WO2004060833A2

WO2004060833A2 - Process for synthesizing amine from nitrile

Info

Publication number: WO2004060833A2
Application number: PCT/US2003/041536
Authority: WO
Inventors: Philippe Marion; David Michael Lowe; Anthony F. Volpe, Jr.; Thomas Weskamp
Original assignee: Rhodia Chimie
Priority date: 2002-12-31
Filing date: 2003-12-31
Publication date: 2004-07-22
Also published as: WO2004060833A3; AU2003303563A8; AU2003303563A1

Abstract

The present invention relates to a process for synthesizing amine from nitrile. This hydrogenation process is carried out in a condensed. Advantageously liquid phase on a substrate carrying a nitrile function and an imine function. Wherein a Raney(r) type cobalt doped with potentiator elements is used as a catalyst. Said doped catalyst advantageously including as potentiator element(s) at least either nickel or chrome or preferably both nickel and chrome. This method is applicable to organic synthesis.

Description

_PROCESS FOR SYNTHESIZING AMINE FROM NITRILE

The present invention relates to a process for hydrogenating an imine function and a nitrile function. _In particular, it relates to the simultaneous hydrogenation (the latter term has the meaning of "performed in the same reaction medium") , of at least one imine function and at least one nitrile function carried by the same substrate. In the industry, there is often a need for aliphatic diamines, including cycloaliphatic diamines. These diamines, which are most often primary ones, are more specifically used for making polycondensates such as polyurea or polyamide or as an intermediate in the formation of isocyanates, whether masked or no-:.

The most commonly used syntheses include a step for hydrogenating one or more nitrile functions. The reduction of the nitrile function involves an imine intermediate. However, in general, this function is more reducible than the nitrile function, the first hydrogenation being the factor, which limits kinetics, so that the intermediate imine amount is relatively small in the reaction media.

The coexistence within the reaction medium of a primary arr.ine function with an imine leads to the formation of an N-substituted imine which, after reduction, forms a secondary amine making up, in many cases, an impurity both undesirable and expensive to eliminate. This problem becomes even more acute when the geometry of the substrate molecule lends itself to the formation of an internal secondary imine, for example when an amine function of the substrate being hydrogenated may react intramolecularly on an imine function, a nitrile function, or even another amine function, and thus will form a five-, six- and/or five- membered ring. Thus, when the amines and/or the nitrile (s) are carried by a ring, a transition can be made from a monocyclic substrate to a pαlycyclic secondary amine.

This transimination problem is even more acute if the imine function is not an intermediate function occurring within the reaction medium but exists within the initial substrate which then includes, before any other processing, an imine function.

Moreover, when it is attempted to carry out the reaction in a single step by reducing the imine produced in situ by a ketone amine condensation, alcohol corresponding to ketone reduction will often form. In order to remedy these difficulties as far as possible, it is appropriate to make the imine functions as little concentrated as possible. For that purpose, in the case of the initial imine functions, a two-step hydrogenation technique is used in the art, wherein the first one reduces the initial keti ine into amine and the second one reduces nitrile into amine. This solution is both costly and poses geometric isomery problems, which will be addressed thereafter.

Another solution would be to use a catalyst for promoting the transition reaction from nitrile to amine: in particular, the catalyst system should allow appropriate hydrogenation kinetics of the nitrile function without degrading the hydrogenation kinetics of the ketimine function. The difficulty to overcome is that most often these properties are, to a large extent, conflicting or deemed to be so.

Also, in the case of geometric isomery, and in particular, of cis/trans isomery, the reaction velocity and temperature play an important part. Specifically, as the temperature and. the reduction duration increase, thermodynamic ratios tend to deviate from the most favorable ones or the required ones. Finally, imine hydrogenation catalysts very often also behave as cis/trans isomerization catalysts.

The latter aspect is particularly acute for cis/trans iso eries in cycloaliphatic amines.

Thus, whe the imine function is on an intracyclic carbon atom, the hydrogenation leads to a cis/trans isomery with respect to the nitrile function. The ratio between the cis and trans forms is governed, on the one hand, by kinetics factors and on the other hand, by a thermodynamic characteristic related to the nitrile function. During hydrogenation, the system's nitrile function tends to approach the thermodynamic ratio, which does not correspond to the equilibrium of the intermediate amine, or former i ine/nitrile system, but corresponds to the equilibrium of the final polyamine system where nitrile is transformed into an aminomethyl function (NH₂-CH₂~) .

The synthesis of a compound commonly referred to by the abbreviation IPDA (IsoPhoroneDiAmine) is an appropriate example of the type of problems that are faced and may serve as a paradigm (an example for teaching a rule) .

Isophorone is a molecule resulting from the three- step condensation of acetone, which after adding a hydrocyanic acid molecule after condensation with ammonia and hydrogenation gives IPDA. The industry desires and uses an IPDA having a cis/trans ratio of about 3. Since it is easier to decrease than to increase it, it is appropriate to aim at ratios that are greater or equal to this value. Given below are the cis- and trans- formulae of

IPDA, as well as the ratio usually desired . The cis- and trans- forms are chiral but the racemic forms are conventionally used .

Cis (e/e) / 75% Trans (a/e) .25% It is therefore an object of the present invention to provide a process for obtaining, in a single step (that is, in a single reaction medium and with the same catalyst) , a diamine or a polyamine by hydrogenating a substrate or an intermediate compound comprising at least one nitrile function and at least one imine function, even transiently.

Another object of the present invention is to provide a process of the above-mentioned kind for obtaining an IPDA yield (RR relative to isophorone nitrile) of at least 80%, advantageously 85%, and preferably 90%.

Another object of the present invention is to provide a process of the above-mentioned type, which allows, when applied to the synthesis of a cycloaliphatic polyamine, a cis/trans isomeric ratio to be obtained, which differs by at least 30%, and advantageously, by at least 100%, from the thermodynamic equilibrium at the reaction temperature.

Another object of the present invention is to provide a catalyst system, which enables accelerated kinetics of the hydrogenation reaction of nitrile func_tions by maintaining fast kinetics for hydrogenating the imine function.

These and other objects of this invention will _become clear in the following and are achieved by means of a hydrogenation process in a condensed, and advantageously liquid phase, of a substrate carrying a nitrile function and an imine function, wherein one uses as a catalyst a Raney® type cobalt doped (that is potentiated) with potentiator elements, advantageously at least two potentiator elements, chosen from the following group : gallium, chromium., nickel, platinum group metals (in particular rhodium and iridium) , hafnium, zirconium, lead and tin with the proviso that lead and tin are to be avoided when nickel is one of the other potentiator and characterized in that said doped catalyst includes as potentiator element (s) at least either nickel or chromium or preferably both nickel and chromium.

The catalyst further contains aluminum, which originates from the mother alloy precursor to the catalyst (it should be recalled that Raney® type catalysts are obtained through alkaline leaching of aluminum alloys, of the catalyst base metal and possibly, of all or part of the potentiator metals described below) ; it is also preferable, in particular for those whose action is related to a metal form (zero oxidation level) , that the potentiator metals having a redox potential, under the. processing conditions of the invention, close to (that is in the inclusive range of +0.3V) or greater than that of aluminum, be introduced in the initial aluminum alloy) . Aluminum is not considered as a potentiator agent in the present invention. _In general, the atomic ratio of aluminum to the base metal in the catalysts is 1/3, and advantageously at most 1/4, and preferably at most 1/10.

_Iron is often present as impurity in the mother alloy. It has no detrimental effect on the property of the catalyst; on the contrary, when used according to present invention, it enhances the property of the catalyst at least when the content expressed in atomic percentage towards cobalt is at most equal to 5% advantageously 2.5%. The effect is also measurable when iron is used in the liquid phase.

Thus, the catalyst is potentiated by at least two elements that are different from the base metal comprising the catalyst. These elements behave or serve as co-catalysts and are chosen from the following group: gallium, chromium, nickel, plati um group metals (in particular rhodium and iridium) , hafnium, zirconium, lead and tin with the proviso that lead and tin are to be avoided when nickel is cne of the other potentiator. Thus, the catalysts according to the present invention include cobalt-based those:

^• containing at least chromium as a potentiator element;

^• containing at least nickel as a potentiator element; the nickel being advantageously present initially in the mother alloy; It is preferably in the form of an solid solution in the metal or in the form of inter-metallic compounds with cobalt, aluminium and/or iron; ^• and advantageously, containing at least both nickel and chromium as the potentiator elements .

It is desirable that the atomic ratio [co- cat] /[cat] cf each of the elements present as the co- catalyst to the base metal (i.e. cobalt) in the catalyst be at least 1/1000, advantageously at least 5/1000, and preferably, at least 1%.

It is also desirable that the [co-cat] / [cat] atomic ratio of each of the elements present as the co-catalyst (in particular nickel and chromium) to the base metal in the catalyst be at most 1/10, and preferably, at most

1/20.

Desirably, the [∑co-cat] / [cat] atomic ratio of the sum of the elements present as the co-catalyst (s) to the metal in the catalyst will be at least 2/1000, advantageously at least 5/1000, preferably at least 1%, and more preferably, 2%.

It is also desirable that the [∑co-cat] / [cat] atomic ratio of the sum of the elements present as the co-catalyst (s) to the metal in the catalyst be at most

1/3, advantageously at most 1/5, preferably at most 1/10 and more preferably at most 7%.

Thus, according to the present invention, it is suggested to use at least two elements other than cobalt acting as potentiator element, in other words acting as co-catalysts to cobalt.

The co-catalyst elements may be introduced into the mother aluminum alloy comprising the raw material of the Raney® type metal, before the alkaline leaching. This is the best way to introduce nickel.

They may also be introduced as salts, which should advantageously be soluble, into the initial reaction medium but also as salts during the alkaline leaching of the alloy. It should be stressed that introducing by this way the nickel is not advisable since at best nickel as low effect and at worst it could provide a pure nickel layer that is a bad catalyst thus implying the decrease of the catalytic power. The use of such catalysts, although it is not restricted to the present implerr.entation, allows the reduction of the imine function and the nitrile function to be performed in the same reaction medium, that is, without any intermediate isolation and purification.

According to the present invention, it is advised to add further potentiator metal (s) to the cobalt catalyst doped by nickel and/or chromium. This further potentiato (s) are advantageously chosen among the platinum group metals and zirconium and even hafnium. Thus, good catalyst according to the present invention could be chosen among the following ones:

- Raney® type cobalt doped with chromium and potentiated by at least one of the element chosen among platinum group metals, zirconium and possibly hafnium.

- Raney® type cobalt doped with nickel and potentiated by at least one of the elemenc chosen among chromium, platinum group metals, zirconium and possibly hafnium.

- Raney® type cobalt doped with chromium and nickel and further potentiated by at least one of the element chosen among platinum group metals, zirconium and possibly hafnium.

The presence of water in the reaction medium is rather favorable, and in particular enables processing of ketones that are iminated in situ due to the action of ammonia without needing to eliminate the water formed during imination. Adding water has some advantages.

The effect cf water is sensitive for substrate/catalyst ratios at least equal to 0.02 mole per gram of catalyst, advantageously from 0.03 to 0.3, preferably from 0.05 to 0.2.

The preferred processing conditions are as follows:

- Temperature: from 40^DC to 150°C and advantageously from o0^oC to 120°C (temperature is not required to be kept permanently at a single value chosen within this range and it may advantageously be programmed so as to increase while the reaction proceeds either continuously or stepwise) ; - Total pressure: from 10^s to 10⁷ Pa, advantageously, from 2.10⁶ to 8.10⁶Pa and preferably from 2.10* to 6.10⁶ Pa;

- P_H2: from 5.10^s to 9.10^s Pa, and preferably from 3.10^s to 5.10^s Pa; - Ammonia/imine mole ratio: at least two, and the upper limit is economic rather than technical but an upper limit for this ratio would be 100.

- Catalyst/substrate weight ratio: at least 0.5%, and the upper limit is economic rather than technical, but an upper limit for this ratio would be of at most 50%.

The reaction is performed in a liquid phase, advantageously in a solvent or a solvent system, the solvents being chosen from common solvents for nitrile hydrogenation.

In particular, these common solvents include alcohols, preferably primary ones, including in particular ethanol, ethers, particularly cyclic ethers

(such as dioxane, THF and tetrahydropyrane) and mixtures thereof.

The presence of water is very important. In this regard, it is desirable that the [H₂0] / [substrate] ratio of water, expressed in moles, to the imine function, expressed as an equivalent, be at least 1, advantageously 2, and preferably 3.

However, this presence should be moderate. Thus, it is desirable that the [H_:0] / [imine] ratio of water, expressed in moles, to the imine function, expressed as - an equivalent, be at most 10, and advantageously 3. It is desirable that for said hydrogenation step, the ratio of ammonia, expressed in moles, to the imine functions, expressed as an equivalent

( [NH₃] /[substrate] ) , be at least 2, advantageously 4, and preferably 6.

In order to obtain a good yield, it is preferable that the ratio ( [NH_a] / [imine] ) of ammonia, expressed in moles, to the imine functions, expressed as an equivalent, be at most 50, and advantageously 25. It is advisable to choose as the ratio of ammonia, expressed in moles, to water, expressed in moles ( NHa] / [H„0] ) , a value of at least 1, advantageously 2, and preferably 5-

Said process is particularly well suited to substrates which have at least one nitrile function carried by an aliphatic ring, especially when said substrate initially has an imine function carried by an aliphatic ring.

The method is particularly useful when said substrate is such that the final diamine has a cis/trans isomery with respect to a ring carrying the amine and a inomethyl functions (-CH₂-NH₂) .

In this case, it is preferable that said hydrogenation step be stopped before the ratio corresponding to the cis/trans therir.odynamic equilibrium is reached.

Advantageously, in the substrate, the imine and nitrile functions of the substrate are carried by an aliphatic isocyclic radical, wherein the nitrile function is carried by an intracyclic sp³ hybridization carbon atom and the imine function carrying carbon atom is intracyclic and is linked to sp³ hybridization carbon atoms . The obtained results are of particular interest when _the process is used for synthesizing cycloaliphatic amines, which are usually employed as the raw material for cycloaliphatic isocyanate ( BDI, Hι₂MDI) and especially, for synthesizing IPDA.

The process according to the present invention leads to cis/trans ratios greater than 3 (which may range up to 5 or even about 15) . When needed, a simple heating step allows this ratio to be reduced to the desired value (in general, about 3, as mentioned above) .

The reaction time generally ranges from 1 hour to

10 hours, and advantageously, from 3 to 3 hours. It is good practice to interrupt the reaction when the conversion rate of the nitrile function and the intermediate amidinε reaches a predetermined value ranging from 90% to 99%, and advantageously from 95% to 98%. The catalyst amount and hydrogen partial pressure are then chosen for the conversion rate to reach the chosen value after a time duration ranging from 1 hour to 10 hours.

With a high ratio of the catalyst to the substrate the isomeric ratio approaches the kinetic ratio and conversely, a small ratio will drive it closer to the thermodynamic ratio (albeit with difficulties in the conversion of the intermediate compounds) . Thus, in the case of IPDA originating from isophorone nitrile, the cis/trans ratio increases with the catalyst/substrate ratio.

It should be recalled that iminated isophorone nitrile has the following formula:

and is sometimes introduced as a mixture with the following equilibrium:

In particular, in the presence of water, one of the advantages of the present invention is to be able to dispense with the presence of a hydroxide (or any compound leading thereto in the reaction medium) , notably a monovalent metal or a quaternary ammonium. On the contrary, these hydroxides are objectionable according to the present invention.

Thus, according to the present invention, the content of these compounds is more related to the impurity of the components of the reaction medium than to a possible intentional addition. It should therefore be mentioned that, preferably, the reaction mixture should contain at most 1%, advantageously at most l%o and preferably 100 pprr. in weight of such hydroxides, in particular alkaline metals. The definitions of the various yield concepts will be summarized below: TT = Transformation rate of the starting material

WITH number of moles of converted material

TT= ' number of moles of initial material

RR = yield over the initial material WITH

P number of moles of end material number of moles of initial material RT = yield of converted material WITH number of moles of final material

RR= number of moles of converted material

CATAI-YSTS TESTED IN EXA-PLES:

Grace Davison 2700 Catalyst:

97.51%) Cobalt (94.0% minimum, 100% maximum

1,85% Aluminum (5.0% maximum)

0.3% Iron (0.5% maximum) 0.34% Nickel (0.5% maximum) pH 9.2 (10.0 maximum)

13 ppm (50 maximum) of Sodium Oxide

0.1 ppm (10 maximum) of Aluminum Oxide

Particle Size <10^Εh%: 7.33 microns (5.0 minimum) Particle Size <50^ch %: 30.08 microns (20.0 minimum, 40.0 maximum)

Particle Size <90^th %: 81.79 microns (110.0 maximum)

Grace Davison 2724 Catalyst:: 91.7% Cobalt (89.1% minimum, 92.8% maximum)

3.27% Aluminum (3.0% minimum, 5.0% maximum)

0.3% Iron (0.7% maximum)

2.13% Chromium (1.8% minimum, 2.4% maximum)

2.58% Nickel (2.4% minimum, 2.8% maximum) pH 9.5 (8-7 ir.ini um, 10.0 maximum)

12.5 ppm (50 maximum) of Sodium Oxide

0.1 ppm (10 maximum) of Aluminum Oxide

Particle Size <10^th%: 5.98 microns (5.0 minimum) Particle Size <50 %: 26.94 microns (25.0 minimum, 45.0 maximum)

Particle Size <90^rh %: 71.37 microns (110.0 maximum)

Hydrogen Desorption: 11 ml/g (9.3 minimum) 5

--.ctivatad Metals Corporation A-8B46 Catalyst:

90.7% or 86.75% Cobalt (83% minimum) 3.55% or 4.05% Aluminum (8% maximum) 0.33% Iron (0.7% maximum) C Chromium -I- Nickel ~ 5% (analyzed 2.1% Cr and 2.4% Ni) Average Particle Size: 55 or 35 microns pH 11.5 (13 maximum)

EROCEDURE FOR EXPERIMENTS: 5 Preparation of the stock solutions

50 grams each of the catalysts were thoroughly washed inside a glove box with water, then methancl, then diethyl ether, and finally blown dry with a stream of nitrogen. The oxygen level was kept at 0.5 ppm or 0 less .

Stock solutions of the substrates dissolved in various solvents (here methanol if not otherwise mentioned) containing an internal standard, ammonia, and water were prepared and stored at -4C. 5 For these examples, the substrate was isophorone nitrile (IPN) ; the solvent was methanol; the internal standard was triethylene glycol dimethyl ether (triglyme) ; and the ammonia to substrate molar ratio was approximately 20. 0 Isophorone imine nitrile (IPIN) and water were formed in situ and were stable in the stock solution.

Dry catalyst powders were added to arrays of 96 glass vials (1 ml each) in common headspace parallel batch reactors for high-throughput testing (see European 5 Patent Application No. EP 1174185. Stock solu_tions were added into vials (total amount 330 mg ± 5 g) and the reactors were sealed before removing them from the glove box. The reactors were place_d in a vortex-heating unit and a gas line was at_tached that was evacuated and purged several times at 25°C before pressurizing with hydrogen (35 bar except if mentioned otherwise (one bar is 100 kPa) (500 psi) for these examples) . The vortexing speed was increased to 800 rp before the reactors were heated to the reaction temperature. The maximum total pressure varied between 40 bar (590 psi) and 50 bar (740 psi) for these experiments. After a set period of time (^β hours except if mentioned otherwise) , the vortexing was stopped and the reactors cooled to 25°C or less before transferring then- to the glove box. Liquid samples were withdrawn and analyzed by GC/MS and calibrated GC methods . Effect of the potentiator elements

The hereinafter examples show the effects of different catalysts and additives on the IPDA Yield and Cis/Trans Ratio.

Example 1 : effect of the potentiator elements introduced. in the alloy precursor of the; Raney® type cobalt

In these experiments, a 2700 or 2724 Cobalt catalyst from Grace Davison was used; the reaction temperature was 80 °C. The water content corresponds to the water formed by the ammonia ketone condensation. The catalyst to substrate weight ratio was the same for the two experiments. Without additives, the 2724 catalyst gave a higher yield and lower Cis/Trans ratio than the 2700 catalyst, 89.2% and 3.2 versus 35% and 3 .5 $ .

I Catalyst I Content % by weight in I IPDA I Cis/Trans I used Yield Ratio

Further experiments were carried out to compare Grace Davison 2700 catalyst with A8-B46 the reaction temperature was 8G°C

The substrate to catalyst weight ratio (IPNZcat)was 8.2 ± 0.2; and the reaction time was 6 hours. The results is given in the following table:

Example -_ : effect of potentiator elements introduced through liquid phase on Raney® type cobalt with low nickel content

The reaction temperature was 80°C. The water content corresponds to the water formed by the ammonia ketone condensation.

The catalyst to substrate weight ratio was the same in all the experiments and the reaction time was 6 hours .

The amount of additive used (1.3 mole % of the active metal) was calculated by assuming that the catalyst was pure cobalt and that only 10 wt. % was active as a catalyst. Additives dissolved in methanol were added to the catalysts in vials that were agitated then allowed to stand overnight. The samples were then dried by gently blowing off the solvent with a stream of pure nitrogen gas inside a glove box. Acetylacetonates of hafnium, chromium, and iridium as well as tin acetate decreased the Cis/Trans ratio and/or increased the IPDA yield of the 2700 catalyst. Effect of one potentiator element on Raney® type cobalt with low nickel content Operating- parameters :

Catalyst: Grace Co 2700 IPN/Cat, mg/mg: the same for all the tests

Total estimated Maximum Pressure, psi: 652

NH₃/H?N, mole/mole: 20,00

Total Solvent/IPN, mg/mg: 17,87 Solventl: MeOH

Active Metal, moles: 3,6181E-06

Approximate Solventl, mg: 310,0

Solvent2 : None

IPN, mg: 17_f4 Triglyme (Internal Standard), mg: 18,7

--H3, mg: 35 ₈

Tβmperaturel , °C: g Q

Hold Tiiuel , hrs : 6

H₂ Pill Pressure at 25° C, psi: 500 Maximum Gas Pressure, psi: 595 3

Estimated Maximum Vapor Pressure, psi: 57,0

Speed, rpm: 800

Example 3: effect of one potentiator element (additive) on Raney© type cobalt already doped with nickel and chromium

The reaction temperature was 80^aC. The water content corresponds to the water formed by the ammonia ketone condensation.

The catalyst to substrate weight ratio was 0.13; and the reaction time was 6 hours.

The amount of additive used (1.3 mole % of the active metal) was calculated by assuming that the catalyst was pure cobalt and that only 10 wt. % was active as a catalyst. Additives dissolved in methanol were added to the catalysts in vials that were agitated then allowed to stand overnight. The samples were then dried by gently blowing off the solvent with a stream of pure nitrogen gas inside a glove box. Palladium acetylacetonate slightly increased the IPDA yield of the 2724 catalyst..

ft-d-dit--.vθ . Additive Additive Additiv , IPDA <:is/Tra mol % of MW, g/mole Yield, Ratic

Active %

Metal

0 None 0 0 58.0 12.9

6 Nb(OEt) 5 318.22 0.971343S8 52.0 12.1

6 Ni(acac)2 256.93 0.78466422 41.0 11.6

6 2r (acac) 4 487.66 1.48931364 64.0 12.0

6 Re207 484.4 1.4793576 0.0 0.0

6 Ru (acac) 3 398.4 1.2167136 64.0 12.1

6 Ti0(acac)2 262.12 0.80051448 38.0 10.8

6 V(acac) 3 346.27 1.06361658 19.0 7.9

6 2n(OAc)2 183.46 0.56023684 25.0 8 . 6

6 Rh (acac) 3 400.24 1.22233296 63.0 12 . A

When introduced through liquid phase;

- The nickel is a bad potentiator,

- The platinum group metals are good potentiators.

The niobium, rhenium, titanium, vanadium and zinc are comparative.

Example 4 : temperature e ect In both cases the conditions are

- Catalyst used: A-8B46 Cobalt;

- Catalyst to Substrate Weight Ratio: 0.48; the reaction time: 6 hours. Temperatures tested: 60°C and 100°C. The water content corresponds to the water formed by the ammonia ketone condensation.

The experimental parameters are otherwise identical .

For reaction temperature of 60^CC, and for an average of 12 tests, the results read as follows:

IPDA Yield: 87. C% (standard deviation 0.4) and Cis/Trans Ratio 4.3 (standard deviation 0.2) . For reaction temperature of 100^CC, and for an average of 8 tests, the results read as follows:

- IPDA Yield: 89.1% (standard deviation 0.3)

- and Cis/Trans Ratio 4.3 (standard deviation 0-1). The IPDA yield increased and the Cis/Trans Ratio decreased as the Temperature was increased.

Example 5: effect of the Catalyst to Substrate Weight Ratio on the IPDA -field and Cis/Trans ratio

Two groups of experiment were tested.

In both groups of experiments, an A-8B46 Cobalt catalyst from Activated Metals Corporation was used; the reaction temperature was 100^CC; and the reaction time was 6 hours. The catalyst to substrate ratio for the first group of experiments (3 tests) was 0.48, and 0.11 for the second group (six tests) of experiments. The water content corresponds to the water formed by the ammonia ketone condensation. The samples were otherwise identical.

The results read as follows:

At these reaction conditions, the IPDA Yield increased and the Cis/Trans Ratio remained approximately the same as the catalyst to substrate weight ratio was increased.

Example 6: the effect of the Reaction Time

The effect of the Reaction Time on the IPDA Yield and Cis/Trans Ratio is illustrated hereinafter. The average of three Data Set are compared:

❖ 8 Experiments for a duration of 3 hours;

❖ 4 Experiments for a duration of 6 hours;

❖ 10 Experiments for a duration of 12 hours.

The water content corresponds to the water formed by the ammonia ketone condensation.

In all cases, an A-8B46 Cobalt catalyst from Activated Metals Corporation was used; the Catalyst to Substrate Weight Ratio was 0.48; and the reaction temperature was 80°C. The reaction time was changed from 3 to 6- and then 12 hours. They were otherwise identical.

The average values read as follows:

Example 7 : e fect of the alkaline hydroxides

Example 8: effect of water: test in Parr Bomb

The tests were carried under hydrogen partial pressure of 35 bar with a molar ratio NH₃/IPN equal to 20 with a IPN/Cat ratio (by weight) equal to 3,8 p/p. in all of the following test IPN conversion was complete but the intermediate conversion is only partial. Thus the reactions were not finished. These conditions allow having good approach of the effect of the parameters .

Table: _Effect of water content on the efficiency of the catalyst (at time -= 6h)

Operating conditions :

Claims

1. A process for hydrogenating. in a condensed, and advantageously liquid phase, a substrate carrying a nitrile function and an imine function, wherein one uses as a catalyst a Raney® type cobalt doped (i.e. potentiated) with potentiator elements, advantageously at least two potentiator elements, chosen from the following group: from the following group: gallium, chromium, nickel, platinum group metals (in particular rhodium and iridium) , hafnium, zirconium, lead and tin with the proviso that lead and tin are to be avoided when nickel is one of the other potentiator, and characterized in that said doped catalyst includes as potentiator element (s) at least either nickel or chromium or preferably both nickel and chromium.

2. The process of claim 1. characterized in that the atomic ratio of each of the elements present as the co-catalyst to the metal in the catalyst is at least 1/1000 and advantageously at least 5/1000.

3. The process of claims 1 and 2. characterized in that the [∑co-cat] / [cat] atomic ratio of the sum of the elements present as the co-catalyst (s) to the metal in the catalyst is at most 1/3. advantageously at most 1/5. preferably at most 1/10 and more preferably, at most 7%.

4. The process according to claims 1 to 3. characterized in that it includes at least one hydrogenation step in the presence of said catalyst, and m the presence of water and ammonia.

5. The process of claims 1 to 4- characterized in that the [H₂0] / [substrate] ratio of water expressed in moles. to the imine function expressed as an equivalent. is at least 1. advantageously 2. and preferably 3.

6. The process of claims 1 to 5. characterized in that the [H₂0] / [substrate] ratio of water. expressed in moles. to the imine function. expressed as an equivalent, is at most 10.

7. The process of claims 1 to 6. characterized in said hydrogenation step takes place in the presence of ammonia and the ratio of ammonia. expressed in moles, to the imine function (s) in the substrate. expressed as an equivalent ( [NH₂] / [substrate] ) . is at least 1 and advantageously 2.

8. The process of claims 1 to 7. characterized in said hydrogenation step takes place in the presence of ammonia .and the ratio of ammonia, expressed in moles, to the imine function, expressed as an equivalent ( [NH3] / [substrate] ) . is at most 50 and advantageously 25.

9. The process of claims 1 to S. characterized in that said hydrogenation step is carried out in the presence of ammonia and the ratio of ammonia, expressed in moles. to water. expressed in moles ( [NH₃] / [H₂0] ) is at least 1. advantageously 2. and preferably 5.

10. The process of claims 1 to 9- characterized in that said substrate has a nitrile function carried by an aliphatic ring.

11. The process of claims 1 to 10. characterized in that said substrate has an imine function carried by an aliphatic ring.

12. The process of claims 1 to 11- characterized in that said substrate is such that the final diamine has a cis/trans isomery with respect to the ring carrying the amine and aminomethyl (-CH₂-NH₂) functions .

13. The process of claim 12. characterized in that said hydrogenation step is stepped before the cis/trans thermodynamic ratio is reached.

14. The process of claims 1 to 14. characterized in that the imine and nitrile functions of the substrate are carried by an aliphatic isocyclic radical. the nitrile function being carried by an intracyclic sp³ hybridization carbon atom and the atom carbon carrying the imine function being intracyclic and linked to the sp³ hybridization carbon atoms.

15. The process of claims 1 to 14. characterised in that the hydrogenation of the imine and nitrile functions is carried out in the same reaction medium.