MXPA97004756A - Preparation of alpha, w- aminonitrilos alifati - Google Patents

Abstract

The present invention relates to a process for the preparation of aliphatic alpha-w-aminonitriles by the partial hydrogenation of aliphatic alpha-w-dinitriles at elevated temperatures and atmospheric pressure in the presence of a solvent and a catalyst, the process comprises the use of a catalyst which (a) contains a compound based on a metal that is selected from the group consisting of nickel, cobalt, iron, ruthenium and rhodium, and (b) contains 0.01 to 25% by weight, based on ( a), of a promoter based on a metal that is selected from the group consisting of palladium, platinum, iridium, osmium, copper, silver, gold, chromium, molybdenum, tungsten, manganese, rhenium, zinc, cadmium, lead, aluminum, tin, phosphorus, arsenic, antimony, bismuth, silicon titanium, zirconium and rare earth metals, and (c) from 0 to 5% by weight based on (a), of a compound based on an alkali metal or an alkaline earth metal , with the proviso that the component (a) is not based on hier or iron and one of the metals selected from the group consists of cobalt, ruthenium and rhodium, when (b) is a promoter based on a metal that is selected from the group consisting of titanium, manganese, chromium and molybdenum, and also with the proviso that, when a compound based only on ruthenium or rhodium or ruthenium and rhodium or nickel and rhodium is selected as component (a), the promoter (b) may, if desired, omit

Description

PREPARATION OF a,? - aminoni trifas alipáticos The present invention relates to an improved process < for the . preparation of aliphatic a,? - aminonitriles by the partial hydrogenation of aliphatic α, β-dinitriles at elevated temperatures and superatmospheric pressure in the presence of a solvent and a catalyst. WO 92/21650 discloses the partial hydrogenation of adiponitrile to 6-aminocapronium in the presence of Raney nickel catalyst and ammonia as a solvent in a yield of 60% in a conversion of 70 ?. 9% hexamethylenediamine was formed as a by-product. The disadvantage of this process is the short life of the catalyst. US Patents 2,257,814 and 2,208,598 of l ") likewise describe the processes for the preparation of 6-aminocapronitrile starting from adiponitrile, the catalysts being used are Raney cobalt or iron, nickel and cobalt catalysts on various carriers. 50 a> 0 ¥,, the are too low for industrial applications, r < ^ a disadvantage of these processes. In the process of WO 93/16034, it is possible to increase? * > 'yield of aminocaproni thiol by the hydrogenation of adiponitrile in the presence of the Raney nickel catalyst, of a base such as sodium hydroxide, potassium hydroxide, lithium hydroxide or ammonium hydroxide, and a transition metal complex containing, for example, iron, cobalt, chromium or tungsten as transition metals, and a solvent In this process, aminocapronitrile quantitative yields are obtained in conversions from 45 to 60%. The disadvantage of this process is the handling of the generally toxic transition metal complexes from the reaction mixtures obtained. EP-A 161,419 describes the partial hydrogenation of adiponitrile using rhodium-containing catalyst on a magnesium oxide carrier. At a conversion of 70 [mu], a selectivity of 94 [mu], is achieved. The disadvantage is the costly preparation method for Rh / MgO catalysts is disadvantageous (see see J. of Cat. 112 (1980), 145-156). DE-A 4, 235, 466 discloses the fixed bed hydrogenation of adiponitrile to 6-aminocaproyroyl on an iron sponge catalyst (catalyst without support) which was prepared from iron ore by special method and subsequently contaminated with cobalt, titanium, manganese, chromium, molybdenum, ruthenium, or iridium. Due to the small surface area (0.8 mVg), these catalysts usually have useful activity only high pressures and elevated temperatures. Another disadvantage)! of this process is the rapid loss of activity to prr-i 'of a reduction in adiponitrile and hydrogen loading, which gives rise to an increase in conversion, according to example 7 the conversion decreases 5% in the course of 24 hours. Patent EU-A 848, 654 describes the hydrogenation of continuous fixed bed of adiponitrile on palladium on silica gel and on metals of group 8 of the Periodic Table, these metals are preferably used in the form of spinels. A substantial disadvantage of these catalysts is their unsatisfactory half-life. An object of the present invention is to provide an improved process for the preparation of aliphatic α, β-ammonitriles by partial hydrogenation of adiponitriles, said process does not have the aforementioned disadvantages, in particular, a process is proposed in which the catalysts which are They have a longer life, than those of the prior art. We have found that this objective is achieved through in, process for the preparation of a,? -ami noni tri aliphatic p By partial hydrogenation of a, (? - dinitri the aliphatics at elevated temperatures and physical superatmospheric pressure in the presence of a solvent and a catalyst, the process comprises the use of a catalyst which: (a) contains a compound based on a metal quo is selected from the group consisting of nickel, cobalt, iron, ruthenium and rhodium, and (b) contains from 0.1 to 25, preferably from 0.1 to 5 ?. by weight based on a promoter based on a metal that is selected from the group consisting of palladium, platinum and lithium, osmium, copper, silver, gold, chromium, molybdenum, tungsten, manganese, rhenium, zinc, cadmium, lead, aluminum , tin, phosphorus, arsenic, antimony, bismuth, silicon, titanium, zirconium and rare earth metals, and (c) from 0 to 5, preferably from 0.1 to 3 ?, by weight based on (a), from a compound based on an alkali metal or an alkaline earth metal, with the proviso that component (a) is not based on iron or iron and one of the metals selected from the group consisting of coba! or, ruthenium and rhodium, when (b) is a promoter based on a metal selected from the group consisting of t tanium, manganese, chromium and molybdenum and also with the proviso that, when a compound based only on ruthenium or rhodium or ruthenium and rhodium or nickel or rhodium is selected as component (a), the promoter (b) may, if desired, be omitted. Preferred catalysts are those in which component (a) contains at least one compound based <; -v a metal which is selected from the group consisting of nickel, cobalt and iron, in an amount from JO to 95 ?, by weight, ruthenium and / or rhodium in an amount of 0.1 to L > by weight based on each case in the sum of components (a) to (c), component (b) contains at least one promoter based on a metal that is selected from the group consisting of silver, copper, manganese , rhenium, lead, and phosphorus, in an amount from 0.1 to 5% by weight based on (a), and component (b) contains at least one compound based on the alkali metals and alkaline earth metals selected from the group It consists of lithium, sodium, potassium, cesium, magnesium, and calcium, in an amount from 0.1 to 5% by weight. The catalysts which are particularly preferred are: catalyst A, which contains 90% by weight of cobalt oxide (CoO) 5% by weight of manganese oxide (Mn? 05), by weight of phosphorus pentoxide and 2% by weight of sodium oxide (Na, o), 15 catalyst B has 20% by weight of cobalt oxide or (CoO), 5% by weight of manganese oxide (Mn, O, 3% by weight of silver oxide (Ag o), 70% by weight of silica (SiO >), 3 .'- 'by weight of alumina (Al, Oj), 0.4% by weight of iron oxide (b'eO, 0.4 by weight of magnesium (M? O) and , L 0.4% by weight of calcium oxide (CaO), and catalyst C has 20% by weight of nio- (NiO) oxide, 67.42% by weight of silica (Si?), 3.7% by weight « alumina (Al, 0 0.8% by weight of iron oxide (FeO.)?.? by weight of magnesium oxide (MgO), 1.92% by weight of ov '! • > of calcium (CaO), 3.4% by weight of sodium oxide (Na70) and 2.0 by weight of potassium oxide (K? 0). The catalysts which can be used according to the invention can be supported or unsupported catalysts. Examples of suitable carriers are porous oxides, such as alumina, silica, aluminosilicates, lanthanum oxide, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide and zeolites, as well as active carbon or mixtures thereof. As a general rule, the preparation is carried out by precipitating the precursors of the component (a) together with the precursors of the component promoters (b)) and, if desired, with precursors of the trace components (c) in the presence of the carriers (depending on the type of catalyst desired), if desired proceed with the resulting catalyst precursor to give the extrudates or granules, the drying of the latter and then their calcination. Supported catalysts are also obtained in general by impregnating the carrier with a sojui > on of the components (a), (b) and if desired (c), where individual components can be added simultaneously or in succession, by sprinkling the components1 t .. (a), (b), and, if desired, (c), on the carrier mediant «- t •• method known per se. Suitable precursors of the components (a) are, as a rule, easily soluble salts in water of the aforementioned metals, such as nitrates, chlorides, acetates, formations and sulfates, preferably nitrates. Suitable precursors of the components (b) are, as a general rule, readily soluble salts in water or complex salts of the aforementioned metals, such as nitrates, chlorides, acetates, formates and sulphates and in particular hexacy oroplatinate, preferably nitrates and hexachloroplatinate. The suitable precursors of the components (c) are, as a general rule, readily soluble salts in water of alkaline metals and of the aforementioned alkaline earth metals, such as hydroxides, carbonates, nitrates, chlorides, acetates, formates and sulphates. , preferably hydroxides and carbonates. The precipitation is carried out, in general, to part > of aqueous solutions, either by adding precipitating reagents or changing the pH or temperature. The preliminary catalyst material thus obtained by?.? ? . In general, it is dried from 80 to 150 ° C, preferably from 80 to 120 ° C. The calcination is usually carried out at 150 to 500 ° C, and in specific cases it is also possible to obtain temperatures above 1000 ° C, preferably from 200 to 25 450 ° C in a gas stream that contains air or nitrogen, After calcination, the catalyst material obtained is generally exposed to a reducing atmosphere (activation), for example to an atmosphere of hydrogen or a mixture of gases containing hydrogen and an inert gas, such as nitrogen, for 2 to 24 hours and 80 to 250 ° C, preferably 80 to 180 ° C, in the case of catalysts based on ruthenium or rhodium as component (a) or 200 to 500 ° C, preferably 80 to 180 ° C, in the case of catalysts based on ruthenium or rhodium as component (a) or from 200 to 500 ° C, preferably 250 to 400 ° C in the case of catalysts based on a metal that is selected from the group consisting of nickel, cobalt or iron as component (a). The catalyst space velocity in the present preferably is 200 1 per 1 catalyst. Activation of the catalyst is advantageously carried out directly in the synthesis reactor, since this prevents an otherwise necessary intermediate step, or -, say the neutralization of the surface a, so qpn rai, 200 to 80 ° C, preferably from 25 to 35 ° C, by means of a mixture of oxygen / nitrogen, as air. Activation < The catalysts which are then neutralized are preferably carried out in the synthesis reactor at 180 to 500 ° C, preferably at 200 to 350 ° C in a hydrogen-containing atmosphere.

The catalysts can be used as catalytic is fixed bed by the liquid phase or percolator bed process or as a catalyst is in suspension. In a preferred embodiment iron catalysts are used whose surfaces are stabilized by the addition of oxides such as alumina. In general, these additives are prepared by fusing magnetite with the oxide additives, preferably with a method similar to that described in AB Stiles, catalyst Manufacture (1995), pages 167-168 10 (also see BE Leach, Applied Industrial Catalysts, 3 (1984), 123, wherein the ammonia synthesis catalysts are further described.The preferred additives are alumina, potassium oxide and calcium oxide.The particularly preferred catalysts have a BET surface area greater than 5, very particularly 5 to 20, in particular 15 to 20 mVg (the iron catalysts that have been prepared by reducing the freshly prepared material and containing an alumina promoter) are preferred (see MV Twigg, Catalyst Handbook, 2nd edition (1989), Erome, 2C Enqland, page 397.) In another preferred embodiment, the iron catalysts are reduced with hydrogen at temperatures no greater than <b-500 ° C and generally have a content of Arbono no greater than 0.4% by weight.

The initial materials which are used in the novel process are a,? - aliphatic dinitriles of the general formula 1 NC- (CII7) n-CN I where n is an integer from 1 to 10, in particular 2, 3, 4, '6. Particularly preferred compounds 1 are succinonitrile or, glutaronitrile, adiponitrile, pimelonite, and suberonitrile, very particularly preferably adiponitrile. In the novel process, the dinitriles 1 described in the above are partially hydrogenated in the presence of a solvent using a catalyst to give the a, a > -aminonitriles of the general formula 11 NC- (CH7) n-CH? -NH? U where n has the aforementioned meaning. The aminonitri particularly preferred 11 are those in which n is?, 3, 4, 5 or 6, in particular 4, that is, 1 aminobut ironitrile, 5-aminopentanonitri or, 6-aminohexanonitrilo (6-aminocaproni trilo) , 7-aminoheptanon i tp lo and 8-aminoort anonitr. it, very particularly preferred 6-ami nocapron i t ilo. If the reaction is carried out in a suspension, temperatures of from 40 to 1 ° C are preferably chosen, preferably from 50 to 100 ° C, particularly preferably from 60 to 9 d '"<; the pressure is generally chosen in the range of 2 to 20, of. preferably from 3 to 10, particularly preferably from 4 to 8 MPa. The residence times mainly depend on the desired yield and selectivity and the desired conversion; the residence time is usually chosen so that a maximum yield is obtained, for example, in the range of 50 minutes to 275, preferably 70 to 200 minutes when adiponitrile is used. In a suspension process, the solvents that are preferably used are ammonia, amines, diamines and triamines of 1 to 6 carbon atoms, such as trimethylamine, Triethylamine, tripropylamine and tributyl amine or alcohols, preferably methanol and ethanol, particularly preferably ammonia. Advantageously, a dinitrile concentration of 10 to 90, preferably 30 to 80, particularly preferably 40 to 70% by weight based on in the sum of the dinitrile and the solvent. The amount of the catalyst is generally chosen so that the amount of catalyst is from 1 to 50, preferably from 5 to 20% by weight based on the amount of dinitrile used. 2C Hydrogenation in suspension can be carried out,? way of lot or, preferably, continuously, blunt rule generates, 1 in liquid phase. The partial hydrogenation can also be carried out in lime as a batch or continuously in a reactor. fixed by the percolator bed or phase procedure . { 1] liquid, generally a temperature of 20 to 150 ° C, preferably of 30 to 90 ° C and a pressure, as a general rule, is chosen from 2 to 30, preferably from 3 to 20 MPa. According to the present invention, the partial hydrogenation is carried out in the presence of a solvent, preferably ammonia, an amine, a diamine, or a tp amine of 1 to 6 carbon atoms, such as trimethylamine, tri-ethylamine, tripropylamine or tributylamine, or an alcohol, preferably methanol or ethanol, particularly preferably ammonia. In a preferred embodiment, an ammonia content of 1 to 10, preferably 2 to 6 g per g of adiponitrile is chosen. Preferably, a catalyst space velocity of 0.1 to 2.0, preferably 0.3 to 1 kg of adiponitrile per 1 per hour is chosen. The conversion and therefore the selectivity can be controlled by changing the stay time in this case as well. In the novel process, a,? - aminoni trilos are obtained with good selectivity, and only with small amounts of hexamethylenediamine. In addition, the catalysts, which are used, according to the invention, have a substantially longer life than those catalysed. of the prior art comparable. The a, (o-aminonitriles are important initial compounds for the preparation of cyclic lactams, in particular 6-aminocapronitrile to obtain caprolactam.

Examples Comparative Example 1: (Example 2 in DE-A 848, 654) A tube reactor having a length of 4.5 m and an internal diameter of 0.6 cm was filled with 105 ml (96 g) of catalyst consisting of 2.3% by weight of PdO on Sio. < (residue), and the catalyst was then activated at 1 atmospheric pressure for 48 hours in a stream of hydrogen 0 (200 1 / h) by increasing the temperature from 30 to 250 ° C. After the temperature had been incrusted at 120 ° C, a mixture of 55 ml / h of adiponitrile (DNA) 130 ml / h of ammonia and 200 1 / h of hydrogen was fed to the reactor at 180 bar. Under these conditions 13% of 5 adiponitrile was converted. The reaction mixture consisted mainly of 87% by weight of DNA and 3.3% by weight of? CN (6-aminocapronitrile). Under these conditions, the catalyst1 lost 3% of its initial activity per hour of operation.

C Comparative Example 2: (Example 4 in DE-? 848, 654) Using 4% by weight of CuO, 4% by weight of ZnO and 16.6% by weight of Co? 03 or 3iO. > (residue) With the catalyst, a mixture of 55 ml / h of adiponitrile, 10 ml of ammonia and 200 l / h of hydrogen was reacted for a conversion of 50% at 80 ° C and 180 bar in the same reactor as in Comparative Example 1. The reaction mixture consisted of 50% by weight of DNA, 40% by weight of ACN and 9% by weight of HMD (hexamethylenediamine). By increasing the reaction temperature to 95 ° C, the conversion was increased to 69%. The reaction mixture consisted mainly of 31% by weight of DNA, 46% by weight of ACN and 21% by weight of HMD. Under these conditions, the catalyst lost 1% of its initial activity per hours of operation and the molded parts had completely disintegrated after 60 hours.

Comparative Example 3: (Example 3 in DE-A 848, 654) Using 7.5% by weight of CoO and 16% by weight of Fe?, In SiO? (residue) As a catalyst, a mixture of 55 ml / h of adiponitrile, 130 ml / h of ammonia and 200 J / h of hydrogen was reacted for a conversion of 45% at 70 ° C and 180 bar in the same reactor as in Comparative Example 1. The mixture that reacted consisted p by 55% by weight of DNA, 37% by weight of ACN, and 7% by weight of HMD. l Increase the reaction temperature of 85 ° C, the conversion was increased to 78%. The reaction mixture consisted mainly of 22% by weight of DNA, 48% by weight of ACN and 27% by weight of HMD. The catalyst lost 0.5% of its initial productivity per hour of operation and 10% of its initial activity during the 24 hours.

Example 1 A tube reactor having a length of 2 m and an internal diameter of 2.5 cm was filled with 750 ml (1534 g) of 5 catalyst consisting of 90% by weight of CoO, 5% by weight of MripOj, 3% by weight of P7O5, and 2% by weight of Na? ü, and then the catalyst was activated at atmospheric pressure for 48 hours in a stream of hydrogen (500 1 / h) by increasing the temperature from 30 to 280 ° C. After the temperature had been increased to 60 ° C a mixture of 400 ml / h of adiponitrile, 930 ml / h of ammonia and 500 1 / h of hydrogen was fed into the reactor at 200 bar. Under these conditions, 46% adiponitrile was converted. The reaction mixture consisted mainly of 54% by weight of DNA, 15 37% by weight of ACN and 9% by weight of HMD. By increasing the reaction temperature to 70 ° C, the conversion was increased to 65%. The reaction mixture consisted mainly of 34.5% by weight of DNA, 46% by weight of C and 19.5% by weight of HMD. After 900 hours the catalyst still had the same selectivity as the new catalyst, the activity remained unchanged. The molded parts of the catalyst were still intact after the elimination (after 900 hours).

Example 2: A reactor tube having a length of 4.5 m and an internal diameter of 0.6 cm was filled with 105 ml (96 g) of catalyst consisting of 20% by weight of CoO, 5% by weight of Mn2 t, 0.3 % by weight of Ag? 0, 70% by weight of SiO?, 3.5% by weight of Al ^ 0, 0.4% by weight of E'e ^ 0, 0.4% by weight of MgO and 0.4% by weight of CaO, and then the catalyst is activated at atmospheric pressure for 48 hours in a hydrogen current (200 1 / h) increasing the temperature from 30 ° C to 250 ° C. After the temperature had been increased to 90 ° C, a mixture of 55 ml / h of adiponitrile, 130 ml / h of ammonia and 20 1 / h of hydrogen was fed into the reactor at 180 bar. Under these conditions there was a 30% conversion of adiponitrile. The reaction mixture consisted mainly of 65% by weight of DNA, 30% by weight of ACN and 4% by weight of HMD. By increasing the reaction temperature to 100 ° C, the conversion was increased to 71%. The reaction mixture consisted mainly of 29% by weight of? DN, 53% by weight of ACN and 18% by weight HMD. After 300 hours the catalyst still had the same selectivity as the new catalyst, the activity remained unchanged.

Example 3 A tube reactor having a length of 4.5 and s < Internal diameter of 0.6 cm was filled with 105 ml (96 g) catalyst which consists of 20.0% by weight of Nio, 67.4%, by weight of SiO ?, 3.7% by weight of Al70t, 0.8% by weight of Fe; .03, 0.76% by weight of Mn203, 0.92% by weight of CaO, 3.4% by weight of Na ^ O, and 2.0% by weight of K ^ O, and the catalyst was then activated at atmospheric pressure for 48 hours in a hydrogen current (200 1 / h) increasing the temperature from 30 to 250 ° C. After the temperature had been increased to 110 ° C, a mixture of 50 ml / h of adiponitrile, 130 ml / h of ammonia and 200 1 / h of hydrogen was fed into the reactor at 180 bar. Under these conditions, 25% adiponitrile was converted. The reaction mixture consisted mainly of 75% by weight of DNA, 24% by weight of ACN and 0.5% by weight of HMD. By increasing the reaction temperature to 120 ° C, the conversion was increased to 60%. The reaction mixture consisted mainly of 40% by weight of DNA, 53% by weight of 5% ACN by weight of HMD. The catalyst has a constant activity for 100 hours.

Example 4 Long term experiment for 3000 h with catalyst as in Example 1.

A reactor tube having a length of 2 m and an internal diameter of 2.5 cm was filled with 750 ml (1534 g) of catalyst consisting of 90% by weight of CoO 0.5% by weight of Mn? 03.3% by weight of? 0 ^, and 2% by weight of Na? 0, and the catalyst was then activated at atmospheric pressure for 48 hours in a stream of hydrogen (500 1 / h) by increasing the temperature from 30 ° C to 200 ° C. After the temperature had increased to 55 ° C (inlet), or 70 ° C (outlet), a mixture of 400 ml / h of adiponitrile, 1900 ml / h of ammonia and 500 1 / h of hydrogen was fed to the reactor at 200 bar. Under these conditions, 50% adiponitrile was converted. The reaction mixture consisted mainly of 50% by weight of DNA, 39% by weight of? CN and 11% by weight of HMD (selectivity of ACN: 75%, selectivity of ACN + HMD: 100%). After 3000 hours the catalyst still had the same selectivity as the new catalyst, and the activity remained unchanged.

Example 5 catalyst preparation An iron catalyst was obtained by the method < \ < described in Catalyst Manufacture,? .B. Sl.iles and T.A. Koch (1995), pages 167-168, by the fusion of iron oxide (magnetite) with the promoters Al () < , K, 0 as K .CO CaO as calcium carbonate, and then crushed and sieved into solidified molten mixture. In the oxide state, the catalyst had the following composition: 1.1% by weight K, 0, 3.0% by weight of A1.03, and 2.3% by weight of CaO, the residue of Fe0 / Fe? 03- (Area of BET surface: 6.5 mVg, after reduction of the catalyst for 10 hours at 45 ° C in a stream of H? (atmospheric pressure) and subsequent neutralization after cooling with an air / nitrogen mixture).

Experimental result Three tube reactors were connected in series (total length 4. m, d = 6 mm) were filled with 115 ml (303 g) of catalyst and then brought to atmospheric pressure in a stream of hydrogen (200 1 / h) . For this purpose, the temperature was increased from 50 to 340 ° C for 24 hours and then maintained at 340 ° C for 72 hours. After the temperature had been increased to 120 ° C, a mixture of 55 ml / h 'of DNA, 260 ml / h of NH, and 200 1 (S.T.P) / h of hydrogen was fed into the reactor at 250 bar.

After a phase of travel of about 200 hours, a DNA conversion of 475 was obtained under these conditions. The reaction mixture consisted mainly of 53% by weight of DNA, 38% by weight of? CN 8% by weight of HMD (selectivity of ACN: 80.9%, selectivity of? CN and I MP: 98%) . This reaction product was obtained during a period of 400 hours.

Example 6 Preparation of the catalyst A solution containing 9.3% by weight of cobalt, 2.7% by weight of copper, 0.9% by weight of manganese and 0.5% by weight of H, P04 was obtained by dissolving cobalt nitrate, copper nitrate, manganese nitrate and phosphoric acid in water. The precipitation was carried out at 50 ° C with the addition of a 20% strength sodium carbonate solution. The precipitate obtained was washed until the sodium and nitrate were no longer detectable in the wash water. The solid thus obtained was converted into a suspension in water and sprayed in a spray tower (inlet temperatures = 550 ° C). The sprayed material was dried at 500 ° C, ground and extruded to give the 4 mm diameter extrudates. The extrudates were dried at 100 to 120 ° C and calcined for one hour at 900 ° C.

The extrudates thus obtained were reduced in a stream of hydrogen at 320 ° C and neutralized at room temperature with a mixture of n i 1.1 oqeno / air.

Experimental results 270 ml autoclave (batch experiments) starting materials: 36 g of DNA, 54 g (89 ml) of NH < and my catalyst (molded parts) catalyst: 66% CoO, 20% CuO, 7.3% Mn ,? <; 3.6% of Mo03; 0.1% Na 0; 3% H, PO, (53 g).

All the catalysts were reduced with 20 1 / h for 10 hours at 200 ° C before beginning the experiment.

Results of example 6 Temp. / pressure [° CJ [bar] Results of example 6 Temp / pres yield time yield selectivi conversion of the experiment ACN to HMD n of [%] [° C] [bar] such [h] [%] [%] ACN [%] 507200 5 40 13/6 53 50 6 44 17 I? 61

Claims (7)

REINVINDICATIONS

1. A process for the preparation of aliphatic α, α-triamls by the partial hydrogenation of α, α-aliphatic dinitriles at elevated temperatures and superatmospheric pressure in the presence of a solvent and a catcher, the process comprises the use of a catalyst which (a) contains a compound based on a metal that is selected from the group consisting of nickel, cobalt, iron, ruthenium and rhodium, and (b) contains 0.01 to 25% by weight, based on (a) ), of a promoter based on a metal that is selected from the group consisting of palladium, platinum, iridium, osmium, 5 copper, silver, gold, chromium, mol ibdene, tungsten, manganese, rhenium, zinc, cadmium, lead, aluminum , tin, phosphorus, arsenic, antimony, bismuth, sil? < - titanium, zirconium and rare earth metals, and (c) from 0 to 5% by weight based on (a), of a :() compound based on an alkaline metal or an alkaline earth metal, with the proviso that that component (a) is not based on iron or iron and one of the metals that are selected from. group consists of cobalt, ruthenium and rhodium when (b) is a promoter based on a metal that is selected from the group consisting of titanium, manganese, chromium and molybdenum, and also with the proviso that, when a compound based only on ruthenium or rhodium or ruthenium and rhodium or 5 nickel and rhodium is selected as component (a), the promoter (b) can, if desired, be omitted.

2. The process, according to claim 1, wherein the catalyst is a supported catalyst.

3. The process, according to claim 1, in which the catalyst is a catalyst without support.

4. The process, according to any of the claims 1 to 3, wherein the hydrogenation is carried out in a suspension.

5. The process, according to any of the 15 claims 1 to 3, wherein the hydrogenation is carried out in a bed reactor.

6. The process, according to any of the claims 1 to 5, wherein the, -dini tr or used is adiponitrile, to obtain 6- 2U aminocaproni trilo.

7. The process, in accordance with claim 6, r •• where the hydrogenation is carried out from 2 to 40 MP. process, with orm with a re nv n c 7, where the hydrogenation is carried out from 30 to 150 ° C. SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of aliphatic α, β-aminonitriles by the partial hydrogenation of aliphatic α, α-dinitriles at elevated temperatures and atmospheric pressure in the presence of a solvent and a catalyst, the process comprises the use of a catalyst which (a) contains a compound based on a metal that is selected from the group consisting of nickel, cobalt, iron, ruthenium and rhodium, and (b) contains from 0.01 to 25% by weight, based on (a), of a promoter based on a metal that is selected from the group consisting of palladium, platinum, iridium, osmium, ro, or > silver, gold, chromium, molybdenum, tungsten, manganese, rhenium, zinc, cadmium, lead, aluminum, tin, fosfo-e, arsenic, antimony, bismuth, silicon titanium, cirro-i., and rare earth metals, and (c) from 0 to 5% by weight based on (a), of a compound based on an alkali metal or an alkaline earth metal, with the proviso that component (a) is not based on iron or iron and The metals that are selected from the group consist of cobalt, ruthenium and rhodium, when (b) is a promoter based on a metal that is selected from the group consisting of titanium, manganese, chromium and molybdenum, and also provided that , when a compound based only on ruthenium or rhodium or ruthenium and rhodium or nickel and rhodium is selected as component (a), the promoter (b) may, if desired, be omitted.