ES2337004A1 - Procedure for the selective hydrogenation of nitrocycloalkanes to obtain cyclic oximes - Google Patents

Abstract

The present invention relates to a procedure for the selective hydrogenation of nitrocycloalkanes, substituted or not, comprising carrying out a catalytic hydrogenation of said compounds utilising a catalyst comprising at least one metal, being Pt, supported on titanium oxide, iron oxide, cerium oxide, alumina, carbon, active carbon, magnesium oxide, zirconium oxide, silica, silicic acid, lanthanum oxide, zinc oxide, calcium carbonate, calcium phosphate, calcium sulphate, barium sulphate and combinations thereof. Furthermore said catalyst may comprise a modifier metal selected from one or more alkaline or alkaline earth metals.

Description

Selective hydrogenation process of nitrocycloalkanes to obtain cyclic oximes.

Technical field

The present invention relates to a procedure for the selective hydrogenation of nitrocycloalkanes in the presence or not of other reducible functional groups, using supported metal catalysts that include metals alkaline

Background

In recent years, the use of cyclic oximes as reaction intermediates in the production of polymers, resins, dyes, pesticides, etc., has aroused great industrial interest. The production of Nylon-6 has become an important reference in the industrial production of polymers, and its demand continues to expand today. Epsilon-caprolactam, precursor of Nylon-6, is obtained industrially from cyclohexanone, which is converted into cyclohexanone oxime and finally rearranged to form lactam in a three-stage process. While great effort has been made in Beckmann's rearrangement of cyclohexanone oxime (US5304643, US5264571, DE19608660), it should be borne in mind that aerobic oxidation from cyclohexane to cyclohexanone limits the total efficiency of the process, given the low yields achieved per stage (~ 5%) with homogeneous cobalt catalysts (US3644526, GB1315983). In addition, the need to use hydroxylamine to produce cyclohexanone oxime or H2O2 and ammonia hydroxide for the in situ production of hydroxylamine (US5320819), introduces another sensitive reaction step.

Other alternative processes for production of epsilon-caprolactam have been raised without Too much success

In US4504681 the use of tungsten catalysts to produce cyclohexanone oxime by partial oxidation of cyclohexylamine is claimed. However, low yields to the oxime (<7%) completely limit the application of this procedure during the epsilon-caprolactam production sequence. Recently (SK Klitgaard et al , Green Chemistry 10, 2008, 419) a reaction sequence has been proposed that involves the controlled oxidation of cyclohexylamine to cyclohexanone oxime using TiO2 as a catalyst. Despite the increased yield to oxime by this process (~ 60%), the selectivity obtained and the total duration of the reaction (10 days) clearly limit the interest of the process.

In WO2007116112 the use of Gold catalysts to produce cyclohexanone oxime by hydrogenation of 1-nitro-1-cyclohexene. The selectivity and activity of these catalysts is good, with yields greater than 90%, but it requires as raw material 1-nitro-1-cyclohexene.

Unlike the hydrogenation process of 1-nitro-1-cyclohexene, partial reduction of nitrocyclohexane to cyclohexanone oxime presents background at industrial level. GB860340 describes the hydrogenation of nitrocyclohexane to cyclohexanone oxime using a supported catalyst of Pd working at 35 bar, 413 K, and in presence of a source of Pb. Unfortunately, to reach moderate yields to oxime (~ 70%) this process requires high pressures and the use of PbO salts, environmentally Toxic

On the other hand, to carry out a cyclohexanone oxime production from nitrocyclohexane, se you must previously produce this nitrocycloalkane, and nitration industrial, although economical, only entails a performance per step 16% and under severe reaction conditions (523-673 K). However, in US6468487 the possibility of nitrating cyclohexane under mild reaction conditions (343 K) and with selectivities to 70% nitrocyclohexane, which increases the prospects for an industrial production of Cyclohexanone oxime from this substrate.

In the present invention, it has been found that certain catalysts based on Pt nanoparticles and containing one or more alkali metals are capable of catalyzing selectively hydrogenation of nitro to oxime groups in cyclic nitroalkanes, using H2 or other donor molecule of hydrogen as a reducing agent, when supported on a support adequate and activated properly.

Object of the invention

The present invention relates to a procedure for the selective hydrogenation of nitrocycloalkanes, substituted or not, which comprises carrying out hydrogenation catalytic of said compounds using a catalyst that it comprises at least one metal that is Pt, supported on oxide of titanium, iron oxide, cerium oxide, alumina, carbon, coal active, magnesium oxide, zirconium oxide, silica, acid silicic, lanthanum oxide, zinc oxide, calcium carbonate, calcium phosphate, calcium sulfate, barium sulfate and combinations thereof.

The modified Pt, or Pt as explained more later in this memory, it is supported in order to increase your dispersion and decrease the particle size on supports of inorganic or carbonaceous nature, as it is known in the field of metal catalysts.

Some of these metal oxides can play a role simply as physical supports of the Pt nanoparticles or a mechanistic role in the catalytic process of reducing nitro groups to oximes, so that it is possible to avoid the complete reduction of the nitro group to amino. Similarly, they can be used as supports
coals

According to a preferred embodiment, the support is selected from iron and titanium oxides and combinations thereof, or active carbon.

The catalyst used in the process of the present invention may comprise at least one other metal modifier selected from one or more alkali metals or alkaline earth, preferably Li, Na, K, Cs, Fr, Mg, Ca and combinations thereof. The metal modifier is present in preferably in a weight percentage between 0.01% and 10% with respect to the support, more preferably between 0.05% and 4% depending on the content of the nature of the metal.

The supported catalyst Pt according to procedure of the present invention is preferably found in a percentage by weight between 0.01% and 10% compared to support, more preferably between 0.05% and 4%. Said Pt can be Apply in metallic or ionic form on the support. In any of both ways conventional procedures are known, known in the technique

It is important to highlight that, contrary to what what happens with the Pd catalysts proposed by Dupont in GB860340, in our case we have found that with Pt it is not required the introduction of Pb to avoid complete hydrogenation of the nitro to amino group, as long as the support and the adequate catalyst activation.

This procedure for hydrogenation Nitroalkane selective can be carried out when the, or the nitro groups, are in the presence of other functional groups reducible, such as for example aldehydes, ketones, olefins, nitriles, asters, amides, halogens, triple bonds, etc. The claimed catalysts are active and selective when support and activate properly.

In general, nitrocycloalkane has a General Formula

R-NO2

where R is a ring completely saturated or unsaturated with conjugate nitro group a hydrogenate, selected from unsubstituted rings and rings with one or more substituents. These substituents are groups selected from C1 to C8 alkyl groups, aromatic vinyl groups or C1 to C4 aliphatic, C1 to aromatic or aliphatic vinyloxy groups C4, C1 to C8 alkoxy groups, C6 H5 to C10 H8 aryloxy, fluorine groups, chlorine groups, bromine groups, iodine groups, groups hydroxy, groups with unsaturated bonds carbon-carbon groups O- (CO) -alkyl, groups O- (CO) -aryl, COOH groups, OH groups, SH groups, CN groups, SO_ {3} groups -, groups SO2 -alkyl, NH2 groups, groups NH-alkyl, NH 2 SO 2 groups, groups NSO 2 - (alkyl) 2, groups SO2 -NH-alkyl, aldehyde groups aromatic or aliphatic C1 to C4, aliphatic ketone groups or aromatic, imino group C1 to C6, ether groups C1 to C6, thioester, sulfides and combinations of same.

The term link unsaturated carbon-carbon, according to the This invention includes links to alkenes, alkynes and Alenos

The Pt / nitro molar ratio is between 0.0001 and 5%, preferably between 0.01 and 1%. Here the term "nitro" does not refer to the nitrocycloalkane compound as such but to the total number of "nitro group (s)" present in the reaction medium, there may be more than one of these groups per nitrocycloalkane molecule.

According to a particular embodiment of the procedure of the present invention, a second additional metal as a catalyst modifier preferably selected from Au, Hg, Bi, Ge, Cd, As, Sb, Mn, Co, Ti, Fe, Pd, Ru, Ni, Rh, Go, Cu, Cr and combinations of same. The weight ratio of Pt to second metal modifier is preferably between 1: 0.01 and 1: 2.

In the process of the invention the hydrogenation is done with a source of hydrogen that is a hydrogen donor molecule. Said hydrogen source is preferably selected from ammonium formate, formic acid, Decaborane, cyclohexene, cyclohexadiene, phosphoric acid and combinations thereof. According to a particular embodiment the Hydrogen source can be molecular hydrogen.

The process of the present invention is can carry out at a selected pressure between pressure atmospheric, a pressure between 1 and 100 bar, preferably between 2 and 15 bars and at a temperature between 20ºC and 250ºC, preferably between 80ºC and 150ºC.

According to a particular embodiment the procedure of the present invention is carried out under pressure atmospheric and at a temperature between 20ºC and 250ºC. Y preferably with molecular hydrogen as a source of hydrogen.

According to another additional particular embodiment the procedure is carried out at a pressure between 1 and 100 bars and at a temperature between 20 ° C and 250 ° C, preferably between 50 ° C and 200 ° C, and preferably, with molecular hydrogen as a source of hydrogen.

According to another additional particular embodiment the procedure is carried out at a pressure between 1 and 50 bars and at a temperature between 20 ° C and 150 ° C, more preferably even between 2 and 20 bars and at a temperature between 100ºC and 150ºC, and, preferably with molecular hydrogen as a source of hydrogen.

In the process according to the present invention, the hydrogenation reaction can be carried out in the presence or in the absence of solvent.

In case the procedure is performed with solvent, this can be water, alcohols, ethers, esters, ketones, carboxylic acids, aprotic dipole solvents, apolar solvents, chlorinated aromatic hydrocarbons, chloride methylene, C3-C7 alkanes, cyclohexane and combinations thereof.

In the case where the solvent is an alcohol, This may be selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isomeric butanoles, cyclohexanol and combinations thereof. In if it is an ether it can be selected from diethyl ether, methyl tert-butyl ether, tetrahydrofuran, dioxane, dimethoxyethane and combinations thereof. In the case of which is an ester may be selected from ethyl acetate, butyl acetate and combinations thereof. Supposing either a ketone may be selected from butyrolactone, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and combinations thereof. In the event that the solvent is a carboxylic acid may be selected from acetic acid, propionic acid and combinations thereof. In the event that it try an aprotic dipolar solvent, may be selected between dimethylformamide, N-methylpyrrolidine, dimethylacetamide, sulfolane, dimethyl sulfoxide, acetonitrile and combinations thereof. In the case of a solvent Apolar may be selected from toluene, xylene and combinations thereof.

Preferably, said solvent is selected from toluene, xylene, tetrahydrofuran, dioxane, methyl ethyl ketone, methanol, ethanol and combinations thereof.

The solvent can also be hydrocarbons chlorinated aromatics, methylene chloride, alkanes C3-C7, cyclohexane and combinations of same.

Said solvent serves as dissolution medium or to facilitate separation processes.

The procedure can be performed according to particular embodiments in the presence of a solvent and one or more co-solvents Said co-solvent it can be ethanol, acetone, acetonitrile and combinations of the same.

According to other embodiments of the process of the present invention, the reaction is carried out in the absence of solvent According to this embodiment, the reagents that are hydrogenated during the procedure they are preferably in phase liquid, gaseous or in coexistence of both.

In the process of the present invention, the hydrogenation reaction can be carried out in phase solid gas (catalyst), or in a system gas-liquid-solid (catalyst).

In addition, said procedure can lead to conducted in a reactor in discontinuous or continuous mode, and recovery of the catalyst can be performed by recirculation or regeneration.

The process of the present invention can further comprise a catalyst activation stage under flow of hydrogen at temperatures between 100 ° C and 600 ° C, preferably between 350ºC and 550ºC.

According to a particular embodiment of the present invention, the catalyst formed by Pt and the support is calcined at a temperature preferably between 350 and 550 ° C. The calcination can be carried out in an atmosphere of air, oxygen or hydrogen, in one or several successive stages. Preferably, the calcination is carried out under the flow of
H2.

To avoid complete reduction of the compound nitrocycloalkane to the corresponding amino compound during the step reaction temperature has a special influence on the activation temperature of the catalyst, preferably between 350 and 550 ° C under flow of hydrogen; the percentage of metal supported, preferably a Pt to support molar ratio between 0.01% and 10%; and the type of support, preferably TiO2. In addition, in order to avoid other side reactions of the oxime formed, such as its hydrolysis to cyclohexanone, it is very important to control the acidity of possible acid centers of the catalyst, for which you can use an alkali metal or alkaline earth dopant, preferably Na, K or Cs with a doping metal weight ratio at support between 0.001 and 20%.

These facts are illustrated below by specific and non-limiting examples.

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Example 1

Preparation of catalyst 0.2% Pt / TiO2 reduced to 450 ° C

The oxide-supported platinum catalyst Titanium was prepared by volume impregnation technique of pore. Platinum deposition was carried out by adding a aqueous solution of H2 PtCl6 containing the amount required of platinum on the support, so that it is impregnated with pore volume. To prepare 10 g of catalyst, 20 mL of an aqueous solution containing 53.1 mg of H 2 PtCl 6 They must be used. After homogenizing the resulting gel, the catalyst was dried in a conventional oven at 100 ° C for 6 hours. Finally, the sample was reduced under flow of H2 (50 mL / min) at 450 ° C for 3 hours.

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Example-2

Preparation of cyclohexanone oxime with H2 using the 0.2% Pt / TiO2 catalyst reduced to 450 ° C

In an autoclave, 150 mg of catalyst, prepared according to Example 1, are added to a solution of 418 mg of nitrocyclohexane in 0.55 mL of toluene, using 41 mg of o-xylene as the internal reaction standard. He air inside the autoclave is removed by purging the reactor in cold with H2 at 10 bars. With the atmospheric pressure reactor of H2, the contents of the autoclave are heated to 120 ° C and pressurizes with 10 bars of hydrogen, setting a stirring level from 1000 r.p.m. The pressure inside the reactor was maintained constant at 10 bars throughout the experiment, following the evolution of the reaction by analysis of the liquid phase by gas chromatography and mass spectrometry. After 80 minutes of reaction, cyclohexanone oxime was produced with a 62% yield.

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Example-3

Preparation of cyclohexanone oxime in the absence of solvent with H2 using the catalyst 0.2% Pt / TiO2 reduced to 450 ° C

In an autoclave, 200 mg of catalyst, prepared according to Example 1, are added to a solution of 1 g of nitrocyclohexane, using 41 mg of o-xylene as the internal reaction standard. The air inside the autoclave is removed by cold purging the reactor with H2 at 10 bars. With the atmospheric pressure reactor of H2 the autoclave content is heated to 110 ° C and pressurizes with 4 bars of hydrogen, setting a stirring level from 1000 r.p.m. The pressure inside the reactor was maintained constant at 4 bars throughout the experiment, following the evolution of the reaction by analysis of the liquid phase by gas chromatography and mass spectrometry. After 900 minutes of reaction, cyclohexanone oxime was produced with a 69% yield.

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Example-4

Preparation of catalyst 0.2% Pt / TiO2 reduced to 450 ° C and doped with 1500 ppm Na

The oxide-supported platinum catalyst Titanium and doped with Na was prepared from 0.2% material Pt / TiO2 reduced to 450 ° C indicated in Example 1 by impregnation to pore volume with an aqueous acetate solution sodium The deposition of Na on the material 0.2% Pt / TiO2 reduced to 450 ° C was carried out by adding a solution aqueous CH 3 COONa containing the required amount of Na on the catalyst, so that it is impregnated with volume of pore. To prepare 10 g of catalyst containing 1500 ppm of Na, 20 mL of an aqueous solution containing 53.5 mg of Anhydrous CH 3 COONa should be used. After homogenizing the gel resulting, the catalyst was dried in a conventional oven at 100 ° C for 6 hours.

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Example-5

Preparation of cyclohexanone oxime in the absence of solvent with H2 using the catalyst 0.2% Pt / TiO2 reduced to 450 ° C and doped with 1500 ppm of Na

In an autoclave, 200 mg of catalyst, prepared according to Example 4, is added to a solution of 1 g of nitrocyclohexane, using 41 mg of o-xylene as the internal reaction standard. The air inside the autoclave is removed by cold purging the reactor with H2 at 10 bar. With the atmospheric pressure reactor of H 2, the contents of the autoclave are heated to 110 ° C and pressurized with 4 bars of hydrogen, setting a stirring level of 1000 rpm. The pressure inside the reactor was kept constant at 4 bars during The whole experiment, following the evolution of the reaction by analysis of the liquid phase by gas chromatography and mass spectrometry. After 900 minutes of reaction, cyclohexanone oxime was produced with a yield of
74%

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Example-6

Preparation of catalyst 0.2% Pt / TiO2 reduced to 450 ° C and doped with 6000 ppm Na

The platinum catalyst supported on titanium oxide and doped with Na was prepared from the 0.2% Pt / TiO2 material reduced to 450 ° C indicated in Example 1 by impregnating pore volume with an aqueous solution of sodium acetate . The deposition of Na on the 0.2% Pt / TiO2 material reduced to 450 ° C was carried out by adding an aqueous solution of CH3COONa containing the required amount of Na on the catalyst, so that it is impregnated. at pore volume. To prepare 10 g of catalyst containing 6000 ppm of Na, 20 mL of an aqueous solution containing 214.1 mg of anhydrous CH 3 COONa must be used. After homogenizing the resulting gel, the catalyst was dried in a conventional oven at 100 ° C for 6
hours.

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Example-7

Preparation of cyclohexanone oxime in the absence of solvent with H2 using the catalyst 0.2% Pt / TiO2 reduced to 450 ° C and doped with 6000 ppm of Na

In an autoclave, 200 mg of catalyst, prepared according to Example 6, is added to a solution of 1 g of nitrocyclohexane, using 41 mg of o-xylene as the internal reaction standard. The air inside the autoclave is removed by cold purging the reactor with H2 at 10 bar. With the atmospheric pressure reactor of H 2, the contents of the autoclave are heated to 110 ° C and pressurized with 4 bars of hydrogen, setting a stirring level of 1000 rpm. The pressure inside the reactor was kept constant at 4 bars during The whole experiment, following the evolution of the reaction by analysis of the liquid phase by gas chromatography and mass spectrometry. After 820 minutes of reaction, cyclohexanone oxime was produced with a yield of
85%

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Example-8

Catalyst Preparation 0.2% Pt / TiO2 reduced to 200ºC

The oxide-supported platinum catalyst Titanium was prepared by volume impregnation technique of pore. Platinum deposition was carried out by adding a aqueous solution of H2 PtCl6 containing the amount required of platinum on the support, so that it is impregnated with pore volume. To prepare 10 g of catalyst, 20 mL of an aqueous solution containing 53.1 mg of H 2 PtCl 6 They must be used. After homogenizing the resulting gel, the catalyst was dried in a conventional oven at 100 ° C for 6 hours. Finally, the sample was reduced under flow of H2 pure (50 mL / min) at 200 ° C for 3 hours.

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Example-9

Preparation of cyclohexanone oxime with H2 using the 0.2% Pt / TiO2 catalyst reduced to 200 ° C

In an autoclave, 150 mg of catalyst, prepared according to Example 8, are added to a solution of 418 mg of nitrocyclohexane in 0.55 mL of toluene, using 41 mg of o-xylene as the internal reaction standard. He air inside the autoclave is removed by purging the reactor in cold with H2 at 10 bars. With the atmospheric pressure reactor of H2 the autoclave contents are heated to 120 ° C and pressurizes with 10 bars of hydrogen, setting a stirring level from 1000 r.p.m. The pressure inside the reactor was maintained constant at 10 bars throughout the experiment, following the evolution of the reaction by analysis of the liquid phase by gas chromatography and mass spectrometry. After 100 minutes of reaction, cyclohexanone oxime was produced with a 5.4% yield.

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Example-10

Preparation of catalyst 0.2% Pt / C reduced to 450 ° C

The carbon-supported platinum catalyst active was prepared by the volume impregnation technique of pore. Platinum deposition was carried out by adding a aqueous solution of H2 PtCl6 containing the amount required of platinum on the support, so that it is impregnated with pore volume. To prepare 10 g of catalyst, 22 mL of an aqueous solution containing 53.1 mg of H 2 PtCl 6 They must be used. After homogenizing the resulting gel, the catalyst was dried in a conventional oven at 100 ° C for 6 hours. Finally, the sample was reduced under flow of H2 pure (50 mL / min) at 450 ° C for 3 hours.

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Example-11

Preparation of cyclohexanone oxime with H2 using the 0.2% Pt / C catalyst reduced to 450 ° C

In an autoclave, 100 mg of catalyst, prepared according to Example 10, are added to a solution of 418 mg of nitrocyclohexane in 0.55 mL of toluene, using 41 mg of o-xylene as the internal reaction standard. He air inside the autoclave is removed by purging the reactor in cold with H2 at 10 bars. With the atmospheric pressure reactor of H2 the autoclave contents are heated to 120 ° C and pressurizes with 10 bars of hydrogen, setting a stirring level from 1000 r.p.m. The pressure inside the reactor was maintained constant at 10 bars throughout the experiment, following the evolution of the reaction by analysis of the liquid phase by gas chromatography and mass spectrometry. After 80 minutes of reaction, cyclohexanone oxime was produced with a 18% yield.

Claims (23)

1. A process for the selective hydrogenation of nitrocycloalkanes, substituted or not, characterized in that it comprises carrying out a catalytic hydrogenation of said compounds using a catalyst comprising at least one metal which is Pt, supported on titanium oxide, iron oxide , cerium oxide, alumina, carbon, active carbon, magnesium oxide, zirconium oxide, silica, silicic acid, lanthanum oxide, zinc oxide, calcium carbonate, calcium phosphate, calcium sulfate, barium sulfate and combinations thereof . 2. A process according to claim 1, characterized in that the catalyst further comprises a modifying metal selected from one or more alkaline or alkaline earth metals. 3. A process according to claim 2, characterized in that the alkali or alkaline earth metals are selected from Li, Na, K, Cs, Fr, Mg, Ca and combinations thereof. 4. A method according to claim 2, characterized in that the modifying metal is present in a weight percentage between 0.01 and 10% with respect to the support. 5. A method according to claim 1, characterized in that the Pt is in a weight percentage between 0.01% and 10% with respect to the support. 6. A process according to claim 1, characterized in that the nitrocycloalkane has a general formula R-NO2 where R is a ring completely saturated or with installations not conjugated with the nitro group a hydrogenate, selected from unsubstituted rings and rings with one or more substituents 7. A process according to claim 6, characterized in that said substituents are groups selected from C1 to C8 alkyl groups, C1 to C4 aromatic or aliphatic vinyl groups, C1 to C4 aromatic or aliphatic vinyl groups, C1 to C8 alkoxy groups, C_ aryloxy 6} H 5 to C 10 H 8, fluorine groups, chlorine groups, bromine groups, iodine groups, hydroxy groups, groups with carbon-carbon unsaturated bonds, O- (CO) -alkyl groups, O groups - (CO) -aryl, COOH groups, OH groups, SH groups, CN groups, SO 3 groups -, SO 2 -alkyl groups, NH 2 groups, NH-alkyl groups, NH 2 groups SO 2, NSO 2 - (alkyl) 2 groups, SO 2 -NH-alkyl groups, aromatic or aliphatic aldehyde groups C1 to C4, aliphatic or aromatic ketone groups, imino group C1 to C6, C1 to C6 ether groups, thioester, sulfides and combinations thereof. A method according to claim 1, characterized in that the Pt is applied in metallic or ionic form in the support. 9. A method according to one of the preceding claims, characterized in that an additional second metal is introduced as a modifier selected from Au, Hg, Bi, Ge, Cd, As, Sb, Mn, Co, Ti, Fe, Pd, Ru, Ni , Rh, Ir, Cu, Cr and combinations thereof. 10. A method according to claim 9, characterized in that the weight ratio of Pt to second modifying metal is in a ratio between 1: 0.01 and 1: 2. 11. A process according to claim 1, characterized in that the hydrogenation is carried out with a hydrogen source which is a hydrogen donor molecule. 12. A process according to claim 11, characterized in that the hydrogen source is selected from ammonium formate, formic acid, decaborane, cyclohexene, cyclohexadiene, phosphoric acid and combinations thereof. 13. A process according to claim 11, characterized in that the source of hydrogen is molecular hydrogen. 14. A method according to one of the preceding claims, characterized in that it is carried out at atmospheric pressure. 15. A method according to one of the preceding claims, characterized in that it is carried out at a pressure between 1 and 100 bar. 16. A process according to one of the preceding claims, characterized in that it is carried out at a temperature between 20 ° C and 250 ° C. 17. A method according to one of the preceding claims, characterized in that it is carried out in the presence of a solvent selected from water, alcohols, ethers, esters, ketones, carboxylic acids, aprotic dipole solvents, apolar solvents, chlorinated aromatic hydrocarbons, chloride methylene, C3-C7 alkanes, cyclohexane and combinations thereof. 18. A process according to one of the preceding claims, characterized in that it is carried out in the presence of a solvent and one or more co-solvents selected from ethanol, acetone, acetonitrile and combinations thereof. 19. A process according to one of the preceding claims, characterized in that the reaction is carried out in the absence of solvent. 20. A process according to one of the preceding claims, characterized in that the hydrogenation reaction is carried out in the gas-solid phase. 21. A process according to one of the preceding claims, characterized in that the hydrogenation reaction is carried out in a gas-liquid-solid system. 22. A method according to one of the preceding claims, characterized in that it is carried out in a reactor selected between reactor in discontinuous mode and reactor in continuous mode. 23. A process according to claim 1, characterized in that it further comprises a step of activating the catalyst under hydrogen flow at temperatures between 100 ° C and 600 ° C.