MXPA00005899A - Process for hydrogenation of macromolecular organic substrates - Google Patents

Abstract

A process for the hydrogenation of a macromolecular organic substrate which process comprises contacting the organic substrate at elevated temperature and at elevated pressure with a catalyst comprising a hydrogenating metal or precursor thereof, in the form of a megaporous structure having megapore diameter in excess of 10 micron.

Description

PROCESS FOR THE HYDROGENATION OF MACROMOLECULAR ORGANIC SUBSTRATES DESCRIPTION OF THE INVENTION The present invention relates to a process for the catalytic hydrogenation of macromolecular organic substrates. More specifically, the present invention relates to heterogeneous processes for the catalytic hydrogenation of macromolecular organic substrates in fixed bed operations. The processes for the hydrogenation of organic substrates are well known. A particular class of organic substrates is desired, to hydrogenate this class of oligomers and polymers, and in particular in the subclass of the elastomers. The polymer SBS (styrene-butadiene-styrene) has been hydrogenated commercially for 25-30 years, and is sold as a range of elastomers with a high added value of improved stability. The SBS polymer is soluble in organic solvents to provide a highly viscous solution (the so-called polymer cement) which offers great spherical inhibition to the catalysts. As a consequence, to date hydrogenation processes have employed nickel / aluminum colloidal catalysts placed in REF.120632 contact at 80 ° C and 60 bar of hydrogen with the dissolved elastomer. Unfortunately, the catalyst system is prone to the formation of metal residues during the reaction stage, which remain in the polymer cement and contaminate the product. Accordingly, a subsequent step is usually employed for the removal of the metal waste. To date, efforts have focused on minimizing the level of ash in the product. However, the metal waste removal stages remain singularly responsible as the largest contributors of capital costs in these commercial systems. Previous attempts to employ catalysts that are not prone to waste formation have been less than successful. It is known that heterogeneous catalyst systems show lower activities that have to be compensated by higher reaction temperatures in the order of magnitude of 200 ° C. Unfortunately, the reaction under these conditions results in deterioration of the molecular weight of the product, and in the contamination of the product with the metal as a result of the degradation of the catalyst. In EU 5,378,767 a process is described comprising a fixed bed hydrogenation of polydiene polymers of MW up to 10,000, wherein the fixed bed comprises platinum, palladium or a mixture of both which are supported by alpha alumina support particles of Size-mm in a fixed bed at elevated temperatures and in the magnitude of 200 ° C with high conversion. However, it is noted that some degradation of the polymer is observed due to the severe conditions employed. The heterogeneous processes for the hydrogenation of low MW organic substrates are known. The heterogeneous process of EP 0 233 642 has the purpose of improving the selectivity of the hydrogenation of non-viscous substrates of low molecular weight, comprising vegetable oils of one MW in the range of 600-1400 and viscosity typically in the region of less than 10 cps at an operating temperature in the region of magnitude of 135 ° C. Oils which are believed to be trapped in the fixed-bed catalytic structures, saturated with hydrogen and fully hydrogenated, can instead be partially hydrogenated with catalysts comprising a lamella or briquette, which provide an easy exit of the partially hydrogenated intermediate. As a consequence, this publication only teaches that the lamella and honeycomb-forming catalysts can give an improvement in the selectivity of the conversion of a food of low viscosity and low molecular weight, but does not give information on its applicability to convert high MW substrates. (of the magnitude of X 100) and high viscosity (of the magnitude of X 100). Even more organic substrates such as oligomers and polymers and in particular the subclass of elastomers are sensitive to non-selective hydrogenation resulting in deterioration of physical and chemical properties and the like. From the Patents of E. U. Nos. 5, 028,665 and 5,110,779 a heterogeneous catalyst comprising a Group VIII metal and a porous support is known, wherein the porous support is characterized by a pore size distribution such that at least 95% of the pore volume is defined by pores having diameters greater than 450 angstroms and the ratio of metal surface area to carrier surface area is in the range of about 0.07-0.75: 1. These processes, however, use catalyst particles that have relatively small particle sizes of 10-20 microns that are made slurry in the polymer solution, and although they can be separated from the hydrogenated polymer solution by conventional methods such as precipitation, Centrifugal filtration separation, separation of the catalyst and its fine particles from the highly viscous polymer solution is not an easy and hardly perfect task. Finally, processes for the hydrogenative conversion of organic substrates are known to obtain other useful products having different characteristics in the chemical and physical properties. For example, it is known that polyketones can be converted to oli alcohols with the use of conventional hydrogenation catalysts. Accordingly, there is a need for a hydrogenation process to convert organic substrates which is capable of selectively hydrogenation of a wide range of substrates, without the need to remove residues of the hydrogenation metal from the product, and without deterioration of the weight molecular of the product or contamination by the degradation of the catalyst or similar, and that is adapted for its commercial operation. Surprisingly we have found that a process for hydrogenation can be provided with the use of a catalyst substantially resistant to degradation that is not prone to the formation of metal residues, and which allows intimate contact with the active metals of hydrogenation or its precursors or the macromolecular organic substrates, whereby the reactions can be carried out under non-extreme conditions which are not harmful in terms of the physical and chemical properties of the hydrogenated product, in particular the reduction in molecular weight of the macromolecular substrates. Moreover, the processes can be used for the hydrogenative stabilization of the unsaturated substrates or for the hydrogenating conversion in other useful substrates. In its broadest aspect, according to the present invention, there is provided a process for the hydrogenation of a macromolecular organic substrate comprising contacting the organic substrate at a high temperature and pressure with a catalyst comprising a hydrogenating metal or precursor thereof in the form of a megaporous structure having a megapore diameter in excess of 10 microns. The megapore structure can be selected from any structure known in the art, preferably comprising structures that provide a maximum volume fraction of metal (precursor) in a thin layer of sub-mm surface, with a maximum of the remaining fraction of volume available as a vacuum for the substrate. Preferred structures are those for which the optimum vacuum fraction that is available to the substrate for any volume of thin layer catalytic metal has been found. Preferably the structure comprises open-end megapores that provide an optimal transfer of mass and convection. The megaporous structures may comprise a carrier for the supported metal, or may comprise the unsupported metal itself, for example shaped, with an optional reinforcement as is known in the art. The megapore structure may be selected from any fixed bed structure comprising a structured packing such as a side-stream serial bead pack., and parallel input and the like, or comprising a monolith, as described in S. T. Sie, J. E. Naber, Parallel p Assage and Lateral Flow Reactors, in Structural Catalysts and Reactors, ed. by A. Cybulski and JA Moulijn, and in * Monoliths in Heterogeneous Catalysts ", Cybulski et al, Catal. Rev. Sci. Eng., 36 (2), 179-270 (1994) and 'Monolithic Ceramics and Heterogeneous Catalysts: Honeycombs and Foams ", Car and and Lednor, Catalysts and Porous Solids, Current Opinion in Solid State & Materials Science 1996, 1: 88-95, with extensive reviews of suitable support materials as are known in the art, together with methods for the preparation thereof, the contents of which are incorporated herein for reference.The structures suitable for use in the processes are commercially available. Preferred forms for the catalyst include packaged lamella, such as corrugated or flatly spaced lamellae that can be stacked or rolled, shaped into wire mesh honeycombs and foam monolith structures, and other structures that have high mass transport.

The reference herein for macromolecular organic substrates is for any substrate that contains a characteristic molecular weight and viscosity unsuitable for intimate contact in known heterogeneous systems. In particular substrates comprising natural or synthetic oligomers or polymers such as the macromolecule or part thereof having a molecular weight (MW) of average number of the magnitude of at least 1000 is conceived. It is a particular advantage of the present invention that the process is ideally suited for hydrogenation in high-quality liquid phase, optionally dissolved, and macromolecular substrates as defined herein above by having molecular weights in the range of at least I x l03 alx l07 or more, and with particular advantage in the range of 1 x 105 to 5 x 105. The viscosity of macromolecular substrates can be adapted for the proper selection of similar solvents to minimize the effects of polymer chain entanglements, weak chain or ion bond (H-) interactions and what looks like, but the process of the invention is of particular advantage for viscosity macromolecules in the range from 10 to 5000 cps at operating temperature, and in particular in the range of 100-500 cps at operating temperature. The homogeneous processes described hereinbefore for the hydrogenation of macromolecular substrates, and the heterogeneous processes described hereinabove for the hydrogenation of low MW substrates are believed to operate by a totally different mechanism than the heterogeneous process of the invention. In particular, homogeneous catalysts can be expected to penetrate to great depths in macromolecular substrates. Accordingly, attempts to reduce the contamination of the product by metallic residues of the catalyst, by employing heterogeneous catalysts which are not prone to form metallic residues, are expected to be limited in their success due to a restricted access of the spherical inhibition of the catalyst. catalyst to sites for hydrogenation within the macromolecule. In particular, it can be thought that this is the case for molecules comprising polymers that are typically in the form of long surface chains folded or other reduced forms. Without being limited by this theory, it is believed that the combined effects of wetting or solvation by the macromolecular substrate or its solvent on the surface of the catalyst and the dynamic properties of the macromolecule, in particular the chain-like macromolecules such as natural polymers and synthetic, allow the macromolecule to deform, settle or deploy on the catalyst surface whereby substantially all of the theoretical surface area of the macromolecule is adapted to contact the surface of the catalyst. It is also believed that macromolecules are restricted from entering the micro-macropores of the catalysts due to the molecular size and viscosity of these, for which reason it can be expected that the molecules are associated with properties of very low diffusion, however the the megapore of the catalyst used in the process of the invention provide a high mass transfer, whereby a degree of convection supplements the diffusion inside and outside the megapores, facilitating the contact of the macromolecules with the hydrogenating metal.

The selectivity illustrated in the process of the invention indicates that the hydrogenation in fact proceeds by catalytic means. The process of the invention can be used for selective or complete hydrogenation of any unsaturated macromolecular substrate as defined hereinbefore for the stabilization of these or for conversion to new products having the desired chemical and / or physical properties. The process is of particular advantage in the hydrogenation of substrates, natural or synthetic, such as polymers selected from conjugated diolefins and conjugated substances and alkenyl copolymers and functional derivatives thereof, aromatic polyesters and polycarbonates and the like. Conjugated diolefins include those containing from about 4 to about 24 carbon atoms such as 1,3-butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl. -l, 3-octadiene and what it looks like, of which isoprene and butadiene are in common use for their low cost and easy availability. The alkenyl aromatic hydrocarbons include vinyl aryl compounds such as styrene, substituted alkyl styrenes, substituted alkoxy styrene, vinyl naphthalene, substituted vinyl naphthalene alkyls and the like. The co-polymers of diolefins and aromatic substances alquenilas comprise aromatic substances alquenilas co-polymerized in block or randomly with conjugated diolefins as defined hereinabove. Conjugated diolefins and / or aromatic alkene compounds as defined herein above also include functional derivatives that comprise various functional groups such as a randomly added hydroxyl group or at the ends of a star or branched polymer; and mono-, di-, tri-, blocks, etc., of these polymers. Preferred substrates are styrene-containing polymers such as elastomers (in the range of Kraton ™). The polyketones include alternating linear polymers of high molecular weight of carbon monoxide with unsaturated olefin compounds, which may comprise a heteroatom, optional aromatic and / or cyclic groups which are suitable for the conversion of the corresponding polyalcohol. Preferably they are carbon monoxide polymers with an alpha or cyclic olefin, and more preferably with an alpha olefin having for many six carbon atoms, for example ethene, propene, 1-butene and the like. Preferred polyketones are characterized by, for example, a molecular weight (MW) of average number in excess of 1000, or a number of limited viscosity of 0.2-5.0 dl / g, preferably 0.3-4.5 dl / g in metacresol at 60 ° C, with a melting temperature in the range of 150-270 ° C determined by differential scanning calorimetry. Polyketones that are particularly suitable for conversion by hydrogenation to a corresponding polyalcohol are commercially available as Carilon ™ polymer and Carilite ™ thermosetting resin having a respective MW of about 10,000+ and between about 1000-5000. The hydrogenation metal that is employed can include any metal or known combination thereof adapted for catalytic hydrogenation, typically comprising an element selected from Groups 7-11 of the Periodic Table of Elements and mixtures thereof, optionally with additional metals, for example selected from Groups 1-6 and 12-14 of the Periodic Table. Preferably the hydrogenation metal is selected from one or more elements of Groups 8-11 of the Periodic Table, most preferably Fe, Co, Cu, Ni, Pd, Pt, Ru and mixtures of esters, optionally with other metals of Groups 6 and 7 of the Periodic Table, for example Cr. The metals can be selected according to the desired selectivity and the substrate to be hydrogenated.

The catalyst may comprise the catalytically active metal in any suitable amount to achieve the level of activity required. Typically, the catalyst comprises the active metal in an amount in the range of 0.1-100% by weight, preferably 0.01-20% by weight when supported on a carrier, and most preferably from 0.1-10% by weight, and more preferably from 1-7.5% by weight; or 80-100% by weight when it is substantially unsupported. The techniques for forming metals or supporting metals in porous structures are well known in the art, for example impregnation or (in a metallic structure) of electrolytic position. A very suitable technique for supporting the metal in a megaporous structure is impregnation. Preferably the impregnation of the structure is with a solution of a compound of a catalytically active metal, followed by a drying and calcination of the resulting material. Where it is desired to introduce a mixture of metals or a mixture with additional metals as described hereinabove, the impregnation solution can be a mixture of solutions that the respective salts of the metals combined in an amount suitable for co-impregnation. In another case, the impregnation can be sequential, with a first stage impregnation, drying and calcination with the solution of the catalytically active metal, and a second stage impregnation of another metal to be impregnated, or vice versa. Preferred techniques for impregnation are soaking, painting, spraying, immersion, application by means of a quantized droplet and what looks like a solution or suspension of the catalytically active metal, with a subsequent drying in hot air or the like and optionally a calcination , so that a uniform impregnation is achieved. Preferably the impregnation and / or drying is carried out in the absence of distorting capillary effects of gravitation during drying, which may provide a gradient or undesirable total content of the impregnated metal. For example, the megaporous structure can be rotated or suspended in a way that contact with other objects does not induce capillary or meniscus effects.

The hydrogenating metal is suitably impregnated in the form of a suboxide, or converted to the oxide during the calcination step. Preferably the metal oxide is converted to its catalytically active form by reducing it to the metal, using techniques that are known in the art. For example, the catalyst may be charged to the reactor and a stream of hydrogen may be passed over the catalyst at elevated temperature for a sufficient period of time to convert a sufficient amount of the impregnated metal oxide to its metallic form. A megaporous structure as defined herein above suitably comprises any temperature resistant and degradation resistant material, which is commercially available, or which can be prepared by techniques that are well known in the art. Examples of suitable materials include metals (for example steel and / or the hydrogenating metal itself); carbon; Inorganic metal oxides such as silica, alumina, titania, zirconia, and mixtures of these (this is inorganic metal oxides comprising at least one cation, or at least two cations, being a binary oxide, ternary oxide, etc.); metal carbides; nitrides and the like. In at least one cation of a metal inorganic oxide support preferably is selected from Groups 2-4 and 12-14 of the Periodic Table of the Elements and the lanthanides. A mixed oxide may comprise two or more cations in any desired amount preferably in each independently of an amount of 1-99% wt, and most preferably two cations in an amount of 1-50% and 50-100% wt, respectively, and more preferably in an amount of 15-25% and 85-75% wt, respectively. The oxide is prepared adequately by techniques that are well known in the art or commercially available. The megaporose structure comprises the catalytically active metal distributed over its surface area. Preferably the structure is provided with an intensified surface area, by means of a coating, a washing layer or similar layer of porous material introduced by techniques that are known in the art. For example, in "Monolithic Ceramics and Heterogeneous Catalysts" as described herein above, techniques described for coating foams with oxide layers that can be used to increase the surface area or to alter the surface conditions are discussed. by washing it is typically coated with alumina, preferably by means of an alumina sol, or with perovskites, by coating the foams first with an epoxy resin, then by infiltration with perovskite powder. carriers coated with a wash that provides a 10% improvement over the carriers that were not coated with wash in terms of conversion.

The oxide support may comprise circumstantial amounts of other cations, present as a result of the synthesis of these or for a functional purpose. The megapore structure preferably comprises a large number of megapores as described hereinabove. In this respect, the term "pore" is a general reference to a space or gap in the fixed configuration between two adjacent portions of the catalyst, therefore, in the case of a fixed bed comprising a structured packing, the term wporo " refers to the space between two adjacent packaging components. When referring to monoliths, the term "pore" refers to the openings or spaces between adjacent portions or regions of the monolith. Therefore, it is appreciated that the pores referred to with respect to the present invention have a nominal diameter in the order of magnitude of at least 10 microns, preferably from 0.1 to 10 mm. This has to be contrasted with the pores that may be present in the megaporous structure material itself, which may have pores. The pore size can be selected according to the MW and viscosity of the substrate or solution of which it is desired to hydrogenate. The megapore structure preferably comprises up to 50 pores per linear inch (ppi) (20 pores per linear cm), and more preferably from 10 to 30 ppi (4 to 12 pores per linear cm), and especially from 12 to 25 ppi ( 5 to 10 pores per linear cm), for example about 20 ppi (approximately 8 pores per linear cm). Any suitable reaction regime can be applied in the process of the present invention in order to contact the reactants with the catalyst. A suitable regimen is a rotary bed, wherein the catalyst is used in the form of a bed mounted on a rotor immersed in the substrate. An alternative reaction regime for use in the process is a reaction regime of a substrate in a reaction zone in a fixed configuration. The process is carried out under conditions of high temperature and pressure as defined hereinbefore, suitably in the range of 40-400 ° C, preferably 80-200 ° C and a hydrogen gas pressure in the range of 10-120 bar, preferably 40-80 bar. The reaction is suitably carried out as a batch, a semilote or a continuous process under conditions with a residence time which is chosen for the desired selectivity and conversion of the reaction.

The reaction is preferably carried out, as here described above by the use of an agitation of the reactor contents. In the case where the catalyst is mounted on a rotating blade inside the reactor, the reaction is suitably carried out at a rotor agitation speed in the 800-1200 rpm range. In the case where the catalyst is in a fixed bed the flow rate can be selected to achieve the desired selectivity and conversion of the reaction. The substrate to be hydrogenated in the liquid phase that is diluted or not diluted adequately to achieve the desired viscosity.

The catalyst and conditions can be adapted with reference to the nature of the substrate, and depending on its sensitivity to temperature, viscosity and suitability for selective or complete hydrogenation and the like. The reaction is terminated by cooling and releasing the gas under pressure. The contents of the reactor are suitably removed in an inert container and removed by solvent by techniques that are known in the art. The invention is now illustrated in a non-limiting manner with reference to the following examples.

Example 1 Examples of monolithic alumina foam 20 ppi. Cylindrical (h50 mm, w55 mm), and commercially available are loaded with either 5% Ni or 5% Cu. Other examples with a specific surface area increased include monolithic alumina foam with a wash layer of 5-6% HPA, a mixture of calcined hydrated alumina. The ceramic foam cylinders are dried at 120 ° C for at least one hour before their impregnation. Solutions of known concentrations of copper, nickel and chromium nitrates are prepared and added to the ceramic foam in sufficient quantities to give the desired fillers. The addition of the solution was carried out partially by dripping, and by immersing the foam in the solution. After each addition the foam dries. The material is then placed in an oven equipped with a fan and dried / calcined using the following temperature program: 4h / 120 ° C, heated to 540 ° C to 500 ° C, and maintained for one hour at this temperature, it is cooled to 120 ° C, and removed from the oven.

Example 2 The monolithic alumina foam is mounted in the agitator of an autoclave. The nickel oxide is reduced to metallic nickel by passing hydrogen over the foam at 200 ° C. At room temperature 160 grams of a cement precursor G-1650 (PM 71600 SBS) in cyclohexane are added and the autoclave is pressurized with hydrogen at 60 bar. The autoclave is heated to 120 ° C reaction temperature and maintained for 8 hours. The reaction is terminated by cooling the autoclave and venting the hydrogen. The autoclave opens and the contents are poured at an aluminum rate. The solvent is evaporated in a steam bath subsequently by a vacuum at 30 ° C overnight. The conversion and selectivity is determined by Rtwjl spectroscopy. The same catalyst is reused for subsequent reactions and reduced for each condition. The GPC and ICP-MS analysis of the products from the monolithic foam experiment according to the above method showed no degradation of the polymer and no nickel is leached from the monolithic support.

Example 3 A coated foam is analyzed by washing impregnated with 5% w nickel under the same conditions of Example 2 as the foam that is not coated by washing. This foam covered with washing, with an increased surface area, which is converted to polybutadiene for 72% and polystyrene for 33% at 120 ° C, 60 bar of H2 and for 8 hours of reaction time. The overall performance of the foam coated with the nickel impregnated wash is 10% relative better than the non-coated foam with washing.

Example 4 A monolithic alumina foam impregnated with 5% w copper chromium + 0.005% w is analyzed using the process of Example 2. This foam provides a similar hydrogenation of the polybutadiene but no hydrogenation of the styrene is observed. The polybutadiene is converted for 60% in 7.5 hours at 120 ° C, 60 bar H2 and 1200 rpm.

Example 5 A monolithic alumina foam impregnated with 1% w platinum (ex PtCl.) Is analyzed using the process of Example 2, using 180 grams of a G-1650 cement precursor (PM 71600 SBS) in cyclohexane.

The hydrogen pressure is set at 50 bar. After hydrogenation, in most cases a two-phase system is formed after some time. The separation of the phases produces different conversions for the phases. The phase having the highest conversion produces a polymer having a polybutadiene conversion of > 99% and a polystyrene conversion of > 98%. The invention shows that the megaporous catalysts based on ceramic foams are capable of hydrogenating the SBS polymer without contaminating the product with metal residues.

Example 6 Example 5 is repeated, however, using 160 grams of polystyrene (i EM 35000) in cyclohexane and applying a reaction temperature of 180 ° C. The total conversion is achieved in 8 hours. The results of Examples 2 to 5 are shown in Table 1, where in each experiment, the No. 1 test series is not recorded for the fresh catalyst. In Table X (s) and X (bd) indicates the conversion or percentage of hydrogenation of styrene and butadiene respectively.

Example 7 The experiments are carried out with a foam, a-A1203 with a pore size of 40 ppi. The foam weighs 39.4 g and is shaped as a hollow cylinder with a diameter of 4.3 cm, and an external diameter of 6.5 cm and 4.2 cm in height. The foam is impregnated with 2 w% Ru (III) nitrosyl nitrate and calcined at 400 ° C.

The catalyst is mounted in a 300 ml autoclave which is equipped with an electric heating jacket and is agitated by a gas distribution propeller. The catalyst is reduced for 17 h at 130 ° C under 5 bar of H2 with a regular purge and renewal of the H2 gas phase. The food consists of Carilite ™ EP, an alternating co-polymer of CO and propylene of which 50% of the propylene has been replaced by ethene. The weight The molecular weight of Carilite is Mn = 35.02 and Mw = 6956. 13.95 g of Carilite are dissolved in 122.46 g of THF (tetrahydrofuran) and 13.29 g of water. The entire mixture is pumped into the autoclave against 50 bar of H2 and at 150 ° C within approximately 1 h. The H2 pressure is then raised to 90 bar and the reaction is carried out for 17 hours with a regular sampling of the liquid product. At the end of the reaction the clear and colorless liquid is concentrated by evaporating the THF solvent and the water under a vacuum. The resulting sticky white mass is then dissolved in an equivalent mass of CD3OD and an equivalent mass of DCC13 and analyzed by infrared spectroscopy using NaCl cell windows.

The conversion as quantified by the proportion between the band of C = 0 dilated around 1590-1800 cm "1 and the CH bands that dilate around 2750-3050 cm-1 reach already 94% after two hours of reaction and is completed after 17 hours.At the same time a strong OH band that dilates and develops at 3050-3700 cm-1.

Table 1 Hydrogenation of Kraton G-1650 with Monolithic Foams From the results it is clear that monolithic foams impregnated with nickel are able to hydrogenate the polybutadiene but also hydrogenate the polystyrene to some degree. The monolithic foams impregnated with platinum were able to better hydrogenate the polystyrene. In Example 2 the ratio X (s): X (bd) remains between 0.4 and 0.6 which indicates that the selectivity is independent of the reaction parameters. The monolithic foams impregnated with copper provide, in comparison with nickel, a similar level of hydrogenation of the polybutadiene but there was no hydrogenation of the polystyrene. This indicates that the selectivity can be determined by the choice of metal. It is noted that in relation to this date, the best known method for the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (10)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A process for the hydrogenation of a macromolecular organic substrate characterized in that the process comprises contacting the organic substrate at an elevated temperature and high pressure with a catalyst comprising a hydrogenating metal or a precursor thereof, in the form of a megaporous structure which It has a megapore diameter in excess of 10 microns.

2. A process according to claim 1, characterized in that, the megapore structure is a monolith, more preferably it comprises a packed foil, such as a corrugated or flatly spaced foil that can be stacked or rolled up, and a honeycombed mesh conformation. wire and monolithic foam structures.

3. A process according to claim 1, characterized in that the hydrogenation metal comprises an element selected from Groups 7-11 of the Periodic Table of Elements and mixtures thereof, optionally with added metals selected from Groups 1- 6 and 12-14 of the Periodic Table.

A process according to any of claims 1 to 3, characterized in that the metal is present in an amount in the range from O.Ol-KXSé. by weight of catalyst, preferably from 0.1-20% or 10% and more preferably from 1-7.5% when it is supported by a carrier and from 80-100% when it is not supported.

A process according to claim 1, characterized in that the megaporous structure comprises a material substantially resistant to degradation and resistant to temperature, selected from metals, carbon, inorganic oxides of metal, carbides and metal nitrides.

A process according to claim 5, characterized in that the megaporose structure comprises an inorganic metal oxide containing at least one cation, selected from Groups 2-4, and 12-14 of the Periodic Table of Elements.

7. A process according to claim 1, characterized in that the catalyst is provided with an improved surface area > By means of a coating, wash coating or similar layer of porous material.

8. A process according to claim 1, characterized in that the fixed configuration of the catalyst has pores in the range from 0.1 to about 10. Omm.

9. A process according to claim 1, characterized in that the macromolecular substrate or part thereof is selected from natural and synthetic oligomers or polymers having a molecular weight of at least I x l03 alx l07 or more, preference from 1 x 105 to 5 x 105 and / or a viscosity in the range from 10-5000 cps at operating temperature ..

10. A process according to claim 1, characterized in that the organic substrate is selected from conjugated diolefins and aromatic substances and co-polymers alkenyls and functional derivatives thereof, polyketones, polyesters and aromatic polycarbonates. A process according to claim 1, characterized in that the substrate is contacted with the catalyst at a pressure in the range of 10-120 bar, preferably from 40 to 80 bar and a temperature in the range from 40 to 400 °. C, preferably from 80 to 200 ° C with the stirring or flow of the contents of the reactor.