PROCESS FOR PREPARING AN IZM-2 BASED CATALYST BY A SPECIFIC HEAT TREATMENT AND USE OF SAID CATALYST FOR ISOMERIZING PARAFFINIC FILLERS IN MEDIUM DISTILLATES

Abstract

The present invention relates to a process for preparing a bifunctional catalyst using an IZM-2 zeolite, a hydrogenating function, and a matrix. The preparation process according to the invention employs a specific heat treatment of the catalyst that improves its selectivity for the isomerization of paraffinic feedstocks into middle distillates.

Description

Title of the invention: METHOD FOR PREPARING AN IZM-2 BASED CATALYST BY A SPECIFIC HEAT TREATMENT AND USE OF SAID CATALYST FOR ISOMERIZING PARAFFINIC FILLERS IN MEDIUM DISTILLATES technical field

[0001] In order to meet the demand for middle distillate bases, i.e. in a cut that can be incorporated into the kerosene and / or diesel pool, various methods of producing middle distillates based on the use of petroleum, natural gas or renewable resources can be implemented.

[0002] Middle distillate bases can thus be produced from a paraffinic feedstock obtained from a feedstock derived from renewable sources, and in particular from vegetable oils or animal fats, crude or pre-treated, as well as mixtures of such feedstocks. Indeed, said feedstocks from renewable sources contain chemical structures of the triglyceride, ester, or free fatty acid type, the structure and hydrocarbon chain length of the latter being compatible with the hydrocarbons present in the middle distillates. After hydrotreatment, said feedstocks from renewable sources produce paraffinic feedstocks free of sulfur compounds and aromatic compounds. These paraffinic feedstocks are typically composed of linear paraffins having a number of carbon atoms between 9 and 25.

[0003] Middle distillate bases can also be produced from natural gas, coal, or renewable sources via the Fischer-Tropsch synthesis process. In particular, the so-called low-temperature Fischer-Tropsch synthesis using cobalt catalysts makes it possible to produce essentially linear paraffinic compounds with a highly variable number of carbon atoms, typically from 1 to 100 carbon atoms or even more. Separation steps can be used to recover paraffinic feedstocks with a number of carbon atoms between 9 and 25.

[0004] However, these middle distillate bases obtained after hydrotreating vegetable oils or after the low-temperature Fischer-Tropsch synthesis process cannot generally be incorporated as such into the kerosene or diesel pool, particularly due to insufficient cold-weather properties. Indeed, the high molecular weight paraffins, which are linear or very weakly branched and which are present In these basic, middle distillates, high pour points are necessary, leading to freezing phenomena for low-temperature applications. For example, the pour point of a linear hydrocarbon containing 20 carbon atoms per molecule and with a boiling point of approximately 340°C—typically within the middle distillates range—is approximately +37°C, making its use impossible, as the specification for diesel fuel is -15°C. To reduce pour point values, these linear or very weakly branched paraffins must be completely or partially eliminated.

[0005] This operation can be carried out by extraction using solvents such as propane or methyl ethyl ketone; this is referred to as dewaxing with propane or methyl ethyl ketone (MEK). However, these techniques are expensive, time-consuming, and not always easy to implement.

[0006] Selective cracking of the longest linear paraffinic chains, which leads to the formation of lower molecular weight compounds, some of which can be removed by distillation, provides a solution for reducing pour point values. Given their shape selectivity, zeolites are among the most widely used catalysts for this type of process. The most commonly used catalyst in the selective cracking dewaxing category is ZSM-5 zeolite, of the MFI structural type, which exhibits three-dimensional porosity with medium pores (opening at 10 oxygen atoms, 10MR). However, the cracking in such processes leads to the formation of significant quantities of lower molecular weight products, such as butane, propane, ethane, and methane, which considerably reduces the yield of the desired products.

[0007] Another solution for improving cold stability is to isomerize long linear paraffins while minimizing cracking. This can be achieved by implementing hydroisomerization processes using bifunctional catalysts. Bifunctional catalysts involve a Brønsted acid phase (e.g., a zeolite) and a hydro / dehydrogenating phase (e.g., platinum), and generally a matrix (e.g., alumina). The appropriate choice of the acid phase promotes the isomerization of long linear paraffins and minimizes cracking. Thus, the shape selectivity of one-dimensional medium-pore (10MR) zeolites, such as ZSM-22, ZSM-23, NU-10, ZSM-48, and ZBM-30, makes their use particularly suitable for obtaining catalysts selective for isomerization.

[0008] Recently the applicant also discovered that the use of IZM-2 zeolite is also suitable for obtaining catalysts selective towards the isomerization of long paraffins. Prior art

[0009] However, it is well known that factors other than the acid phase have an impact on the activity and selectivity of a bifunctional catalyst. Hydroisomerization and hydrocracking of normal paraffins have thus been the subject of numerous academic studies since the original work of Weisz or Coonradt and Garwood in the 1960s. The most commonly accepted mechanism involves first the n-paraffin being dehydrogenated to n-olefin in the hydro-dehydrogenating phase and then, after diffusion to the acid phase, being protonated to carbenium ions. After structural rearrangement and / or [3-cleavage], the carbenium ions desorb from the acid phase as olefins after deprotonation. Then, after diffusion to the hydro-dehydrogenating phase, the olefins are hydrogenated to form the final reaction products. When maximum selectivity in isomerization is sought, it is necessary to limit cracking reactions on the acid phase.It is therefore necessary to have a hydro / dehydrogenating function that is sufficiently active with respect to the acid function, and sufficiently close to the acid function, to rapidly hydrogenate the olefinic intermediates. When the overall reaction rate is controlled solely by the steps catalyzed by the acid function, the bifunctional catalyst is said to be "ideal." In this case, for a given acid function, the activity and isomerization selectivity of the catalyst are then dictated by the properties of the acid phase. This case is well known and reported in the academic literature, for example, in the case of the isomerization of long paraffins such as n-hexadecane (see, for example, PSF Mendes et al., AIChE Journal, 63 (2017), 7, 2864-2875 and references cited). However, the hydro / dehydrogenating function can also catalyze reactions such as the hydrogenolysis of paraffins.This reaction is undesirable because it can lead to a decrease in the isomerization selectivity of the bifunctional catalyst. Industrial bifunctional catalysts using a zeolite as the acid phase and a noble metal as the hydrogenating function are typically prepared by shaping the zeolite with a matrix, which may be alumina, to obtain a shaped support, and then impregnating the metal phase onto this support. Generally, the heat treatment steps associated with shaping the support and deposition of the metal function involve contacting the solid with a gas that may contain oxygen (in the case of calcination) or hydrogen (in the case of reduction).Generally, these heat treatment steps are carried out in the absence of chlorine or chlorinated compounds and water in the gaseous medium, in order to preserve the crystalline structure of the zeolite and prevent its desalination. The resistance of zeolite to desalination depends on its structure and its form (acidic or non-acidic). The temperature and the presence of chlorine or chlorinated compounds and water are factors (see R. Lopez-Fonseca et al., Applied Catalysis B: Environmental 30, (2001), 303-313 and Z. Konya et al., Applied Catalysis B: Environmental, 8 (1996), 391-404). Heat treatments using chlorine or chlorinated compounds in the gaseous medium are reported in the context of regenerating spent catalysts containing a noble metal and a zeolite. These treatments aim to redisperse the noble metal that may have sintered during catalyst use. These so-called oxychlorination heat treatments are carried out after an initial controlled calcination heat treatment of the spent catalyst, which aims to remove the coke present on the spent catalyst.

[0010] Patent application WO94 / 05419 discloses a regeneration protocol for a reforming catalyst employing a Group VIII metal and a zeolite. This regeneration protocol includes a combustion step to remove coke followed by heat treatment in the presence of water, a chlorine source, oxygen, and an inert gas.

[0011] French patent FR2874516 discloses a process for regenerating a catalyst comprising at least one zeolite with structural code EUO and at least one hydro-dehydrogenating metal. This process includes a step of removing most of the coke by combustion in the presence of an oxygen-containing gas at less than 600°C, followed by an oxychlorination step in the presence of a gaseous mixture containing at least water, oxygen, and chlorine and / or at least one chlorinated compound.

[0012] US patent 4,645,761 discloses a protocol for rejuvenating a catalyst comprising an alumina matrix, a noble metal and a zeolite with a silica-to-alumina molar ratio of at least 20. This protocol includes a step of reducing the catalyst under hydrogen followed by a step of redispersing the metallic phase in the presence of a gas containing 1 to 20% by volume of oxygen and 0.001 to 10% by weight of hydrogen halide.

[0013] Patent WO9847615 discloses a process for improving the catalytic activity of a catalyst containing a type L zeolite and at least one Group VIII metal. This process comprises contacting said catalyst with a gaseous medium comprising water, a chlorine source, oxygen, and an inert gas at 450 to 550°C. The resulting product is then contacted with a gaseous medium comprising water, oxygen, and an inert gas at 450 to 550°C to reduce the chlorine content of the catalyst to less than 2% by weight. Finally, the solid is reduced between 350°C and 550°C by a hydrogen-containing gas and an inert gas to obtain the metal in its reduced form.

[0014] During his work to improve the selectivity in isomerization of long paraffins and the activity of bifunctional catalysts using IZM- zeolite 2 as an acid function, the applicant discovered a surprising impact of the catalyst preparation protocol on the isomerization selectivity of said bifunctional catalysts using IZM-2 zeolite, the activity of said catalysts being at least maintained.

[0015] Thus, the present invention relates to a process for preparing a bifunctional catalyst using an IZM-2 zeolite, a hydrogenating function comprising at least one noble metal from group VIII and a matrix.

[0016] Another object of the present invention relates to the catalyst obtained by said process.

[0017] Another object of the present invention relates to a process for isomerizing paraffin fillers from hydrotreated vegetable and / or animal oils or from low-temperature Fischer-Tropsch synthesis, said process implementing said bifunctional catalyst.

[0018] Surprisingly, the preparation process of the invention improves the isomerization selectivity of the catalyst while maintaining its activity. Summary of the invention

[0019] The present invention relates to a process for preparing a bifunctional catalyst comprising an acid function consisting of IZM-2 zeolite, a hydrogenating function comprising at least one noble metal from group VIII of the periodic table, selected from platinum and palladium, and a matrix, said process comprising at least the following steps:

[0020] i) a step of preparing the catalyst support by shaping the IZM-2 zeolite with a matrix such that the weight percentage of the zeolite is advantageously between 1 and 50% relative to the weight of the support,

[0021] ii) a step of depositing at least one noble metal from group VIII of the periodic table by impregnating the support prepared in step i) allowing the obtaining of a solid, with an aqueous solution comprising at least the following compounds:

[0022] - at least one ammonia compound selected from the platinum (II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3)2 or Pt(NH3)4X2, platinum(IV) hexamine salts of formula Pt(NH3)6X4; platinum(IV) halogenopentamine salts of formula (PtX(NH3)5)X3; platinum N-tetrahalogenodiamine salts of formula PtX4(NH3)2; and halogenated compounds of formula H(Pt(acac)2X); palladium(II) salts Pd(NH3)4SO4 or Pd(NH3)4X2, in which X is a halogen selected from chlorine, fluorine, bromine and iodine, X being preferably chlorine, and "acac" represents the acetylacetonate group (of molecular formula C5H7O2), a compound derived from acetylacetone,

[0023] iii) at least one heat treatment step in which the solid prepared in step ii) is brought into contact with at least one gaseous mixture containing oxygen, water, chlorine and / or at least one chlorinated compound, said heat treatment step being carried out at a temperature between 200 and 1100°C.

[0024] An advantage of the present invention is to provide a process for preparing a bifunctional catalyst comprising an acid phase based on IZM-2 zeolite and a hydrogenating function based on noble metals of group VIII, which, through the performance of the heat treatment of step iii), makes it possible to improve the selectivity in isomerization of the long paraffins of the catalyst, the activity of said catalyst being at least maintained.

[0025] Without wishing to be bound by any theory, the applicant believes that the improvement in the selectivity in isomerization of the long paraffins of the catalyst and the maintenance of its activity are obtained through the combination of the steps implemented in the process according to the invention, and in particular steps ii) and iii). The systematic improvement in the maximum isomerization yield observed appears to be linked to a decrease in the hydrogenolysis activity of said catalysts according to the invention.

[0026] Another advantage of the present invention is to provide a process for isomerizing paraffinic fillers from hydrotreated vegetable and / or animal oils or from low-temperature Fischer-Tropsch synthesis using said bifunctional catalyst thus obtained, allowing better selectivity in middle distillates through the implementation of the heat treatment of step iii), the activity of said catalyst being at least maintained. Detailed description of the invention

[0027] According to the invention, the present invention relates to a process for preparing a bifunctional catalyst comprising an acid function consisting of IZM-2 zeolite, a hydrogenating function comprising at least one noble metal from group VIII of the periodic table chosen from platinum and palladium alone or in mixture and a matrix. The catalyst

[0028] The catalyst prepared according to the invention comprises IZM-2 zeolite, which constitutes the acid function of said catalyst. IZM-2 zeolite has a crystalline structure.

[0029] IZM-2 zeolite is a crystalline microporous solid having a crystalline structure described in patent application FR 2 918 050. The process for preparing IZM-2 zeolite is also described in said application.

[0030] Said solid IZM-2 has a chemical composition, expressed on an anhydrous basis in terms of moles of oxides, defined by the following general formula: XO2 : aY2O3 : bM2 / nO, in which X represents at least one tetravalent element, Y represents at least one trivalent element, and M is at least one alkali metal and / or a alkaline earth metal of valence n.

[0031] X is preferably chosen from silicon, germanium, titanium, and mixtures of at least two of these tetravalent elements. Most preferably, X is silicon, and Y is preferably chosen from aluminum, boron, iron, indium, and gallium. Most preferably, Y is aluminum. M is preferably chosen from lithium, sodium, potassium, calcium, magnesium, and mixtures of at least two of these metals, and most preferably, M is sodium. Preferably, X represents silicon; the crystalline solid IZM-2 according to the invention is then an entirely silicic solid when element Y is absent from the composition of said solid IZM-2. It is also advantageous to use as element X a mixture of several elements X, in particular a mixture of silicon with another element X chosen from germanium and titanium, preferably germanium.Thus, when silicon is present in a mixture with another element X, the crystalline solid IZM-2 according to the invention is then a crystalline metallosilicate exhibiting an X-ray diffraction pattern identical to that described in Table 1 when it is in its calcined form. Even more preferably, and in the presence of an element Y, where X is silicon and Y is aluminum, the crystalline solid IZM-2 according to the invention is then an aluminosilicate.

[0032] Preferably, the IZM-2 zeolite is in aluminosilicate form.

[0033] Preferably, the molar ratio of the number of silicon atoms to the number the number of aluminum Si / Al atoms is less than 200, preferably less than 150, most preferably less than 120.

[0034] The IZM-2 zeolite forming part of the catalyst support prepared according to the invention is advantageously exchanged by at least one treatment with a solution of at least one ammonium salt, so as to obtain the ammonium form of the IZM-2 zeolite which, once calcined, leads to the acid (H+) form of said IZM-2 zeolite. This exchange step can be carried out at any stage of the catalyst preparation, i.e. after the IZM-2 zeolite preparation step, after the IZM-2 zeolite shaping step with a matrix, or after the hydro-dehydrogenating metal introduction step.

[0035] Said zeolite IZM-2 entering into the composition of the catalyst support used in the process according to the invention is advantageously at least partly, preferably practically totally, in acidic form, i.e. in acidic form (H+).

[0036] According to the invention, the prepared catalyst comprises at least one matrix. Said matrix may advantageously be amorphous or crystalline.

[0037] Preferably, said matrix is ​​advantageously chosen from the group formed by alumina, silica, silica-alumina, clays, titanium oxide, boron oxide and the Zirconia, used alone or in mixtures, or aluminates may also be chosen. Preferably, alumina is used as the matrix. Preferably, said matrix contains alumina in all its forms known to those skilled in the art, such as, for example, alpha, gamma, eta, and delta aluminas. These aluminas differ in particular in their specific surface area and pore volume.

[0038] The mixture of the matrix and the shaped IZM-2 zeolite constitutes the support for the catalyst.

[0039] Step II: Preparation of the support

[0040] According to the invention, the process includes a step i) of preparing the catalyst support by shaping the IZM-2 zeolite with a matrix, so that the weight percentage of the zeolite is advantageously between 1 and 50% relative to the weight of the support, preferably between 2 and 30% and preferably between 5 and 20%.

[0041] Formatting

[0042] The catalyst support used in the process according to the invention can advantageously be shaped by any technique known to those skilled in the art. Shaping can advantageously be carried out, for example, by extrusion, pelletizing, the oil-drop coagulation method, rotary plate granulation, or any other method well known to those skilled in the art. The supports thus obtained can be in various shapes and sizes. Preferably, step i) is carried out by mixing and extrusion.

[0043] During the shaping of the support by mixing and then extrusion, said IZM-2 zeolite can be introduced during the dissolution or suspension of alumina compounds or alumina precursors such as boehmite, for example. Said IZM-2 zeolite can be, without limitation, for example in the form of a powder, ground powder, a suspension, or a suspension that has undergone a deagglomeration treatment. Thus, for example, said zeolite can advantageously be suspended, acidified or not, at a concentration adjusted to the final IZM-2 content targeted in the catalyst according to the invention. This suspension, commonly called a slip, is then mixed with the alumina compounds or alumina precursors.

[0044] Furthermore, the use of additives can advantageously be implemented to facilitate shaping and / or improve the final mechanical properties of the substrates, as is well known to those skilled in the art. Examples of additives include cellulose, carboxymethyl cellulose, carboxyethyl cellulose, tall oil, xanthan gums, surfactants, flocculating agents such as polyacrylamides, carbon black, starches, stearic acid, polyacrylic alcohol, polyvinyl alcohol, biopolymers, glucose, polyethylene glycols, etc.

[0045] Water can advantageously be added or removed to adjust the viscosity of the paste to be extruded. This step can advantageously be carried out at any stage of the mixing step.

[0046] To adjust the solids content of the extrusion paste to make it extrudable, a predominantly solid compound, preferably an oxide or a hydrate, can also be added. Preferably, an aluminum hydrate is used, and even more preferably, an aluminum hydrate. The loss on ignition of this hydrate is advantageously greater than 15%.

[0047] The extrusion of the paste from the mixing step can advantageously be carried out using any commercially available conventional tool. The paste from the mixing process is advantageously extruded through a die, for example, using a piston or a single or double screw extrusion die. The extrusion can advantageously be carried out by any method known to those skilled in the art.

[0048] The catalyst supports prepared in step i) according to the invention are generally in the form of cylindrical or multilobed extrudates such as bilobed, trilobed, or multilobed, with a straight or twisted shape, but may optionally be manufactured and used in the form of crushed powders, tablets, rings, beads, and / or wheels. Preferably, the catalyst supports according to the invention are in the form of spheres or extrudates. Advantageously, the support is in the form of extrudates with a diameter between 0.5 and 5 mm, and more particularly between 0.7 and 2.5 mm. The shapes may be cylindrical (which may or may not be hollow) and / or twisted cylindrical and / or multilobed (2, 3, 4, or 5 lobes, for example) and / or rings. The multilobed shape is advantageously preferred.

[0049] Drying

[0050] The substrate thus obtained at the end of shaping step i) can then advantageously be subjected to a drying step. This drying step is advantageously carried out by any technique known to those skilled in the art.

[0051] Preferably, drying is carried out under an airflow. Drying can also be carried out under a flow of any oxidizing, reducing, or inert gas. Preferably, drying is advantageously carried out at a temperature between 50 and 180°C, most preferably between 60 and 150°C, and most preferably between 80 and 130°C.

[0052] Calcination

[0053] Said support, possibly dried, then preferably undergoes a calcination step.

[0054] Said calcination step is advantageously carried out in the presence of molecular oxygen, for example by performing an air purge, at a temperature advantageously greater than 200°C and less than or equal to 1100°C. Said calcination step can advantageously be carried out in a flow bed, a licked bed or in a static environment. For example, the furnace used may be a rotary kiln or a vertical kiln with radially traversed layers. Preferably, the calcination step is carried out for more than one hour at 200°C and less than one hour at 1100°C. For the shaped and possibly dried substrate, calcination may advantageously be carried out in the presence of steam and / or in the presence of acidic or basic vapor. For example, calcination may be carried out under partial pressure of ammonia.

[0055] Post-calcination treatments

[0056] Post-calcination treatments may optionally be carried out in order to improve the properties of the calcined support, in particular the textural properties.

[0057] Thus, the catalyst support used in the process according to the present invention can be subjected to hydrothermal treatment in a confined atmosphere. Hydrothermal treatment in a confined atmosphere is understood to mean treatment by passing through an autoclave in the presence of water at a temperature above ambient temperature, preferably above 25°C, preferably above 30°C.

[0058] During this hydrothermal treatment, the substrate can advantageously be impregnated prior to its passage through the autoclave (autoclaving being carried out either in the vapor phase or in the liquid phase, this vapor or liquid phase of the autoclave being able to be acidic or non-acidic). This impregnation, prior to autoclaving, can advantageously be acidic or non-acidic. This impregnation, prior to autoclaving, can advantageously be carried out dry or by immersing the substrate in an acidic aqueous solution. By dry impregnation, we mean bringing the substrate into contact with a volume of solution less than or equal to the total porous volume of the substrate. Preferably, the impregnation is carried out dry. The autoclave is preferably a rotary basket autoclave such as that defined in patent application EP 0 387 109 A. The temperature during autoclaving can be between 100 and 250°C for a period of time between 30 minutes and 3 hours.

[0059] Step ii): Deposition of the hydro-dehydrogenating function

[0060] According to the invention, the deposition of the hydro-dehydrogenating function takes place after the shaping step i).

[0061] According to the invention, the process comprises a step ii) of depositing at least one noble metal from group VIII of the periodic table by impregnating the support prepared in step i) allowing the obtaining of a solid, and having optionally undergone a drying and / or calcination and / or post-calcination treatment step, with an aqueous solution comprising at least the following compounds:

[0062] - at least one ammonia compound selected from the platinum (II) tetramine salts of the formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3)2 or Pt(NH3)4X2, the platinum(IV) hexamine salts of the formula Pt(NH3)6X4; the platinum(IV) halogenopentamine salts of formula (PtX(NH3)5)X3; platinum N-tetrahalogenodiamine salts of formula PtX4 (NH3)2; and halogenated compounds of formula H(Pt(acac)2X); palladium (II) salts Pd(NH3)4SO4 or Pd(NH3)4X2, in which X is a halogen chosen from chlorine, fluorine, bromine and iodine, X being preferably chlorine, and "acac" represents the acetylacetonate group (of empirical formula C5H7O2), a compound derived from acetylacetone.

[0063] The hydro-dehydrogenating function can advantageously be introduced before or after the calcination of the support and preferably after.

[0064] According to the invention, the substrate is impregnated with an aqueous solution. Impregnation of the substrate is preferably carried out by the so-called "dry" or "nascent moisture" impregnation method, or by impregnation with an excess of a solution, methods well known to those skilled in the art. Advantageously, impregnation can be carried out in a single step with a solution containing all the constituent elements of the final catalyst. Preferably, the so-called "dry" or "nascent moisture" impregnation method is used.

[0065] The implementation of step ii) by impregnating the support with an aqueous solution comprising the ammoniacal salts of specific metals as claimed allows the obtaining of a bifunctional catalyst comprising an acidic phase based on IZM-2 zeolite and a hydrogenating function based on noble metals of group VIII in which the group VIII metal is located on the external surface of the IZM-2 zeolite crystals and / or in the microporosity of the IZM-2 zeolite, i.e. in the IZM-2 zeolite crystals.

[0066] According to the invention, the bifunctional catalyst prepared according to the invention comprises at least one noble metal from group VIII chosen from platinum and palladium, alone or in mixture and platinum is most preferably chosen.

[0067] Preferably, step ii) consists of depositing at least one noble metal, preferably platinum, by impregnating the support prepared in step i) with an aqueous solution comprising ammonia compounds selected from platinum (II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3), or Pt(NH3)4X2, platinum (IV) hexamine salts of formula Pt(NH3)6X4; platinum (IV) halogen-pentamine salts of formula (PtX(NH3)5)X3; platinum N-tetrahalogenodiamine salts of formula PtX4(NH3)2; and halogenated compounds of formula H(Pt(acac)2X); X and "acac" having the aforementioned meaning, and preferably among the platinum (II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3), or Pt(NH3)4X2.

[0068] Preferably, said step ii) is carried out so as to deposit on said support a content of noble metal, and preferably platinum, of between 0.01 and 4%, and preferably between 0.05 and 2%, and even more preferably between 0.05 and 1% by weight relative to the total mass of said catalyst.

[0069] Preferably, the impregnation solution may also contain at least one salt ammonium not containing noble metals, selected from ammonium nitrate NH4NO3, ammonium chloride NH4C1, ammonium sulfate (NH4)2SO4, ammonium hydroxide NH4OH, ammonium bicarbonate NH4HCO3, ammonium acetate NH4H3C2O2 alone or in mixture and preferably from ammonium nitrate NH4NO3, ammonium chloride NH4C1 and ammonium acetate NH4H3C2O2 alone or in mixture.

[0070] In the case where the impregnation solution also includes an ammonium salt not containing noble metals, the concentrations of the different species in solution are such that the molar ratio between the ammonium salt not containing noble metals and the noble metal is between 0.1 and 400, preferably between 0.2 and 200, most preferably between 0.3 and 150.

[0071] The platinum concentrations in the impregnation solution are adjusted to obtain the desired noble metal content in the final catalyst.

[0072] The Castaing microprobe allows verification of whether an element, in this case platinum, is homogeneously distributed within the catalyst, by calculating a distribution coefficient (see L. Sorbier, Determining the Distribution of Metal by Electron Probe Micro Analysis, in: H. Toulhoat, P. Raybaud (Eds.), Catalysis by Transition Metal Sulphides, Ed. Technip, Paris, 2013, pp. 407-411 and references cited). The macroscopic distribution coefficient of platinum, obtained from its profile determined by the Castaing microprobe, defined as the ratio of platinum concentrations at the core of the extrudate to those at the edge of the extrudate, is between 0.7 and 1.3, preferably between 0.8 and 1.2. A value close to 1 indicates the homogeneity of the platinum distribution within the catalyst.

[0073] The preferential localization of the Group VIII noble metal within the crystals and / or on the external surface of the IZM-2 zeolite crystals can also be demonstrated by Castaing microprobe. A few extrudates are coated with resin (Struers, Ballerup), then polished and carbon-metallized. The sample is then introduced into a JEOL JXA8100 instrument to analyze the local silicon, aluminum, and platinum composition at various points. From the local aluminum and silicon composition, and knowing the silicon composition of the zeolite, the mass ratio Alumina / (IZM-2 + alumina) can be deduced for each analyzed point. The evolution of the local platinum composition as a function of the local mass ratio Alumina / (IZM-2 + alumina) can thus be plotted, and the preferential localization of platinum on the alumina or on the zeolite can be verified.When the local platinum composition increases with the local mass ratio Alumina / (IZM-2 + alumina), then platinum is preferentially localized on alumina. When the local platinum composition decreases with the local mass ratio Alumina / (IZM-2 + alumina), then platinum is preferentially localized on zeolite.

[0074] The dispersion of the noble metal(s) of group VIII, determined by chemisorption, for example by H2 / O2 titration or by chemisorption of carbon monoxide, is between 10% and 100%, preferably between 20% and 100% and even more preferably between 30% and 100%.

[0075] In one embodiment, the aqueous solution of step ii) or a different aqueous solution from that of step ii) may also include precursors of metals from groups IIIA, IVA and VIIB of the periodic table of elements, preferably selected from gallium, indium, tin and rhenium. Any precursors of such metals may be suitable.

[0076] In the case where a solution different from that of step ii) is used, the deposits of the different elements are carried out successively.

[0077] According to one variant, said precursors of said metals can be impregnated on the support from step i) separately from the precursors of the noble metals of group VIII.

[0078] When at least one metal from groups IIIA, IVA and VIIB is added separately, it is preferable that it be added after the group VIII metal. In this case, an optional second step of impregnation with at least one aqueous solution comprising the precursors of the group IIIA, IVA and VIIB metals can advantageously be carried out after step ii).

[0079] The additional metal selected from the metals of groups IIIA, IVA, and VIIB can be introduced via an aqueous solution comprising compounds selected from the chlorides, bromides, and nitrates of the metals of groups IIIA, IVA, and VIIB. For example, in the case of indium, the nitrate or chloride is advantageously used, and in the case of rhenium, perrhenic acid is advantageously used. The additional metal selected from the metals of groups IIIA, IVA, and VIIB can also be introduced via a solution comprising at least one organic compound selected from the group consisting of the complexes of said metal, and preferably the polyketone complexes of the metal and the hydrocarbyl metals selected from the alkyls, cycloalkyls, aryls, alkylaryls, and arylalkyls of metals.In the latter case, the introduction of the metal is advantageously carried out using a solution of the organometallic compound of said metal in an organic solvent. Organohalogen compounds of the metal can also be used. Examples of organic metal compounds include tetrabutyltin, in the case of tin, and triphenylindium, in the case of indium.

[0080] If the additional metal chosen from the metals of groups IIIA, IVA and VIIB is introduced before the group VIII metal, the compound of metal IIIA, IVA and / or VIIB used is generally chosen from the group consisting of the halide, nitrate, The acetate, tartrate, carbonate, and oxalate of the metal are used. The introduction is then advantageously carried out in an aqueous solution containing these compounds. However, it can also be introduced using a solution of an organometallic compound of the metal, for example, tetrabutyltin. In this case, before introducing at least one metal from Group VIII, calcination under air is performed.

[0081] In the case where several successive impregnation steps are carried out, intermediate drying and / or calcination steps and / or reduction can advantageously be implemented between the successive impregnation steps of the different metals.

[0082] Preferably, the deposit(s) are made so as to deposit on said support a content of metals of groups IIIA, IVA and VIIB of between 0.01 to 2%, and preferably between 0.05 to 1% weight relative to the total mass of said catalyst.

[0083] At least one drying step can advantageously be implemented after the impregnation step(s), and preferably after step ii). Said drying step is advantageously carried out by any technique known to a person skilled in the art.

[0084] Preferably, drying is carried out under an airflow. Drying can also be carried out under a flow of any oxidizing, reducing, or inert gas. Preferably, drying is advantageously carried out at a temperature between 50 and 180°C, most preferably between 60 and 150°C, and most preferably between 80 and 130°C.

[0085] Step iii): Heat treatment of the solid obtained from ii)

[0086] According to the invention, said process includes at least one heat treatment step iii) in which the solid from step ii) is brought into contact with at least one gaseous mixture containing oxygen, water, chlorine and / or at least one chlorinated compound, said heat treatment step being carried out at a temperature between 200 and 1100°C.

[0087] According to the invention, at least one heat treatment step of the solid obtained in step ii) is carried out after step ii), and preferably after at least one drying step.

[0088] According to the invention, said heat treatment is carried out by bringing the solid from step ii) into contact with a gas containing molecular oxygen, water and chlorine and / or at least one chlorinated compound, at a temperature above 200°C and less than or equal to 1100°C, preferably above 250°C and less than 800°C, even more preferably above 300°C and less than 700°C, most preferably above 400°C and less than 600°C.

[0089] The weight content of oxygen in the gas during the heat treatment of step iii) is preferably between 10 and 50% by weight, and preferably between 15 and 35% by weight.

[0090] The water content by weight in the gas during the heat treatment of step iii) is preferably between 0.02 and 10% by weight and preferably between 0.02 and 5% by weight.

[0091] The weight content of chlorine and / or chlorinated compound in the gas during the heat treatment of step iii) is preferably between 0.02 and 5% weight and preferably between 0.1 and 3% weight.

[0092] The chlorinated compound may be a mineral or organic chlorinated compound. The mineral chlorinated compound is preferably hydrochloric acid (HCl). The organic chlorinated compound is preferably chosen from among the chloroalkanes and most preferably from among carbon tetrachloride, dichloropropane, dichloroethane and chloroform.

[0093] Preferably, the process may advantageously include, between step ii) and heat treatment step iii), a step in which the solid from step ii) is brought into contact with a gas containing oxygen but free of chlorine and / or at least one chlorinated compound.

[0094] In this case, the solid from step ii) is brought into contact with said gas containing oxygen but free of chlorine and / or at least one chlorinated compound until it reaches the temperature desired for the implementation of step iii), i.e. for the injection of water and chlorine and / or at least one chlorinated compound.

[0095] This injection temperature of water and chlorine and / or at least one chlorinated compound is preferably greater than 200°C and less than or equal to 1100°C, preferably greater than 250°C and less than 800°C, even more preferably greater than 300°C and less than 700°C, most preferably greater than 400°C and less than 600°C.

[0096] According to a first embodiment, at least one temperature step can be implemented to reach the implementation temperature of the heat treatment step iii).

[0097] According to a second embodiment, no temperature step is implemented to reach the implementation temperature of the heat treatment step iii).

[0098] According to the invention, step iii) of heat treatment is carried out in the presence of water. Preferably the water is introduced either with the gas containing oxygen but free of chlorine or chlorinated compounds, or at the time of the introduction of the chlorine and / or chlorinated compounds.

[0099] Preferably the water is introduced at the time of the introduction of the chlorine and / or the chlorinated compound.

[0100] Said heat treatment step iii) can advantageously be carried out in a flow bed, a licked bed, or in a static atmosphere. For example, the furnace used can be a rotary kiln or a vertical radial flow bed kiln.

[0101] The temperature reduction can then advantageously be carried out under a gaseous mixture comprising oxygen, optionally water vapor, and free of chlorine. The solid is advantageously cooled in contact with said gaseous mixture, preferably from a temperature less than or equal to 400°C.

[0102] In a first preferred embodiment of the process, the solid from step ii) is first brought into contact, at ambient temperature, with a first gaseous mixture containing oxygen, the oxygen content in the gas being 10 to 50 wt%, and preferably 15 to 35 wt%. This gaseous mixture is free of chlorine and / or chlorinated compounds and its water content is less than 4 wt%. Heating in contact with the gaseous mixture is generally carried out gradually until the desired temperature plateau is reached. Typically, the temperature ramp is between 1 and 10°C per minute. Several plateaus at different temperatures can be implemented when the first gaseous mixture is used before reaching the implementation temperature of heat treatment step iii).During said step iii) the solid is brought into contact with a second gas mixture containing oxygen, chlorine and / or at least one chlorinated compound and water. The second gas mixture advantageously consists of the first gas mixture into which water and chlorine and / or at least one chlorinated compound are continuously injected.

[0103] This temperature is preferably between 400°C and 600°C, and the duration of this holding period is preferably between 1 and 10 hours. The water content by weight in the second gas mixture is preferably between 0.02 and 10% by weight, and even more advantageously between 0.02 and 5% by weight. The amount of chlorine and / or chlorinated compounds in the second gas mixture is preferably between 0.02 and 5% by weight, and more preferably between 0.1 and 3% by weight. The oxygen content in the second gas mixture is preferably between 10 and 50% by weight. Once the holding period in contact with the second gas mixture is over, the solid is then cooled in contact with said second gas mixture, preferably to a temperature less than or equal to 400°C. The solid is then cooled by contact with a third gaseous mixture free of chlorine, and containing oxygen and possibly water vapor, preferably dry air, until it reaches room temperature.The third gas mixture preferably consists of the first gas mixture in which the continuous injection of water and chlorine and / or at least one chlorinated compound is eliminated.

[0104] In a second preferred embodiment of said process, the solid obtained from step ii) is first brought into contact, at room temperature, with a first gaseous mixture containing oxygen, the oxygen content in the gas being 10 to 50 wt%, and preferably 15 to 35 wt%. Said gaseous mixture is free of chlorine and chlorinated compounds, and its water content by weight is less than 4%. Heating in contact with the gas mixture is generally carried out gradually until the target temperature is reached. Unlike the first embodiment, no temperature plateau is used when the first gas mixture is used to reach the implementation temperature of heat treatment step iii). Preferably, the temperature ramp is between 1 and 10°C per minute. The target temperature is preferably between 400°C and 600°C. Once the desired temperature is reached, the solid is brought into contact with a second gas mixture containing oxygen, chlorine and / or a chlorinated compound, and water. The second gas mixture preferably consists of the first gas mixture into which water and chlorine and / or at least one chlorinated compound are continuously injected.

[0105] This temperature is preferably between 400°C and 600°C, and the duration of this holding period is preferably between one and ten hours. The water content by weight in the second gas mixture is preferably between 0.02 and 10% by weight, and even more advantageously between 0.02 and 5% by weight. The chlorine and / or chlorinated compound content by weight in the second gas mixture is preferably between 0.02 and 5% by weight, and more preferably between 0.1 and 3% by weight. The oxygen content by weight in the second gas mixture is preferably between 10 and 50% by weight. Once the holding period in contact with the second gas mixture is over, the solid is cooled in contact with said second gas mixture, preferably to a temperature of 400°C or less.The solid is then cooled by contact with a third gas mixture free of chlorine, and containing oxygen and optionally water vapor, preferably dry air, to ambient temperature. The third gas mixture is preferably the first gas mixture in which the continuous injection of water and chlorine and / or at least one chlorinated compound is eliminated.

[0106] Before its use in the isomerization process according to the invention, the catalyst obtained at the end of the preparation process according to the invention is preferably subjected to a reduction step. This reduction step is advantageously carried out by treatment under hydrogen at a temperature between 150°C and 650°C and a total pressure between 0.1 and 25 MPa. For example, a reduction consists of a two-hour hold at 150°C followed by a temperature increase to 450°C at a rate of 1°C / min and then a two-hour hold at 450°C; throughout this reduction step, the hydrogen flow rate is 1000 normal m³ of hydrogen per ton of catalyst and the total pressure is maintained constant at 0.2 MPa. Any ex-situ reduction method can advantageously be considered. A preliminary ex-situ reduction of the final catalyst, under a stream of hydrogen, can be implemented, for example, at a temperature of 450°C to 600°C, for a duration of 0.5 to 4 hours.

[0107] Said catalyst also advantageously comprises sulfur. If the catalyst of the invention contains sulfur, the sulfur may be introduced at any stage of catalyst preparation or by in situ and / or ex situ sulfurization before the catalytic reaction. In the case of in situ sulfurization, reduction, if the catalyst has not been previously reduced, occurs before sulfurization. In the case of ex situ sulfurization, reduction is also carried out followed by sulfurization. Sulfurization is preferably carried out in the presence of hydrogen using any sulfurizing agent well known to those skilled in the art, such as, for example, dimethyl sulfide or hydrogen sulfide.

[0108] The catalysts according to the invention are available in various shapes and sizes. They are generally used in the form of cylindrical and / or multilobed extrudates such as bilobed, trilobed, or multilobed, with a straight and / or twisted shape, but may also be manufactured and used in the form of crushed powders, tablets, rings, beads, and / or wheels. Preferably, the catalysts used in the process according to the invention are in the form of spheres or extrudates. Advantageously, the catalyst is in the form of extrudates with a diameter between 0.5 and 5 mm, and more particularly between 0.7 and 2.5 mm. The shapes may be cylindrical (which may or may not be hollow) and / or twisted cylindrical and / or multilobed (2, 3, 4, or 5 lobes, for example) and / or rings. The multilobed shape is advantageously preferred. The metal deposit does not change the shape of the substrate.

[0109] The preparation process according to the invention therefore allows obtaining a bifunctional catalyst comprising an acid phase based on IZM-2 zeolite and a hydrogenating function based on noble metals of group VIII.

[0110] Another object of the invention relates to the catalyst comprising an acid function made up of IZM-2 zeolite, a hydrogenating function comprising at least one noble metal from group VIII of the periodic table chosen from platinum and palladium and a matrix, obtained by the process according to the invention.

[0111] In the catalyst obtained according to the process of the invention, the group VIII metal is preferentially located in the crystals and / or on the surface of the crystals of the IZM-2 zeolite and the group VIII metal is distributed homogeneously on said catalyst.

[0112] Said catalyst prepared according to the invention may advantageously comprise at least one additional metal selected from the group formed by the metals of groups IIIA, IVA and VIIB of the periodic table of elements and preferably selected from gallium, indium, tin and rhenium. Said additional metal is preferably selected from indium, tin and rhenium.

[0113] Said catalyst also advantageously comprises sulfur.

[0114] Said catalyst prepared according to the invention comprises more particularly, and preferably consists of:

[0115] - from 1 to 50% by weight, preferably from 2 to 30% by weight and even more preferred at 5 to 20% by weight of the IZM-2 zeolite according to the invention,

[0116] - from 0.01 to 4%, preferably from 0.05 to 2% by weight and even more preferably between 0.05 and 1% by weight relative to the total mass of said catalyst of at least one metal from group VIII of the periodic table of elements, preferably platinum,

[0117] - possibly from 0.01 to 2%, preferably from 0.05 to 1% by weight of at least one additional metal chosen from the group formed by the metals of groups IIIA, IVA and VIIB,

[0118] - possibly a sulfur content, preferably such that the ratio of the number of moles of sulfur out of the number of moles of metal(s) of group VIII is between 0.3 and 20,

[0119] - at least one matrix, preferably alumina, ensuring 100% complement in the catalyst. The isomerization process

[0120] The present invention also relates to a method for isomerizing a paraffinic feed, said method comprising bringing said paraffinic feed into contact with at least said catalyst according to the invention present in a catalytic reactor.

[0121] In accordance with the invention, said paraffin filler used in the process according to the invention is produced from renewable resources.

[0122] The paraffins in said paraffinic filler have a number of carbon atoms between 9 and 25, preferably between 10 and 25, and most preferably between 10 and 22. The paraffin content in said filler used in the process according to the invention is advantageously greater than 90% by weight, preferably greater than 95% by weight, and even more preferably greater than 98% by weight. Within said paraffins, the mass percentage of isoparaffins is less than 15%, preferably less than 10%, and most preferably less than 5%.

[0123] Preferably, said paraffinic filler is produced from renewable resources selected from vegetable oils, algae or algal oils, fish oils and fats of vegetable or animal origin, or mixtures of such fillers.

[0124] Said vegetable oils may advantageously be crude or refined, wholly or partly, and derived from plants selected from rapeseed, sunflower, soybean, palm, olive, coconut, copra, castor, cotton, oils Peanut, flax, and crambe oils, as well as all oils derived, for example, from sunflower or rapeseed through genetic modification or hybridization, are permitted. These animal fats are advantageously chosen from lard and fats composed of residues from the food industry or from the catering industry. Frying oils, various animal oils such as fish oil, tallow, and lard may also be used.

[0125] The renewable resources from which the paraffinic filler used in the process according to the invention is produced essentially contain triglyceride-type chemical structures, which those skilled in the art also know as tri esters of fatty acids, as well as free fatty acids, the fatty chains of which contain a number of carbon atoms between 9 and 25.

[0126] The structure and hydrocarbon chain length of these latter is compatible with the hydrocarbons present in diesel fuel and kerosene, i.e., the middle distillate cut. A fatty acid triester is thus composed of three fatty acid chains. These fatty acid chains, in triester form or as free fatty acids, have a number of unsaturations per chain, also called the number of carbon-carbon double bonds per chain, generally between 0 and 3, but which can be higher, particularly for oils derived from algae, which generally have a number of unsaturations per chain of 5 to 6.

[0127] The molecules present in said renewable resources used in the present invention therefore have a number of unsaturations, expressed per triglyceride molecule, advantageously between 0 and 18. In these fillers, the degree of unsaturation, expressed as the number of unsaturations per hydrocarbon fatty chain, is advantageously between 0 and 6.

[0128] Renewable resources also generally contain various impurities, including heteroatoms such as nitrogen. Nitrogen content in vegetable oils is generally between approximately 1 ppm and 100 ppm by weight, depending on their nature. It can reach up to 1% by weight in certain feedstocks.

[0129] The paraffinic feedstock used in the process according to the invention is advantageously produced from renewable resources using processes known to those skilled in the art. One possible route is the catalytic transformation of said renewable resources into deoxygenated paraffinic effluent in the presence of hydrogen, and in particular, hydrotreating.

[0130] Preferably, said paraffinic feedstock is produced by hydrotreating said renewable resources. These hydrotreating processes for renewable resources are already well known and are described in numerous patents. By way of example, said paraffinic feedstock used in the process according to the invention may advantageously can be produced, preferably by hydrotreatment followed by gas / liquid separation, from said renewable resources as in patent FR 2 910 483 or in patent FR 2 950 895.

[0131] The paraffinic feedstock used in the process according to the invention can also be a paraffinic feedstock produced by a process involving a Fischer-Tropsch conversion step. In the Fischer-Tropsch process, synthesis gas (CO+H2) is catalytically transformed into oxygenated products and essentially linear hydrocarbons in gaseous, liquid, or solid form. The products obtained constitute the feedstock of the process according to the invention. Synthesis gas (CO+H2) is advantageously produced from natural gas, coal, biomass, any source of hydrocarbon compounds, or a mixture of these sources. Thus, paraffinic feedstocks obtained, according to a Fischer-Tropsch synthesis process, from synthesis gas (CO+H2) produced from renewable resources, natural gas, or coal can be used in the process according to the invention.Preferably, said paraffinic feedstock produced by Fischer-Tropsch synthesis and used in the process according to the invention comprises predominantly n-paraffins. Thus, said feedstock comprises an n-paraffin content greater than 60% by weight relative to the total mass of said feedstock. Said feedstock may also comprise a content of oxygenated products preferably less than 10% by weight, a content of unsaturated products, i.e. preferably olefinic products, preferably less than 20% by weight, and a content of isoparaffins preferably less than 10% by weight relative to the total mass of said feedstock.

[0132] Most preferably, said filler comprises an n-paraffin content exceeding 70% by weight and, even more preferably, exceeding 80% by weight relative to the total mass of said filler. The paraffins of said paraffinic filler have a number of carbon atoms between 9 and 25, preferably between 10 and 25, and most preferably between 10 and 22.

[0133] Preferably, said paraffinic filler produced by Fischer-Tropsch synthesis is free from heteroatomic impurities such as, for example, sulfur, nitrogen or metals.

[0134] Said isomerization process is generally carried out under the following operating conditions:

[0135] - a temperature of 200°C to 500°C, preferably from 210°C to 450°C, and in a manner even more preferred from 220°C to 430°C;

[0136] - a partial pressure of hydrogen of 0.3 to 5.5 MPa, preferably of 0.4 and 4.8 MPa;

[0137] - a total pressure of 0.45 to 7 MPa, preferably of 0.6 to 6 MPa; and

[0138] - a spatial feed velocity, expressed in kilograms of introduced payload per kilogram of catalyst and per hour, from 0.25 to 30 h1, preferably from 1 to 10 h1, and even more preferably from 2 to 6 h*. List of figures

[0139] [fig.l]

[0140] Fig. 1 represents the evolution of the local weight percentage of platinum as a function of the local weight %A12O3 / (weight %A12O3+weight %IZM-2) ratio obtained by Castaing microprobe for catalyst A not in accordance with the invention.

[0141] [fig.2]

[0142] Fig. 2 represents the evolution of the local weight percentage of platinum as a function of the local weight % A12O3 / (weight % A12O3 + weight % IZM-2) ratio obtained by Castaing microprobe for catalyst B according to the invention.

[0143] [fig.3]

[0144] Fig. 3 represents the evolution of the local weight percentage of platinum as a function of the local weight % A12O3 / (weight % A12O3 + weight % IZM-2) ratio obtained by Castaing microprobe for catalyst C not according to the invention.

[0145] [fig.4]

[0146] Fig. 4 represents the evolution of the local weight percentage of platinum as a function of the local weight % A12O3 / (weight % A12O3 + weight % IZM-2) ratio obtained by Castaing microprobe for catalyst D according to the invention.

[0147] [fig.5]

[0148] Fig. 5 represents the evolution of the local weight percentage of platinum as a function of the local weight % A12O3 / (weight % A12O3 + weight % IZM-2) ratio obtained by Castaing microprobe for catalyst E according to the invention.

[0149] [fig.6]

[0150] Fig. 6 represents the evolution of the local weight percentage of platinum as a function of the local weight % A12O3 / (weight % A12O3 + weight % IZM-2) ratio obtained by Castaing microprobe for the catalyst F not in accordance with the invention.

[0151] [fig.7]

[0152] Fig. 7 represents the evolution of the local weight percentage of platinum as a function of the local weight %A12O3 / (weight %A12O3+weight %IZM-2) ratio obtained by Castaing microprobe for the catalyst G not in accordance with the invention.

[0153] The following examples illustrate the invention without, however, limiting its scope. Examples

[0154] Example 1 (not in accordance with the invention): preparation of the isomerization catalyst A

[0155] Synthesis of IZM-2 zeolite

[0156] Zeolite IZM-2 was synthesized in accordance with the teaching of patent FR 2 918 050 B. A colloidal silica suspension known by the trade name Ludox HS-40, marketed by Aldrich, is incorporated into a solution composed of sodium hydroxide (Prolabo), structuring agent 1,6bis(methylpiperidinium)hexane dibromide, aluminum hydroxide (Aldrich), and deionized water. The molar composition of the mixture is as follows: 1 SiO2; 0.0042 Al2O3; 0.1666 Na2O; 0.1666 1,6bis(methylpiperidinium)hexane; 33.3333 H2O. The mixture is stirred vigorously for half an hour. After homogenization, the mixture is transferred to a PARR-type autoclave. The autoclave is heated for 5 days at 170°C with agitation by a rotary spit (30 rpm). The resulting product is filtered, washed with deionized water to achieve a neutral pH, and then dried overnight at 100°C in an oven. The solid is then placed in a muffle furnace to be calcined in order to remove the structuring agent.The calcination cycle consists of heating to 200°C, holding at this temperature for two hours, heating to 550°C followed by an eight-hour holding period at this temperature, and finally a return to room temperature. The heating is carried out at a rate of 2°C / min. The resulting solid is then refluxed for two hours in an aqueous ammonium nitrate solution (10 mL of solution per gram of solid, ammonium nitrate concentration of 3 M) to exchange the alkali sodium cations for ammonium ions. This refluxing step is performed four times with fresh ammonium nitrate solution. The solid is then filtered, washed with deionized water, and dried overnight in an oven at 100°C.Finally, to obtain the zeolite in its acidic form (protonated H+), a calcination step is carried out at 550°C for ten hours (temperature ramp of 2°C / min) in a flow-through bed under dry air (2 normal liters per hour per gram of solid). The solid thus obtained was analyzed by X-ray diffraction and identified as being composed of IZM-2 zeolite.

[0157] Preparation of the IZM-2 / alumina support (step i))

[0158] The IZM-2 / alumina support is obtained by mixing and extruding IZM-2 zeolite with an alumina gel supplied by AXENS. The mixed paste is extruded through a 1.5 mm diameter quadrilobe die. After drying overnight in an oven at 110°C, the extrudates are calcined at 520°C for two hours (temperature ramp of 5°C / min) in a flow bed under dry air (2 normal liters per hour per gram of solid). The weight content of IZM-2 zeolite on the support after calcination is 13% wt.

[0159] Platinum Deposition (step ii). (compliant)

[0160] The deposition is carried out by dry impregnation of the IZM-2 / alumina support prepared in step i) with an aqueous solution containing tetramine platinum nitrate Pt(NH3)4 (NO3)2. Typically, 20 grams of support are used, which are dry impregnated in drageoir. After impregnation, the solid is left to mature for at least five hours in laboratory air and then left to dry overnight in a ventilated oven at 110°C.

[0161] Heat treatment of the solid from ii) (step iii). (non-conforming)

[0162] After drying, the solid is then calcined in a flow bed under a flow of dry air (1 normal liter per hour per gram of solid), the weight content of oxygen in the gas being 23% wt, the first gas mixture being chlorine-free and containing a water content of less than 0.001% wt in a tubular furnace under the following conditions:

[0163] - temperature rise from ambient to 150°C at 5°C / min;

[0164] - one-hour plateau at 150°C;

[0165] - rise from 150 to 450°C at 5°C / min;

[0166] - one-hour plateau at 450°C;

[0167] - descent to ambient temperature.

[0168] At the end of step iii) various characterizations are carried out on catalyst A. The Pt content measured by FX is 0.34% by weight, its distribution coefficient measured by Castaing microprobe is 1.03.

[0169] Figure 1 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. Locally, the weight percentage of platinum decreases with increasing alumina relative to IZM-2, indicating preferential platinum deposition on IZM-2 zeolite. Thus, for weight percentages of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) approaching 1, i.e., for analyzed areas not containing IZM-2 zeolite, the weight percentage of platinum tends towards zero.

[0170] Example 2 (according to the invention): preparation of the isomerization catalyst B

[0171] Synthesis of zeolite IZM-2

[0172] This is the same zeolite as that described in Example 1.

[0173] Preparation of the IZM-2 / alumina support (step i))

[0174] This is the same support as that described in example 1.

[0175] Platinum Deposition (step ii). (compliant)

[0176] This is the same repository as that described in example 1.

[0177] Heat treatment of the solid obtained from ii) (step iii). conforming)

[0178] After drying, the catalyst then undergoes heat treatment by contacting, at ambient temperature, in a tubular furnace, said catalyst with a first gaseous mixture consisting of dry air, the weight content of oxygen in the gas being 23% wt, the first gaseous mixture being free of chlorine and containing a water content of less than 0.001% wt under the following conditions:

[0179] - temperature rise from ambient to 150°C at 5°C / min under dry air flow (1 normal litre per hour and per gram of solid);

[0180] - one-hour plateau at 150°C under dry air flow (1 normal liter per hour and per gram of solid);

[0181] - rise from 150 to 450°C at 5°C / min under dry air flow (1 normal liter per hour and per gram of solid);

[0182] - one-hour plateau at 450°C under dry air flow (1 normal liter per hour and per gram of solid);

[0183] - rise from 450°C to 520°C at 5°C / min under dry air flow (3.3 normal liters per hour and per gram of solid).

[0184] At the beginning of the 520°C holding period, water and dichloropropane are continuously injected into the first gas mixture to form the second gas mixture. The injected quantities correspond to a water content of 2% by weight and a dichloropropane content of 0.63% by weight in the gas mixture. The temperature holding period at 520°C is maintained for four hours. The temperature is then reduced from 520°C to 400°C at 5°C / min, still under the second gas mixture. At 400°C, the injection of water and dichloropropane is stopped and the solid is cooled to ambient temperature under a flow of dry air (3.3 normal liters per hour per gram of solid).

[0185] At the end of step iii) various characterizations are carried out on catalyst B. The Pt content measured by FX is 0.34% by weight, its distribution coefficient measured by Castaing microprobe is 1.03.

[0186] Figure 2 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. As with catalyst A, it is noted that locally the weight percentage of Pt decreases with increasing alumina relative to IZM-2, indicating preferential platinum deposition on the IZM-2 zeolite.

[0187] Example 3 (not in accordance with the invention): preparation of the isomerization catalyst C

[0188] Synthesis of IZM-2 zeolite

[0189] This is the same zeolite as that described in Example 1.

[0190] Preparation of the IZM-2 / alumina support (step i))

[0191] The IZM-2 / alumina support is obtained by mixing and extruding IZM-2 zeolite with an alumina gel supplied by AXENS. The mixed paste is extruded through a 1.5 mm diameter quadrilobe die. After drying overnight in an oven at 110°C, the extrudates are calcined at 550°C for two hours (temperature ramp of 5°C / min) in a flow bed under dry air (2 normal liters per hour per gram of solid). The weight content of IZM-2 zeolite on the support after calcination is 13% wt.

[0192] Platinum Deposition (step ii). (compliant)

[0193] The deposition is carried out by dry impregnation of the IZM-2 / alumina support prepared in step i) with an aqueous solution containing tetramine platinum nitrate Pt(NH3)4 (NO3)2. Typically, 20 grams of support are used, which are dry-impregnated in a dripping tray. After impregnation, the solid is allowed to mature for at least five hours in laboratory air and then dried overnight in a ventilated oven at 110°C.

[0194] Heat treatment of the solid from ii) (step iii). (non-conforming)

[0195] After drying, the solid is then calcined in a flow bed under a flow of dry air (1 normal liter per hour per gram of solid), the weight content of oxygen in the gas being 23% wt, said dry air being free of chlorine and containing a water content of less than 0.001% wt in a tubular furnace under the following conditions:

[0196] - temperature rise from ambient to 150°C at 5°C / min;

[0197] - one-hour plateau at 150°C;

[0198] - rise from 150 to 450°C at 5°C / min;

[0199] - one-hour plateau at 450°C;

[0200] - descent to ambient temperature.

[0201] At the end of step iii) various characterizations are carried out on the catalyst C. The Pt content measured by FX is 0.26% by weight, its distribution coefficient measured by Castaing microprobe is 1.00.

[0202] Figure 3 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. Locally, the weight percentage of platinum decreases with increasing alumina relative to IZM-2, indicating preferential platinum deposition on IZM-2 zeolite. Thus, for weight percentages of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) approaching 1, i.e., for analyzed areas not containing IZM-2 zeolite, the weight percentage of platinum tends towards zero.

[0203] Example 4 (according to the invention): preparation of the isomerization catalyst D

[0204] Synthesis of IZM-2 zeolite

[0205] This is the same zeolite as that described in Example 1.

[0206] Preparation of the IZM-2 / alumina support (step i))

[0207] This is the same support as that described in example 3.

[0208] Platinum Deposition (step ii). (compliant)

[0209] This is the same repository as that described in example 3.

[0210] Heat treatment of the solid obtained from ii) (step iii). conforming)

[0211] After drying, the catalyst then undergoes heat treatment by contacting, at ambient temperature in a tubular furnace, said catalyst with a first gaseous mixture of dry air, the oxygen content in the gas being 23% by weight, the first gaseous mixture being chlorine-free and containing a content in water content less than 0.001% by weight under the following conditions:

[0212] - temperature rise from ambient to 150°C at 5°C / min under dry air flow (1 normal litre per hour and per gram of solid);

[0213] - one-hour plateau at 150°C under dry air flow (1 normal liter per hour and per gram of solid);

[0214] - rise from 150 to 450°C at 5°C / min under dry air flow (1 normal liter per hour and per gram of solid);

[0215] - one-hour plateau at 450°C under dry air flow (1 normal liter per hour and per gram of solid);

[0216] - rise from 450°C to 520°C at 5°C / min under dry air flow (3.3 normal liters per hour and per gram of solid).

[0217] At the beginning of the 520°C holding period, water and dichloropropane are continuously injected into the first gas mixture to form the second gas mixture. The injected quantities correspond to a water content of 2% by weight and a dichloropropane content of 0.63% by weight in the gas mixture. The temperature holding period at 520°C is maintained for four hours. The temperature is then reduced from 520°C to 400°C at 5°C / min, still under the second gas mixture. At 400°C, the injection of water and dichloropropane is stopped and the solid is cooled to room temperature under a flow of dry air (3.3 normal liters per hour per gram of solid).

[0218] At the end of step iii) various characterizations are carried out on the catalyst D. The Pt content measured by FX is 0.25% by weight, its distribution coefficient measured by Castaing microprobe is 0.99.

[0219] Figure 4 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. As with catalyst A, it is noted that locally the weight percentage of Pt decreases with increasing alumina relative to IZM-2, indicating preferential platinum deposition on the IZM-2 zeolite. Thus, for weight percentages of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) approaching 1, i.e., for analyzed areas not containing IZM-2 zeolite, the weight percentage of platinum tends towards zero.

[0220] Example 5 (according to the invention): preparation of the isomerization catalyst E

[0221] Synthesis of zeolite IZM-2

[0222] This is the same zeolite as that described in Example 1.

[0223] Preparation of the IZM-2 / alumina support (step i))

[0224] This is the same support as that described in example 3.

[0225] Platinum Deposition (step ii). (compliant)

[0226] This is the same repository as that described in example 3.

[0227] Heat treatment of the solid obtained from ii) (step iii). conforming)

[0228] After drying, the catalyst then undergoes heat treatment by contacting it at ambient temperature, in a tubular furnace, with a first gaseous mixture of dry air (3.3 normal liters per hour per gram of solid), the oxygen content in the gas being 23 wt%, the first gaseous mixture being chlorine-free and containing a water content of less than 0.001 wt%. The temperature is raised from ambient to 520°C at 5°C / min.

[0229] At the beginning of the 520°C holding period, in addition to the flow rate of the first dry air gas mixture, water and dichloropropane are continuously injected to form a second gas mixture. The injected quantities correspond to a water content of 2% by weight and a dichloropropane content of 0.63% by weight in the gaseous effluent. The 520°C holding period is maintained for four hours. The temperature is then reduced from 520°C to 400°C at 5°C / min, still under the second gas mixture. At 400°C, the injection of water and dichloropropane is stopped, and the solid is cooled to ambient temperature under a dry air flow rate (3.3 normal liters per hour per gram of solid).

[0230] At the end of step iii) various characterizations are carried out on the catalyst E. The Pt content measured by FX is 0.25% by weight, its distribution coefficient measured by Castaing microprobe is 1.00.

[0231] Figure 5 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. As with catalyst A, it is noted that locally the weight percentage of Pt decreases with increasing alumina relative to IZM-2, indicating preferential platinum deposition on the IZM-2 zeolite. Thus, for weight percentages of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) approaching 1, i.e., for analyzed areas not containing IZM-2 zeolite, the weight percentage of platinum tends towards zero.

[0232] Example 6 (not in accordance with the invention): preparation of the isomerization catalyst F

[0233] Synthesis of IZM-2 zeolite

[0234] This is the same zeolite as that described in Example 1.

[0235] Preparation of the IZM-2 / alumina support (step i))

[0236] This is the same support as that described in example 3.

[0237] Platinum Deposition (step ii). (non-compliant)

[0238] Catalyst F is prepared by excessively impregnating the IZM-2 / alumina support with an aqueous solution containing hexachloroplatinic acid, a platinum precursor not according to the invention. The concentration of hexachloroplatinic acid in the solution is 1.28 x 10³ mol / L.

[0239] 20 grams of support are used, the porous volume of which is filled with distilled water, and the solid is left to mature for one hour at room temperature. The solid is then immersed in 80 mL of a 3.52 x 10⁻¹ mol hydrochloric acid (HCl) solution in an Erlenmeyer flask. The flask is then stirred on a mixing table (100 rpm) at room temperature for one hour. The hydrochloric acid solution is then withdrawn, and the solid is immersed in 80 mL of the previously described hexachloroplatinic acid solution. The flask is then stirred on a mixing table (100 rpm) at room temperature for 24 hours. The impregnation solution is then withdrawn, and the solid is rinsed with 160 mL of distilled water. The solid is then dried overnight in a ventilated oven at 110°C.

[0240] Heat treatment of the solid from ii) (step iii). (non-conforming)

[0241] After drying, the solid is then calcined in a flow bed under a flow of dry air (1 normal liter per hour per gram of solid), the weight content of oxygen in the gas being 23% wt, said dry air being free of chlorine and containing a water content of less than 0.001% wt in a tubular furnace under the following conditions:

[0242] - temperature rise from ambient to 150°C at 5°C / min;

[0243] - one-hour plateau at 150°C;

[0244] - rise from 150 to 450°C at 5°C / min;

[0245] - one-hour plateau at 450°C;

[0246] - descent to ambient temperature.

[0247] At the end of step iii) various characterizations are carried out on the catalyst F. The Pt content measured by FX is 0.11% by weight, its distribution coefficient measured by Castaing microprobe is 1.01.

[0248] Figure 6 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. Unlike catalysts A, B, C, D, and E, it is noted that locally the weight percentage of Pt tends to increase with increasing alumina relative to IZM-2, indicating preferential deposition of platinum on alumina.

[0249] Example 7 (not in accordance with the invention): preparation of the isomerization catalyst G

[0250] Synthesis of IZM-2 zeolite

[0251] This is the same zeolite as that described in Example 1.

[0252] Preparation of the IZM-2 / alumina support (step i))

[0253] This is the same support as that described in example 6.

[0254] Platinum Deposition [step ii) non-compliant]

[0255] This is the same deposit as that described in Example 6 with the platinum precursor not in accordance with the invention.

[0256] Heat treatment of the solid obtained from ii) [step iii). conforming)

[0257] After drying, the catalyst then undergoes heat treatment by contacting, at ambient temperature, in a tubular furnace, said catalyst with a first gaseous mixture of dry air, the weight content of oxygen in the gas being 23% wt, the first gaseous mixture being free of chlorine and containing a water content of less than 0.001% wt under the following conditions:

[0258] - temperature rise from ambient to 150°C at 5°C / min under dry air flow (1 normal litre per hour and per gram of solid);

[0259] - one-hour plateau at 150°C under dry air flow (1 normal liter per hour and per gram of solid);

[0260] - rise from 150 to 450°C at 5°C / min under dry air flow (1 normal liter per hour and per gram of solid);

[0261] - one-hour plateau at 450°C under dry air flow (1 normal liter per hour and per gram of solid);

[0262] - rise from 450°C to 520°C at 5°C / min under dry air flow (3.3 normal liters per hour and per gram of solid).

[0263] At the beginning of the 520°C holding period, in addition to the flow rate of the first gas mixture of dry air, water and dichloropropane are continuously injected to form the second gas mixture. The injected quantities correspond to a water content of 2% by weight and a dichloropropane content of 0.63% by weight in the gaseous effluent. The temperature holding period at 520°C is maintained for four hours. The temperature is then reduced from 520°C to 400°C at 5°C / min, still under the second gas mixture. At 400°C, the injection of water and dichloropropane is stopped, and the solid is cooled to ambient temperature under a flow rate of dry air (3.3 normal liters per hour per gram of solid).

[0264] At the end of step iii) various characterizations are carried out on the catalyst G. The Pt content measured by FX is 0.10% by weight and its distribution coefficient measured by Castaing microprobe is 1.04.

[0265] Figure 7 shows the evolution of the local weight percentage of platinum as a function of the local weight percentage of A12O3 / (weight percentage of A12O3 + weight percentage of IZM-2) obtained by Castaing microprobe. Unlike catalysts A, B, C, D, and E, it is noted that locally the weight percentage of Pt tends to increase with increasing alumina relative to IZM-2, indicating preferential deposition of platinum on alumina.

[0266] Example 8: Evaluation of the catalytic properties of catalysts in isomerization of a paraffinic feedstock

[0267] The catalysts were tested by isomerization of a paraffinic feedstock composed of n-hexadecane. The tests were carried out in a micro-unit employing a fixed-bed reactor and operating in downflow without recycling. The analysis of the hydrocarbon effluents was performed online by gas chromatography. Once loaded into the unit, the catalyst undergoes an initial drying stage under nitrogen under the following conditions:

[0268] - nitrogen flow rate: 2 normal liters per hour per gram of catalyst,

[0269] - total pressure: 0.1 MPa,

[0270] - Temperature ramp from ambient to 150°C: 5°C / min,

[0271] - plateau at 150°C for 30 minutes.

[0272] After drying, nitrogen is replaced by hydrogen and a reduction step under a flow of pure hydrogen is then carried out under the following conditions:

[0273] - hydrogen flow rate: 5 normal liters per hour per gram of catalyst,

[0274] - total pressure: 1.1 MPa,

[0275] - Temperature ramp from 150 to 450°C: 5°C / min,

[0276] - plateau at 450°C for 1 hour.

[0277] After the reduction step, the temperature was lowered to 230°C, and the catalyst was brought into contact with n-hexadecane under the following conditions:

[0278] - spatial feed rate of 2 grams of n-hexadecane per hour and per gram of catalyst,

[0279] - hydrogen molar ratio to n-hexadecane of 10,

[0280] - total pressure of 1.1 MPa.

[0281] The conversion is modified by varying the temperature; and at each temperature step, two analyses of the effluent are performed, allowing the calculation of catalytic performance and verification of the stability of the catalytic performance for that temperature step. Typically, the temperature is varied between 230 and 350°C in 5°C increments. The effluent analysis is carried out entirely using an online GC system. The temperature required to achieve 50% conversion serves as a descriptor of the catalyst activity, while the maximum yield obtained of hexadecane isomers serves as a descriptor of the isomerizing properties of the catalyst. The yield of methane and ethane at 310°C is used as a descriptor of the hydrogenolytic activity of the catalyst.

[0282] Table 1 thus reports the catalytic performance of the catalysts in hydroconversion of n-hexadecane.

[0283] [Tables 1] Catalyst A (non-compliant) B (compliant) C (non-compliant) D (compliant) E (compliant) F (non-compliant) G (non-compliant) Pt Deposit Compliant Compliant Compliant Compliant Non-compliant Compliant Compliant Treatment Non-compliant Non-compliant Compliant Non-compliant Thermal treatment Compliant Compliant Compliant Temperature at 50% conversion (°C) 278 279 284 281 281 276 278 Maximum isomer yield (% by weight) 85 87 86 87 87 83 83 Methane and ethane yield at 310°C 0.09 0.03 0.09 0.03 0.02 0.02 0.02

[0284] Table 1: Catalytic performance of catalysts in hydroconversion of n-hexadecane.

[0285] Catalysts A and B are prepared from the same IZM-2 / alumina support. For both solids, the Pt deposition protocol conforms to the invention, but the heat treatment after Pt deposition on catalyst A does not. It is observed that the catalysts exhibit comparable catalytic activities (within one degree of activity difference), but that catalyst B, having undergone treatment according to the invention, exhibits a higher maximum isomerization yield. Catalyst B also exhibits lower hydrogenolysis activity than catalyst A at 310°C, as the methane and ethane yields are reduced by a factor of 3.

[0286] Catalysts C, D, and E are prepared from the same IZM-2 / alumina support. For these three solids, the Pt deposition also conforms to the invention, but the heat treatment after Pt deposition on catalyst C does not. It is observed that the conforming catalysts D and E exhibit better activity (a difference of three degrees). Both catalysts D and E also show a higher maximum isomerization yield than catalyst C. However, catalysts D and E also exhibit lower hydrogenolysis activity than catalyst C at 310°C, as the methane and ethane yields are reduced by a factor of 3 and 4.5, respectively.

[0287] Finally, catalysts F and G are prepared from the same IZM-2 / alumina support as catalysts C, D, and E. However, for these two catalysts, the Pt deposition protocol does not conform to the invention. The heat treatment of catalyst F after Pt deposition is not compliant, whereas that of catalyst G is. It is observed that, in this case, the heat treatment according to the invention does not improve the maximum isomerization yield, which is the same for both catalysts. Similarly, the methane and ethane yields remain the same for both catalysts. Finally, it is observed that the maximum isomerization yields on the non-compliant catalysts F and G are significantly lower than those obtained with the compliant catalysts D and E, which are prepared from the same IZM-2 / alumina support as catalysts F and G.

[0288] It is therefore clear that the systematic improvement of the maximum yield in isomerization is observed for catalysts according to the invention having both a preferential localization of Pt on or in the zeolite and a compliant heat treatment, and is linked to a decrease in the hydrogenolysis activity of said catalysts.

Claims

Demands

1. A process for preparing a bifunctional catalyst comprising an acid function consisting of IZM-2 zeolite, a hydrogenating function comprising at least one noble metal of Group VIII of the periodic table, selected from platinum and palladium, and a matrix, said process comprising at least the following steps: i) a step of preparing the catalyst support by shaping the IZM-2 zeolite with a matrix such that the weight percentage of the zeolite is advantageously between 1 and 50% relative to the weight of the support, ii) a step of depositing at least one noble metal of Group VIII of the periodic table by impregnating the support prepared in step i) to obtain a solid, with an aqueous solution comprising at least the following compounds: - at least one ammonia compound selected from the platinum(II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3)2 or Pt(NH3)4X2,platinum (IV) hexamine salts of formula Pt(NH3)6X4; platinum (IV) halogenopentamine salts of formula (PtX(NH3)5)X3; platinum N-tetrahalogenodiamine salts of formula PtX4(NH3)2; and halogenated compounds of formula H(Pt(acac)2X); palladium(II) salts Pd(NH3)4SO4 or Pd(NH3)4X2, wherein X is a halogen selected from chlorine, fluorine, bromine and iodine, X preferably being chlorine, and "acac" represents the acetylacetonate group (of molecular formula C5H7O2), a compound derived from acetylacetone, iii) At least one heat treatment step in which said solid prepared in step ii) is brought into contact with at least one gaseous mixture containing oxygen, water, chlorine and / or at least one chlorinated compound, said heat treatment step being carried out between 200 and 1100°C.

2. A method according to claim 1 in which step i) is carried out by mixing-extrusion.

3. A method according to any one of claims 1 or 2 wherein said matrix implemented in step i) is alumina.

4. A method according to any one of claims 1 to 3 wherein the support obtained at the end of step i) is subjected to a drying step carried out at a temperature between 50 and 180°C.

5. A method according to any one of claims 1 to 4 in which X is chlorine.

6. A process according to any one of claims 1 to 5 wherein the aqueous solution of step ii) comprises ammonia compounds selected from platinum (II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3), or Pt(NH3)4X2, platinum (IV) hexamine salts of formula Pt(NH3)6X4; platinum (IV) halogenopentamine salts of formula (PtX(NH3)5)X3; platinum N-tetrahalogenodiamine salts of formula PtX4(NH3)2; and halogenated compounds of formula H(Pt(acac)2 X); X and "acac" having the above meaning.

7. A process according to claim 6 wherein said solution comprises ammonia compounds selected from the platinum (II) tetramine salts of formula Pt(NH3)4(OH)2, Pt(NH3)4(NO3), or Pt(NH3)4X2.

8. A process according to any one of the preceding claims wherein the impregnation solution also contains at least one ammonium salt not containing noble metals, selected from ammonium nitrate NH4NO3, ammonium chloride NH4C1, ammonium sulfate (NH4)2SO4, ammonium hydroxide NH4OH, ammonium bicarbonate NH4HCO3, ammonium acetate NH4H3C2O2 alone or in mixture and preferably from ammonium nitrate NH4NO3, ammonium chloride NH4C1 and ammonium acetate NH4H3C2O2 alone or in mixture.

9. A method according to claim 8 wherein the molar ratio between the ammonium salt and the noble metal is between 0.1 and 400.

10. A method according to any one of the preceding claims wherein said heat treatment of step iii) is carried out at a temperature above 300°C and below 700°C.

11. A process according to any one of the preceding claims wherein the chlorinated compound is a mineral or organic chlorinated compound, and preferably organic, selected from carbon tetrachloride, dichloropropane, dichloroethane and chloroform.

12. A process according to any one of the preceding claims, wherein a step in which the solid from step ii) is brought into contact with a gas containing oxygen but free from chlorine and / or at least a chlorinated compound is carried out between step ii) and the heat treatment step iii), until the desired temperature for carrying out step iii is reached.

13. A method according to claim 12 wherein the implementation temperature of step iii) is greater than 300°C and less than 700°C.

14. Catalyst comprising an acid function consisting of zeolite IZM-2, a hydrogenating function comprising at least one noble metal from group VIII of the periodic table selected from platinum and palladium and a matrix, obtained by the process according to any one of claims 1 to 13.

15. A process for isomerizing a paraffinic feedstock having a number of carbon atoms between 9 and 25, said process comprising bringing said paraffinic feedstock into contact with at least said catalyst according to claim 14, said process being carried out at a temperature of 200°C to 500°C, a partial pressure of hydrogen of 0.3 to 5.5 MPa, a total pressure of 0.45 to 7 MPa, and a spatial feed rate, expressed in kilograms of feedstock introduced per kilogram of catalyst per hour, of 0.25 to 30 h1.

16. A process according to claim 15 wherein said paraffinic filler is produced from renewable resources selected from vegetable oils, algae or algal oils, fish oils and fats of vegetable or animal origin, or mixtures of such fillers.

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