and alcohols with formation of water as a by-product is carried out. Hydrogenations using the stabilized catalysts include the reduction of mononitroparaffins su primary amines with secondary alkyl groups and secondary amines with secondary alkyl groups, oxyiaen to amines, nitroolefins to amines, fatty acids to alcohols and nitro ketones, ifitro alcohols and ifitronitrates to form amino alcohols.

In a preferred medium temperature reaction in which the stabilized catalyst is used to prepare primary amines with secondary alkyl groups, a mononitroparaffin with 6-2.5 carbon atoms is reacted with hydrogen. Mononitroparaffins contemplated in this manufacturing process relate to secondary nitro-n-paraffins in which a nitro group is attached to any carbon atom of a carbon atom but not to a terminal carbon atom _t . Inen to these Mononitroparaff include 2- or 3-NitrohexaE .. 2-, 3- or 4-lTitroheptan, 2 ™, 3- or 4-KItrooktan, 2-, 3-, 4 ~ or _5-3 Hitrodecan j _2; 3- » ^li ~ * 5- or 6- hitroundecane, 2», 3-j ^ -. 3- or 6-2Titro & odecani 2-, 3-, 4- ~ i _'} 5- 6- or 7-Witrotrid ECAN, 2-, 3-, 4-, 5- _{Ϋ 5} 6- or 7-NitiOtetradeean, 2, _J .- _s 4 =. _; 5- »6-, 7-j Q ~ or 9-nitrooctadecaii and Hischu ^ geii cLsrBol- · hen, z. B. rlit'chungeri from ' ^! , _ί} - Ο ^^ - ΠΙυΓορί, Γ ^ ΓΕιι ^ ϋ. The? M-

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BATH ORIGINAL

reversible mononitroparaffins are made by. Reaction of a paraffinic Cg-025 hydrocarbon, preferably one straight-chain hydrocarbon, in liquid phase with a vaporous nitrating agent, such as. B. nitrogen dioxide or nitric acid, made at about 121-260 ° C and 1-20 atmospheres.

This nitration reaction can be carried out either batchwise or continuously until about 5 - 50 % of the paraffin in nitrated crude product, which is about 5 - 4-5 % mononitroparaffin and 95 - 50 % unconverted paraffin together with small amounts of Cg-Coc- Contains ketone, alcohol, carboxylic acid and polyfunctional compounds. The mononitroparaffins produced in this way can, if desired, be separated off and obtained from the crude product by distillation and converted into the corresponding amines in a subsequent hydrogenation. The reaction is usually carried out in the presence of paraffinic Cβ-C ^ hydrocarbons as a diluent. On the other hand, the raw material can be nitrided directly, with unreacted paraffin forming the reaction medium. The nitrated crude product can also be washed with alkaline to remove acidic by-products formed in the nitration, e.g. B. with sodium bicarbonate, ammonium hydroxide, sodium hydroxide or potassium hydroxide. If the nitroparaffin starting materials are essentially free of acidic by-products or impurities, the neutralization can be omitted.

In a preferred embodiment, the nitroparaffins are used to primary amines with secondary alkyl groups in the presence of a stabilized metal-carbon catalyst about 37 * 5 - 232 ° C and under hydrogen pressures of about 10 300 Atmospheres, preferably 20-40 atmospheres. The reaction is exothermic and temperatures exceeding 232 ° C have a detrimental effect on the formation of primary amines. The formation increases at temperatures above 232 ° C

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secondary amines strongly. If secondary amines are required alone or in a mixture with primary amines, stabilized amines can be used Platinum or rhenium carbon catalysts are more useful Veise shift the selectivity in this direction. The proportion of nitroparaffin based on the amount of catalyst is subject no restriction and optimal proportions can be quickly determined through experiments. The general rule is that, ever greater the ratio of catalyst to nitro compound is to the faster the reaction takes place.

It was found that the use of palladium compared to a greater selectivity in the formation of primary amines leads to the formation of secondary amines and comparatively other metals used in the process according to the invention can be used.

The process described can be carried out batchwise or continuously. Suitable reactors are charged, pressed off, preferably stirred and the progress of the reaction monitored by the hydrogen pressure. Alternatively, you can also continuous processes are chosen, with the nitro paraffin through and over the catalyst in the presence of hydrogen and under the pressure and temperature conditions already mentioned and RZG of about 0.2 - 20 Vol.Aol./h flows »

Customary extraction processes can be used to extract amines become, such as B. the distillation of the crude reaction product by gradual fractionation. on the other hand the amine can first be reacted with an inorganic acid, then obtained as an amine salt by further treating the salt the amine is released with alkali and then distilled to obtain it. Those produced in this way Amines are used as mold release agents, emulsion anti-icing stabilizers, Pigment dispersants, polyurethane catalysts, and anti-caking and anti-dust agents Use. They are also used as corrosion inhibitors, monitoring

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agents for harmful bacteria, sludge dispersers and useful as detergents and deicers in gasolines.

The hydrogenation reactions shown above at about 37-5 232 ° O, under hydrogen pressures of 10-300 atmospheres, ECG of about 0.2-20.0, and with longer flow times can lead to partial catalyst deactivation. The catalyst regeneration can be achieved easily by a non-oxidizing gas flow, preferably hydrogen, under the stated for the initial stabilization time and temperature conditions over the catalyst flows' ¹ and the catalyst activity -is remade again. the initial heating and subsequent regeneration may in situ, in the conversion reactor to be executed.

The following examples are provided to further illustrate the invention and to carry out the process according to the invention specified.

Example I;

A mixture of palladium on activated carbon was made by dissolving 10 grams of palladium chloride in 100 cc of water, 100 cc of concentrated ammonium hydroxide and 400 cc of methyl alcohol, adding this solution at Ö ° G to 594 grams of commercially available extruded activated carbon tablets (4 mm) and vigorous 1- stirring the mixture for hours. The solid particle wurdÄ separated ^ul Ä.tration, ° G for 16 hours and then heated for 6 hours in a stream of nitrogen to 104.4 ° C at 57.2. 57 ^ grams of catalyst with 0.97 wt.% Palladium on the activated carbon were recovered.

A 54 gram sample of this catalyst was treated at 232 ° C in a 2.54 cm diameter reactor for 4 hours in a stream of hydrogen at a rate of 0.0283-0.0566 V at 42.2 kg / cm _v - catalyst A.

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Two additional 54 gram samples of the catalyst were heated to 566 ° C. for 4 hours in a stream of hydrogen at a rate of 0.0283-0.0566 mVh. "Had _/ heated at 4-2.2 kg / cm ² - Catalysts B and C.

An O / jQ - C ^ starting material with 14.6% by weight nitrated normal paraffin, 82.1% by weight normal paraffin, 0.4 % by weight ketone and 2.9 % by weight " bifunctional paraffin was won at a rate 100 grams / hour into a hydrogenation reactor containing the 54- gr. of catalyst a, and in a further hydrogenation reactor containing 5 $ / C catalyst, eilgegeben, wherein in each reactor 135 ⁰ C and a pressure of 42.2 kg / cm ² H2. The product analysis after a flow time of 60 hours showed that the catalyst A had lost 11% of its activity between the 12th and 48th hour. The catalyst C used under the same conditions showed its stabilized activity, which had decreased by only 4% in 12-48 hours during the conversion of nitroparaffin to primary amine;

The Cjo - C ^ nitrated paraffin starting material was placed in a heater containing 54 g of Catalyst C at 135 ° C, a hydrogen pressure of 42.2 kg / cm ² and a hydrogen flow rate of 0.04-0.0566 mVh. , entered at a rate of 130 grams / hour. Catalyst C shows no deactivation after 80 hours.

Example II:

A mixture of palladium on activated carbon was prepared by dissolving 6.7 palladium chloride in 70 cc water to which 100 cc ammonium hydroxide and 240 cc methyl alcohol had been added * This solution was added to 490 grams of a commercially available activated carbon in tablet form (3.27 mm ) and an ash content of 3 "iH wt" -95. · The mixture was ^{stirred vigorously at 0} ° C. for one hour, the solids then separated off by filtration and at 104.4 ° C.

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Dried for 4 hours in a stream of nitrogen. The catalyst contained o.92 wt .-% palladium (based on the chemical analysis) on the activated carbon catalyst D. The crush resistance was 6.485 kg / and was determined to be

the / force measured vnirde, which is necessary to the catalyst tablet to grind between two parallel plates.

A 57 gram sample of catalyst C was in a reactor, diameter 25 »4 mm, at 260 ° C for two hours in a hydrogen stream of the rate 0.04-0.0566 mVh. and 42.2 kg / cm ² heated - catalyst E.

Another 58 gram sample of Catalyst D was heated to 510 ° C for 2 hours in a stream of hydrogen at 0.028J - 0.0566 m3 hours and 42.2 kg / cm ² - Catalyst F.

A C] Q - C ^ starting material, see Example I, was made at a rate of 125 cc / hour. in a hydrogenation reactor, which contained 60 grams of the catalyst D, and in another hydrogenation reactor, which contained 57 grams of the catalyst E, entered, in each reactor 135 ° C and a V / a he st off pressure of 42.2 kg / cm was maintained. Product analysis of the feed treated with Catalyst D indicated that the catalyst had deactivated rapidly during on-flow and lost 11 % of its activity between the 8th and 28th hour of flow. The product analysis of the starting material treated with catalyst E showed that the catalyst had lost no activity during the 40 hour flow time.

58 grams of Catalyst F were processed in a similar manner with starting material treated, with the material being

speed of 125 cc / hour at 135 C. The catalyst F showed no deactivation within the flow time and product analysis showed its high selectivity

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from that 9.7 milliequivalents of primary amine per gram Product along with a negligible amount of secondary amine were formed. Were the procedural conditions for catalyst F at 107.2 ° C and 60 cc / hour. Changed liquid flow resulted again at high conversion no deactivation within the flow time. The crush resistance Catalysts E and F were measured after they had been used and values of 9.07 and 7.26 kg.

Example III;

1800 grams of commercially available activated carbon in tablet form, 3.27 mm in diameter, with an ash content of 3.51% by weight were mixed with 5 liters of a solution made by mixing 3 volumes of concentrated HCl with 7 volumes of water . After the material had digested for two hours at 60 ^° C., the activated carbon was filtered off and the solid particles were washed with water until they were free of chloride ions. The ash content of the dried acid-treated carbon was 1.37% by weight and the ash consisted mainly of SiO ₂ together with small amounts of iron, magnesium, calcium and titanium.

To the dried activated carbon, 25.7 grams of palladium chloride in 200 cc of concentrated ammonium hydroxide, 140 cc of water and 1000 cc of methyl alcohol are added. After thorough mixing, the separated solids were dried at 60 ° C in a stream of nitrogen. The following was a sample of the catalyst at 371 ° C. for 4 hours in a stream of nitrogen at atmospheric pressure heated. The catalytic material had a palladium content of 1.08% by weight and a crushing resistance of 9.07 kg.

A C ₇ Jq - C ^ starting material ^ according to Example I, flowed at a rate of 88 cc / hour. in a reactor, the 4-1

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Grams of catalyst contained and a temperature of 98.9 104.4 C and a hydrogen pressure of 42.2 kg / cm. Product analysis indicated 4.4 milliequivalents per gram of product of primary amine and no secondary amine. Became the reactor temperature increased to 138-143 ° C and the Speed of the starting material to 140 cc / hour. increased, the product analysis showed 5 »3 milliequivalents of primary amine and 0.2 milliequivalents secondary amine.

Another catalyst sample was heated to 371 ° C. under nitrogen and then treated at 510 ° C. for 2 hours in a hydrogen stream at a rate of 0.0283-0.0566 tsP / h and 42.2 kg / cm hydrogen pressure. Again, the G * q - C ^ material was entered at a rate of 85 cc / hour. into a reactor containing 40 g of catalyst, a temperature of 98, 9-104.4 ° C and an E ^ pressure of 42.2 kg / cm ² . Product analysis gave 5 »0 milliequivalents of primary amine per gram of product and 0.1 milliequivalents of secondary amine. By increasing the reaction temperature to 138-143 ° C and the inflow rate of the starting material to 140 cc / hour. 6.7 milliequivalents of primary amine and 0.2 milliequivalents of secondary amine resulted.

Another 400 gram sample of catalyst was heated at 371 ° C. nitrogen) and placed in a reactor in such a way that the catalyst formed a bed 254 mm deep in the reactor. Starting material flowed with an RZG of 0.50 and hydrogen with 0.283 m3 / h. under an H ₂ pressure of 40.8 kg / cm ² and a temperature of 149-177 ° C in the bed. The reaction was carried out over six weeks and gave the following result:

At the end of week 1, 9 »4 milliequivalents were primary Amine and 0.9 milliequivalents of secondary arain, in the 2nd week 9 »3 or 0.5 milliequivalents of the two amines, in the 3 · Week 9.4 and 0.4 milliequivalents of the two amines and in

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the 6th week 8.9 and 0.4 milliequivalents of the two amines were formed.

From this it can be seen that when the catalyst is heat treated, increased activity and selectivity in the conversion of microparaffin to primary amine is achieved with minimal formation of secondary amine. After 6 weeks, the catalyst surprisingly had an increased crushing strength of 10.3 kg and demonstrated a high selectivity of 92 % in the formation of primary amine from microparaffin.

Example IV;

Another catalyst was prepared according to Example III and contained 0.97% by weight of palladium on activated carbon, which had an ash content of 1.84% by weight and a surface area of 1.288 m / g. exhibited. 337 grams of this catalyst, which had been heated to 371 ° C. under nitrogen, were placed in a hydrogenation reactor and starting material B1 (see Example I) at a rate of 1.1 volumes of liquid per 0.45 kg of catalyst and hour under an E ₀ pressure of 42.2 kg / cm and a ^ speed of 0.283 m3 / h. introduced. The initial crushing strength of the catalyst was 8.16 kg and after a contact time of 804 hours was determined to be 9 »385 kg. From the data given below it can be seen that the catalyst boron remained active for 804 hours and constant primary amine formation was obtained over this period. Secondary amine formation decreased, resulting in a higher selectivity for primary amine. The results of the following table are given / milliequivalents of amine per gram of product:

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primary amine secondary 8.9 1.1 9.1 0.9 9.2 o, 7 9.3 0.7 9.2 0.7 8.9 0.6 9.0 0.6 9.2 0.5 9.2 0.6 8.9 0.5

_ ₁₅ _ 2U9855

hours

72 114 246 390 525 804

After 804 hours of process time, the supply of nitroparaffin was interrupted and the catalyst was heated in situ in a B ^ stream, 0.283 m * / hour, at 42.2 kg Hg / cm ² , 482 ° C., for 4 hours. This action served to regenerate the catalyst by removing the deposits on it. The catalyst was then brought into contact again with the starting material under the conditions already described. From the following results it can be seen that the catalyst had not only become more active after the regeneration treatment, but also had a controlled selectivity, since the formation of primary amine was increased and that of the secondary amine was reduced after comparable flow periods. The results in the table below are given in milliequivalents of amine per gram of product.

Hours primary amine secondary amine

6 9.2 0.9

12 9.7 0.5

24 9.8 0.4

36 9.8 0.4.

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Example V:

Two catalysts, palladium 1% "or 1% platinum on activated carbon, were at 482 ⁰ C in a stream Ho, 0,0J? 66 mVStunde, at an H ₂ pressure of 42.2 kg / cm ² 3 hours 20 g (50 cc) of each catalyst was placed in a hydrogenation reactor and starting material, 16 wt% ^ λγΓ C ^ -nitroparaffin in a C ^ QC. ^ - n-paraffin, combined at a rate of 30 cc / hour with hydrogen, 0.0481 mVßtunde, 42.2 kg / cm ² H ₂ pressure flowed at 149 ⁰ C in the reactor. the Produktanlayse for each reactor the higher selectivity exhibited by the palladium catalyst in the "formation of primary amines containing secondary alkyl groups. 8.3 milliequivalents of primary amine had been formed per gram of product, while the use of the platinum catalyst resulted in 4.8 milliequivalents. The use of the platinum catalyst resulted in twice the amount of secondary amine compared to the palladium catalyst. If the total equivalence is calculated as the primary amine, the result for the more active palladium catalyst is 11.1 milliequivalents compared to 10.4 milliequivalents for the platinum catalyst.

Example VI:

\ A catalyst having 2 wt .-% rhenium on activated carbon was prepared by impregnating the carbon with perrhenic acid, which was dissolved in dilute ammonium hydroxide, followed by drying at 104.4 ° C for 4 hours under nitrogen atmosphere prepared. As in the example of the catalyst to 482 ⁰ C in a Hp-current 0.0566 mVstunde, an H ₂ pressure of 42.2 kg / cm ² for 3 hours was heated. 20 grams (50 cc) of the catalyst were fed to a hydrogenation reactor and treated with starting material and under the conditions of Example V for 24 hours. The product analysis showed the higher selec-

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activity of the rhenium catalyst in BiMing secondary Amines with secondary alkyl groups by adding 4.1 milliequivalents secondary amine and 3 »4- milliequivalents primary Amine were formed. The total equivalence calculated as the primary amine gives * 11.6 milliequivalents for the very active ehenium catalyst

Example VII:

Further catalyst investigations were carried out by hydrogenating a CQ-C ^ -nitroparaffin starting material, · according to Example I, with a commercially available nickel catalyst on kieselguhr in tablet form, 4.76 mm in diameter, at temperatures between 182 and 90.5 ° C. Dissolved nickel was detected in the reactor effluent in significant amounts at temperatures below 149 ⁰ C, and there was a sharp rise Nickeleluierung when the reaction temperature was continuously reduced to 90 "5 ⁰ G. The ppm nickel amounts were detected in the product at the following reaction temperatures:

182 C less than <t 163 ° 0 -1 149 ° C -1 93.3 ° C -14 90.5 ° C -31

In another study, 755 g (620 cc) nickel catalyst was used on kieselguhr at temperatures of 157-196 ° C with starting material according to Example I, speed 1.675 kg / hour, and hydrogen, pressure 42.2 kg / cm and speed 0.283 mVhour implemented. As milliequivalents for primary amine and secondary amine, each with secondary alkyl groups the following results were found for longer flow times:

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primary amine 2149855 hours .8.9 secondary amine 63 8.6 0.66 96 7.8 0.5 144 7.0 0.57 207 6.6 0.5 258 0.5

From this it can be seen that under process conditions which favor little or no spot solubility in the amine product, the catalyst activity steadily decreases.

Another noble metal catalyst with 0.6 wt .-% platinum on eta-aluminum oxide, which had a crushing strength of 7.26 kg, was used in the hydrogenation of a starting material according to Example I and the starting material flowed at 94 cc / hour at 107, 2 ⁰ C, a H _o pressure of 42.2 kg / cm and an RZG of 1.0 into the beactor. After a flow time of 108 hours, the crushing strength of the catalyst was 1.36 kg.

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Claims (1)

2U9855 19 - O? 71 04-5 (D Claims 1. A method for stabilizing a catalyst which is a metal of group VII B or on a carbon support VIII of the PSE, characterized in that the catalyst contains at least 1 Hour to 260 - 649 ° C in the presence of a non-oxidizing Gas is heated. 2. The method according to claim 1, characterized in that the non-oxidizing gas is hydrogen or nitrogen is introduced. 5. The method according to claim 1 or 2, characterized in that the non-oxidizing gas is added ^{to the catalyst at a rate of at least 0.127 Nm 5} per 0.09 m ^ beactor cross-section and hour for 2-8 hours. 4-. Method according to claim 1, characterized in that that worked with a carbon catalyst which has an ash content below 5.0% by weight will. 5. The method according to claim 1 and 4-, characterized that with a carbon catalyst, which has a surface of about 800 - 1400 m / Gram, is worked. 6. The method according to claim 1, 4 und.5, characterized in that worked with a catalyst which has a metal content of 0.1-10% by weight will. 209820/1037 ²⁰ - 2U9855 7 · Method according to one of the preceding claims, characterized in that with. Rhenium, platinum, palladium, rhodium or ruthenium is worked. 8. Use of a catalyst prepared according to one of the preceding claims for the hydrogenation or nitrated oxidized hydrocarbons under · hydrogenation conditions and at 37j5 - 232 ° C with formation of amines and alcohols with 6-25 carbon atoms. 9. Use according to claim 8, characterized in that the formation of primary amines with secondary alkyl groups by heating a secondary mononitroparaffin with 6-25 carbon atoms in the presence of a stabiliäerten palladium-carbon catalyst is carried out. 10. Application according to claim 8 or 9 »characterized by g e that hydrogenation pressures of 10-300 atmospheres are used. 11. Use according to claim 9i, characterized that with secondary cononitroparaffins, which have 10-14 carbon atoms, is worked. 209 & 2O / T037