FR2969641A1 - Producing middle distillates e.g. diesel from feedstock from renewable sources comprises hydrotreating the feedstock with hydrotreatment catalyst and hydroisomerization of obtained effluent with hydroisomerization catalyst - Google Patents

Abstract

Producing middle distillates from at least one feedstock from renewable sources comprises hydrotreating the feedstock with at least a hydrotreatment catalyst at a temperature of 120-450[deg] C, at a pressure of 1-10 MPa, and at a hourly space velocity of 0.1-10 hours -> 1>and in the presence of hydrogen/feedstock ratio of 50-3000 Nm 3>and hydroisomerization of obtained effluent with at least one hydroisomerization catalyst at a temperature of 120-450[deg] C, at a pressure of 1-10 MPa and at a hourly space velocity of 0.1-10 hours -> 1>and in the presence of hydrogen/feedstock ratio of 50-3000 Nm 3>. Producing middle distillates from at least one feedstock from renewable sources comprises: hydrotreating the feedstock with at least a hydrotreatment catalyst at a temperature of 120-450[deg] C, at a pressure of 1-10 MPa, and at a hourly space velocity of 0.1-10 hours -> 1>and in the presence of hydrogen/feedstock ratio of 50-3000 Nm 3>of hydrogen/m 3>of feedstock; and hydroisomerization of obtained effluent with at least one hydroisomerization catalyst at a temperature of 120-450[deg] C, at a total pressure of 1-10 MPa and at a hourly space velocity of 0.1-10 hours -> 1>and in the presence of hydrogen/feedstock ratio of 50-3000 Nm 3>of hydrogen/m 3>of feedstock, where the catalyst, comprises, in the oxide form, at least one metal from group VIB and/or at least one metal from group VIII of the periodic table, present in the form of at least one polyoxometalate of formula (H hX xM mO y)(q-), the polyoxometalate is present within an oxide based mesostructured matrix of at least one element Y1 comprising silicon, aluminum, titanium, zirconium, gallium and/or cerium, the matrix has a pore size of 1.5-50 nm and amorphous wall thickness of 1-30 nm, and the catalyst is sulfurized prior to use in the process. X : P, Si, B, Ni or Co; M : one or more element comprising Mo, W, Ni or Co; h : 0-12; x : 0-4; m : 5-12 or 18; y : 17-72; and q : 1-20.

Description

The present invention relates to the field of processes for producing middle distillates from at least one feedstock derived from renewable sources alone or mixed with petroleum hydrocarbon feedstocks. It mainly relates to the use of a specific catalyst in processes for the production of middle distillates, preferably diesel and kerosene type. STATE OF THE PRIOR ART The international context of the years 2005-2010 is marked first and foremost by the rapid growth in need of fuels, in particular diesel fuel bases in the European community and then by the importance of the problems related to global warming and the emission of greenhouse gases. The result is a desire to reduce energy dependence on fossil-based raw materials and on reducing CO2 emissions. In this context, the search for new charges from renewable sources that can be easily integrated into the traditional pattern of refining and fuel production is an issue of increasing importance. As such, the integration into the refining process of new products of plant origin, resulting from the conversion of lignocellulosic biomass or from the production of vegetable oils or animal fats, has in recent years experienced a very lively renewed interest due to the rising cost of fossil fuels. Similarly, traditional biofuels (mainly ethanol or methyl esters of vegetable oils) have acquired a real status of complement to petroleum bases in fuel pools. In addition, the processes known to date using vegetable oils or animal fats are responsible for significant emissions of CO2, known for its negative effects on the environment. A better use of these bio-resources, such as for example their integration in the fuel pool would therefore be a definite advantage.

The production of fuel bases is increasingly identified as an attractive new outlet for the agricultural world, especially for vegetable oil producers, who grind oilseeds such as rapeseed, soya beans or sunflower seeds. In fact, these vegetable oils consist of fatty acids in the form of triglycerides having long alkyl chains whose structure corresponds to the normal paraffins of the gas oil and kerosene cuts (chain length of 12 to 24 carbon atoms, depending on the nature of the vegetable oil). Inadapted to the direct feeding of modern diesel engines, these vegetable oils must be transformed beforehand.

One of the existing approaches relies on the transesterification reaction with an alcohol such as methanol leading to methyl esters of vegetable oils (VOME) commonly called biodiesel. This path is now widely used in Europe since the production of VOME has increased dramatically in the last ten years, reaching 1.5 Mt in 2003 (the average annual growth rate was 35% between 1992 and 2003). This production is supported in particular by the European directive on the promotion of biofuels (2003/30 / EC), which sets increasing targets for biofuel consumption in the transport sector. These consumptions will have to represent at least 20/0 in 2005, 5,750 / 0 in 2010 and 8% (percentages measured in energy) in 2015 of the global consumption of gasoline and diesel fuel used in transport. However, this type of process is relatively expensive and requires limiting the type of vegetable oils to meet biodiesel specifications. In addition, the charges for this type of process must be carefully selected, so that a number of vegetable oils can not be treated in this way. Finally, the cold properties of these products are also a limiting factor.

Another approach consists in directly exploiting vegetable oils via their transformation into elemental fatty acid derivatives, by means of hydrotreatment or hydroconversion processes whose catalysts are also well known to those skilled in the art for their properties. hydrodeoxygenation (E. Lawrence, Delmon B., Catal.App., 1994, 109, 1, 77 and 97). In this case, the triglycerides are converted into mainly paraffinic and saturated derivatives, thus constituting excellent hydrocarbon bases for the diesel fuel pool because of their good cetane numbers.

The main disadvantage of this type of process is the high hydrogen consumption and the cold properties of the poorly obtained hydrocarbon bases.

In general, it is accepted that a hydrotreatment catalyst with a high catalytic potential is characterized by an optimized hydro-dehydrogenating function, that is to say a fully dispersed active phase on the surface of the support and having a metal content high. Ideally, whatever the nature of the hydrocarbon feedstock to be treated, the catalyst must be able to provide an accessibility of the active sites with respect to the reagents and products of the reactions while developing a high active surface, which leads to specific constraints. in terms of structure and texture specific to the constituent oxide support of said catalysts.

The composition and use of conventional hydrotreatment catalysts for hydrocarbon feedstocks are well described in "Hydrocracking Science and Technology", 1996, J. Scherzer, AJ Gruia, Marcel Dekker Inc. and in the article by BS Clausen, HT Topsoe, FE Massoth, from "Catalysis Science and Technology", 1996, Volume 11, Springer-Verlag. Thus, these catalysts are generally characterized by the presence of an active phase based on at least one Group VIB metal and / or at least one Group VIII metal of the periodic table of the elements. The most common formulations are cobalt-molybdenum (CoMo), nickel-molybdenum (NiMo) and nickel-tungsten (NiW). These catalysts can be in mass form or in the supported state then involving a porous solid of different nature. In the latter case, the porous support is generally an amorphous or poorly crystallized oxide, such as for example an alumina, or an aluminosilicate, optionally combined with a zeolite material or not. After preparation, at least one Group VIB metal and / or at least one Group VIII metal constituent (s) of said catalysts is often in oxide form. The active and stable form of said catalysts for the hydrotreatment processes being the sulphurized form, these catalysts must undergo a sulphurization step. This can be carried out in the unit of the associated process, in which case it is known as in-situ sulphurization or prior to the loading of the catalyst into the unit, this being known as ex-situ sulphurization.

The usual methods leading to the formation of the active phase of the hydrotreatment catalysts consist in depositing the molecular precursor (s) of at least one Group VIB metal and / or at least one Group VIII metal on a oxide support by the so-called "dry impregnation" technique followed by the maturation, drying and calcination stages leading to the formation of the oxidized form of the said metal (s) employed. Then comes the final stage of sulfuration generating the active phase as mentioned above.

The catalytic performances of hydrotreatment catalysts resulting from these "conventional" synthesis protocols have been extensively studied. In particular, it has been shown that, for relatively high metal contents, sulfurization-refractory phases formed subsequent to the calcination step and due to a sintering phenomenon occur (BS Clausen, HT Topsoe, and FE Massoth , from "Catalysis Science and Technology", 1996, Volume 11, Springer-Verlag). For example, in the case of catalysts of CoMo or NiMo type supported on an aluminum support, these sulfurization-resistant phases are either crystallites of metal oxides of formula MoO 3, NiO, CoO, CoMoO 4 or CO 3 O 4, of sufficient size. to be detected in XRD, or species of type AI2 (MoO4) 3, CoAl2O4 or NiAl2O4 or both. The three species of the type AI2 (MoO4) 3, CoAl2O4 or NiAl2O4 containing the aluminum element are well known to those skilled in the art. They result from the interaction between the aluminum support and the precursor salts in solution of the active phase, which concretely results in a reaction between Al3 + ions extracted from the aluminum matrix and said salts to form Anderson heteropolyanions of formula [AI (OH) 6 Mo 6 O 18] 3 ", themselves precursors of the phases which are refractory to sulphurization The presence of all these species leads to a non negligible indirect loss of the catalytic activity of the associated hydrotreatment catalyst because the all the elements belonging to at least one Group VIB metal and / or at least one Group VIII metal is not used to its full potential since a part of these is immobilized in little or no active species.

The catalytic performances of the conventional hydrotreatment catalysts described above could therefore be improved, in particular by developing new methods for preparing these catalysts which would make it possible: 1) to ensure good dispersion of the active phase, in particular for contents such as by controlling the size of the transition metal-based particles and maintaining the properties of these particles after heat treatment, 2) limiting the formation of refractory species to sulfurization for example by obtaining a better synergy between the transition metals constituting the active phase and the control of the interactions between the active phase and / or its precursors and the porous support used, 3) to ensure a good diffusion of the reactants and the products of the reactions while maintaining high developed active surfaces for example by optimizing property s chemical, textural and structural porous support.

Several lines of research concerning the development of new hydrotreatment catalysts have attempted to meet the needs expressed above. The research work of the applicant has therefore led to the preparation of hydrotreating and / or hydroisomerization catalysts by modifying the chemical and structural composition of the precursor metal species of the active phases and thus by modifying the interactions between the support and the active phase of the catalyst and / or its precursor oxides. In particular, the work of the applicant has led to the use of polyoxometalates whose formula is explained below as particular oxide precursors of the active phase of the catalysts used in the process for producing middle distillates according to the invention and in particular in the hydrotreatment step and / or in the hydroisomerization step. Furthermore, the oxide support of the catalyst plays a significant role in the development of efficient hydrotreatment catalysts insofar as it will induce modifications of the interactions between the support and the active phase of said catalyst and / or its precursor oxides. Applicant has also directed his research work towards the preparation of hydrotreatment catalysts using oxide supports having particular textural properties. The Applicant has thus demonstrated that a catalyst comprising, in its oxide form, at least one active phase precursor in the form of at least one polyoxometalate of formula (HhXXMn, OY) q - explained below, trapped within even of a silicic mesostructured oxide support matrix, exhibited an improved catalytic activity compared to catalysts prepared from standard precursors not containing polyoxometalates, said catalyst being sulphurized and then used in a process for producing middle distillates according to the invention. An object of the present invention is to provide a process for middle distillates of at least one feedstock derived from renewable sources using, in at least one hydrotreatment step and / or at least one hydroisomerization step, a catalyst having improved catalytic performance.

Another object of the present invention is to provide a process for middle distillates of at least one feedstock derived from renewable sources using, in at least one hydrotreatment step and / or at least one hydroisomerization step, a catalyst having improved catalytic performance, said process making it possible to obtain the production of paraffins meeting the fuel specifications and in particular the standards in force for the diesel and kerosene fuels constituting the middle distillates and in particular with high cetane number.

SUMMARY OF THE INVENTION The invention relates to a method for producing middle distillates from at least one feedstock from renewable sources comprising at least one hydrotreatment stage in which at least said feedstock is brought into contact with at least one feedstock. hydrotreatment catalyst at a temperature between 120 and 450 ° C, at a pressure of between 1 and 10 MPa, at a space velocity of between 0.1 and 10 h -1 and in the presence of a hydrogen / charge ratio between 50 and 3000 Nm3 of hydrogen / m 3 of feedstock and at least one hydroisomerization step in which the effluent from step a) is brought into contact with at least one hydroisomerization catalyst at a temperature between 120 and 450 ° C., at a pressure of between 1 and 10 MPa, at a space velocity of between 0.1 and 10 h -1 and in the presence of a hydrogen / charge ratio of between 50 and 3000 Nm 3 of hydrogen. / m3 of charge, said hydro step treatment and / or said hydroisomerisation step using a catalyst comprising, in its oxide form, at least one Group VIB metal and / or at least one Group VIII metal of the periodic classification present in the form of at least one polyoxometalate of formula (HhXXMn, Oy) q "wherein X is a member selected from phosphorus (P), silicon (Si), boron (B), nickel (Ni) and cobalt (Co) , said element being taken alone, M is one or more element (s) chosen from molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co), O being oxygen where h is an integer from 0 to 12, where x is an integer from 0 to 4, where m is an integer of 5, 6, 7, 8, 9, 10, 11, 12 and 18, where y is an integer between 17 and 72 and q being an integer between 1 and 20, said polyoxometalates being present within an oxide-based mesostructured matrix of at least one Y element selected from the group consisting of by silicon, aluminum, titanium, zirconium, gallium, and cerium and the mixture of at least one of these elements, said matrix having a pore size of between 1.5 and 50 nm and exhibiting amorphous walls with a thickness between 1 and 30 nm, said catalyst being sulphurized before being used in said process.

One of the advantages of the present invention therefore lies in the implementation, in a method for producing middle distillates from at least one feedstock from renewable sources, of a catalyst, in at least one step a) of hydrotreatment and / or at least one hydroisomerization step b), simultaneously exhibiting the catalytic properties specific to the presence of polyoxometalates and the surface reactivity properties of the mesostructured oxide matrix in which said polyoxometalates are trapped. This results in innovative properties and interactions between said polyoxometalates and the mesostructured inorganic network of said matrix. These interactions result in an increased hydrotreatment and hydroisomerization activity compared to the catalysts described in the prior art, this being due in particular to a better dispersion of the active phase through the use of a mesostructured oxide matrix in which are entrapped polyoxometalates. These interactions also result in an increase in the yield of middle distillates obtained at the end of the process. The invention relates to a process for producing middle distillates from at least one feedstock from renewable sources.

Charges The feedstock used in the process for producing middle distillates according to the invention is advantageously chosen from oils and fats of vegetable or animal origin, or mixtures of such fillers, containing triglycerides and / or fatty acids. free and / or esters. The vegetable oils may advantageously be crude or refined, wholly or in part, and derived from plants selected from rapeseed, sunflower, soybean, palm, palm kernel, olive, coconut, jatropha, taken alone. or in a mixture, this list not being limiting. Algae or fish oils can also be advantageously used. The oils can also advantageously be produced from genetically modified organisms. Animal fats are advantageously chosen from lard or fats composed of residues from the food industry or from catering industries taken alone or as a mixture.

These fillers essentially contain triglyceride-type chemical structures which are also known to those skilled in the art as tri-ester of fatty acids as well as free fatty acids. A tri-ester of fatty acid is thus composed of three fatty acid chains esterified to a glycerol root. These fatty acid chains in the form of tri-ester or in the form of free fatty acid have a number of unsaturations per chain generally between 0 and 3, but which may be higher, especially for the oils derived from algae which present generally, a number of chain unsaturations of 5 to 6. The molecules present in the feeds from renewable sources used in the present invention therefore have a number of unsaturations, expressed per molecule of triglyceride, advantageously between 0 and 18. In these charges, the unsaturation rate, expressed as the number of unsaturations per hydrocarbon fatty chain, is advantageously between 0 and 6. The charges from renewable sources have an iodine number of from 0 to 600 s, generally from 5 to 200, and an oxygen content of 5 to 20% by weight and preferably 8% by weight and 13% by weight. The charges from renewable sources may have nitrogen contents of between 1 ppm and 500 ppm by weight.

Preferably, said feedstock from renewable sources used in the process according to the invention is pretreated beforehand or pre-refined so as to eliminate, by appropriate treatment, contaminants naturally present in bio-liquids of renewable origin such as alkali metals, alkaline earth metals, and transition metals as well as nitrogen. Suitable treatments may for example be heat and / or chemical treatments, which are well known to a person skilled in the art of refining. Preferably, the optional pretreatment step consists of a mild pre-hydrogenation of said feedstock so as to hydrogenate the reactive unsaturations in the presence of a pre-hydrogenation catalyst. Said mild pre-hydrogenation step advantageously operates at a temperature of between 50 ° C. and 400 ° C. and at a hydrogen pressure of between 0.1 and 10 MPa and, preferably, at a temperature of between 150 ° C. and 200 ° C. The pre-hydrogenation catalyst advantageously comprises metals of group VIII and / or VIB and, preferably, the pre-hydrogenation catalyst is a catalyst based on palladium, platinum, nickel, nickel and molybdenum or based on cobalt and molybdenum, dispersed on a metal oxide or a mixture of oxides such as supports alumina, silica, titanium, zeolite, etc. The metals of the catalysts used in said soft pre-hydrogenation step are sulphide metals or metal phases and preferably metal phases.

More particularly, the invention relates to a process for producing middle distillates from at least one feedstock derived from renewable sources comprising at least one hydrotreating step and at least one hydroisomerization step. The catalysts described according to the invention can be used in the hydrotreatment step and / or in the hydroisomerization step. The hydrotreating step notably allows the elimination of the heteroatoms (oxygen and nitrogen) present in said feedstock and the production of paraffinic hydrocarbons. The hydroisomerization step of the paraffinic effluent from the hydrotreatment stage allows the production of middle distillates with improved cold properties. Said method according to the invention can advantageously be implemented in two steps or in a single step. Thus, the hydrotreatment step and the hydroisomerization step may advantageously be carried out in two separate reactors or in a single reactor.

In the preferred case where said process according to the invention is carried out in two steps, the hydrotreatment step and the hydroisomerization step of said process are carried out in two separate reactors. In this case, and in the case where the hydrotreatment step and the hydroisomerization step use a catalyst described according to the invention, the hydrotreatment stage advantageously employs a catalyst comprising a mesostructured matrix consisting of of silicon oxide and the hydroisomerization step advantageously employs a catalyst comprising a mesostructured matrix comprising a mixture of silicon oxide and aluminum oxide. In the preferred case where said process according to the invention is carried out in two stages, and in the case where the catalyst described according to the invention is used in only one of the two stages of hydrotreatment and hydroisomerisation, the The catalyst of the other step is advantageously a conventional hydrotreating and hydroisomerization catalyst of the prior art. The conventional hydrotreatment catalyst advantageously comprises at least one group VIII element and / or at least one group VIB element and optionally at least one doping element chosen from phosphorus, boron and silicon and an alumina or silica alumina support. The conventional hydroisomerization catalyst advantageously comprises at least one element of noble or non-noble group VIII and / or at least one element of group VIB and optionally at least one doping element chosen from phosphorus, boron and silicon and a chosen support among alumina, silica alumina and zeolites known to those skilled in the art. In the case of the use of noble metals, the active phase is in metallic form and in the case of the use of non-noble metals, the active phase is in sulphide form. The hydrotreatment and hydroisomerization catalysts may also advantageously be chosen from the hydrotreatment and hydroisomerization catalysts described in patents FR 2 910 483 and FR 2 932 811. In the preferred case where said process according to the invention is implemented in a single step, the hydrotreating step and the hydroisomerization step of said process are carried out in a single reactor. In this case, said hydrotreatment and hydroisomerization steps are carried out in the presence of a single catalyst according to the invention comprising a mesostructured matrix consisting of silicon oxide. Said hydrotreatment and hydroisomerization stages are advantageously implemented in a fixed bed.

Said process according to the invention can thus advantageously be carried out industrially in one or more reactors with one or more identical or different catalytic beds, with a combined upward or downward flow of gas and liquid and preferably downflow.

In the preferred case where said process according to the invention is carried out in a single step, said process advantageously operates at a temperature of between 250 ° C. and 400 ° C., and preferably between 300 ° C. and 430 ° C., at a total pressure of between 3 and 9 MPa and preferably between 5 and 9 MPa, at a space velocity of between 0.1 and 5 h and preferably between 0.3 and 3 h and in the presence of a total amount of hydrogen mixed with the feed such that the hydrogen / feed ratio is between 100 and 2000 Nm3 of hydrogen / m3 of feedstock and preferably between 300 and 1500 Nm3 of hydrogen / m3 of feedstock.

In the preferred case where said process according to the invention is carried out in two steps, the hydrotreatment step advantageously operates at a temperature of between 120 ° C. and 350 ° C., and preferably between 150 ° C. and 330 ° C. C, at a total pressure of between 3 and 9 MPa and preferably between 4 and 8 MPa, at a space velocity of between 0.1 and 5 hours and preferably between 0.3 and 3 hours. presence of a total amount of hydrogen mixed with the feed such that the hydrogen / feed ratio is between 100 and 2000 Nm3 of hydrogen / m3 of feedstock and preferably between 300 and 1500 Nm3 of hydrogen / m3 feedstock.

In the preferred case where said process according to the invention is carried out in two stages, the hydroisomerization step advantageously operates at a temperature of between 250 ° C. and 400 ° C., and preferably between 300 ° C. and 430 ° C. C, at a total pressure of between 3 and 9 MPa and preferably between 5 and 9 MPa, at a space velocity of between 0.1 and 5 hours and preferably between 0.3 and 3 hours. presence of a total amount of hydrogen mixed with the feed such that the hydrogen / feed ratio is between 100 and 2000 Nm3 of hydrogen / m3 of feedstock and preferably between 300 and 1500 Nm3 of hydrogen / m3 feedstock.

In the preferred case where said process according to the invention is implemented in two steps, at least one separation step and preferably a gas / liquid separation step and a step of separation of the water and at least one Liquid hydrocarbon base is advantageously used between the hydrotreating step and the hydroisomerization step of the process according to the invention. The effluent from the hydrotreatment stage therefore preferably undergoes a gas / liquid separation step followed by a step of separation of at least a portion of the water and at least one liquid hydrocarbon base, said steps that can be implemented in an indifferent order with respect to each other. The gas / liquid separation step of the effluent resulting from the hydrotreatment step makes it possible to separate the gases from the liquid, and preferably to recover the hydrogen-rich gases that also contain gases such as carbon monoxide (CO ), carbon dioxide (CO2), and hydrogen sulfide (H2S) and propane and at least one liquid effluent. Said recovered gases can advantageously also be purified by methods known to those skilled in the art such as methanation for the conversion of CO to CO2 and washing with amines for the removal of CO2.

Preferably, the liquid effluent resulting from said gas / liquid separation then undergoes a separation of at least a portion and preferably all of the water formed, and at least one liquid hydrocarbon effluent, the water being produced during the hydrodeoxygenation reactions taking place in the hydrotreating step. Said step makes it possible to separate the water from the liquid hydrocarbon effluent. The removal of water can be carried out by any method and technique known to those skilled in the art, such as, for example, by drying, drying on a desiccant, flash, extraction by solvent, distillation and decantation or by combination of at least two of these methods. A final purification step of the various pollutants present in said liquid hydrocarbon effluent can advantageously be implemented by methods known to those skilled in the art such as, for example, by stripping with steam or with nitrogen or by coalescence and / or capture mass. The liquid hydrocarbon effluent resulting from the step of separating at least part of the water or preferably from said final purification stage generally contains residual organic nitrogen compounds that are not removed during the hydrodeoxygenation reactions of the process according to the invention. 'invention. The said residual nitrogenous organic compounds are inhibitors of the hydroisomerization catalysts, they must therefore be removed from the said liquid hydrocarbon effluent before it passes into the hydroisomerisation stage. Thus, a step of removing nitrogen compounds from said obtained liquid hydrocarbon base can advantageously be carried out between the hydrotreatment step according to the invention and the hydroisomerization step, preferably after said step of separating the water. at least a portion of the water and preferably after said final purification step. Said step of eliminating the residual nitrogen compounds can advantageously be carried out by all the techniques known to those skilled in the art, such as for example the use of capture masses. By capture mass we mean the activated or non-activated aluminas, the mesoporous aluminosilicates, the zeolites, the activated carbons, and the ion exchange resins. Preferably, the step of removing the nitrogenous organic compounds is carried out on an ion exchange resin.

According to the invention, the effluent from the hydrotreatment step, optionally separated and / or purified in the case where said process is carried out in two stages, then undergoes a hydroisomerization step, said hydroisomerization step which can be carried out in the presence of a catalyst according to the invention described below. The effluent from the hydroisomerization step is then advantageously subjected at least in part, and preferably in all, to one or more separations. The purpose of said step (s) is to separate the gases from the liquid, and in particular to recover the hydrogen-rich gases that may also contain light gases such as the C 1 -C 4 cut and at least one gas oil cut. a naphtha cut. The recovery of the naphtha fraction is not the subject of the present invention, but this section can advantageously be sent to a steam cracking or catalytic reforming unit.

It is well known to those skilled in the art that the hydrotreatment reactions of charges from renewable sources are very exothermic. They are accompanied by the release of a large amount of heat. This results in a large increase in the temperature of the reaction medium which may cause undesirable effects. Moreover, the temperature has an effect of increasing the speed of the reaction which will then release even more heat. This type of self-maintained phenomenon must be controlled under pain of seeing it diverge to very high temperatures that may reach levels higher than the melting points of the reactor materials. Without going to this end, the high temperatures favor the cracking reactions forming light hydrocarbons (methane, ethane) difficult to recover and reduce the amount of gasoline and kerosene fuel bases produced. In general, it appears essential to control the increase in the temperature associated with the implementation of the exothermic reactions targeted by the invention both for reasons of safety and overall efficiency of the process. For this, various techniques well known to those skilled in the art are conceivable, such as the staged injection method of the load described in the patent application WO2008 / 058664.

According to the invention, said hydrotreatment step and / or said hydroisomerization step use a catalyst comprising in its oxide form, that is to say before having undergone a sulphurization step generating the active sulphide phase, at at least one Group VIB metal and / or at least one Group VIII metal of the Periodic Table, taken alone or as a mixture, said metals being present in the form of at least one polyoxometalate of formula (HhXXMmOy) p- explained above said polyoxometalates being present within a mesostructured oxide matrix. More specifically, said polyoxometalates present within said matrix are trapped in the walls of said matrix. Said polyoxometalates are therefore not simply deposited for example by impregnation on the surface of the pores of said matrix but are located within the walls of said matrix. The particular localization of said polyoxometalates within the walls of said mesostructured oxide matrix allows a better interaction between said support matrix and the active phase and / or its precursor oxides comprising said polyoxometalates. This also results in an improvement in the maintenance of the textural and structural properties of the mesostructured oxide matrices, an improvement in the maintenance of the structure of said polyoxometalate and preferably in said heteropolyanion after post-treatment of the final solid, as well as an improvement in the dispersion, the thermal resistance and the chemical resistance of said polyoxometalate.

By abuse of language and throughout the rest of the text, we define the polyoxometalates used according to the invention, as being the compounds corresponding to the formula (HhXXMmOy) 4 "in which X is a member selected from phosphorus (P), silicon (Si), boron (B), nickel (Ni) and cobalt (Co), said element being taken alone, M is one or more element (s) chosen from molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co), where 0 is oxygen, h being an integer between 0 and 12, x being an integer between 0 and 4, m being an integer equal to 5 , 6, 7, 8, 9, 10, 11, 12 and 18, where y is an integer from 17 to 72 and q is an integer from 1 to 20. Preferably the element M can not be an atom of nickel or a cobalt atom alone.

The polyoxometalates defined according to the invention include two families of compounds, isopolyanions and heteropolyanions. These two families of compounds are defined in the article Heteropoly and Isopoly Oxometallates, Pope, Ed Springer-Verlag, 1983. The isopolyanions which can be used in the present invention are polyoxometalates of general formula (HhXXM, Oy) q "in which x = 0, the other elements having the abovementioned meaning Preferably the m atoms M of said isopolyanions are either only molybdenum atoms, or only tungsten atoms, or a mixture of molybdenum and cobalt atoms, or one a mixture of atoms of molybdenum and nickel, a mixture of tungsten and cobalt atoms, or a mixture of tungsten and nickel atoms, of the m atoms M of said isopolyanions, the group VIII elements are partially substituted to the elements of group VIB, in particular, in the case where the m atoms M are either a mixture of molybdenum and cobalt atoms, or a mixture of molybdenum and nickel, or a m lange atoms of tungsten and cobalt, or a mixture of tungsten atoms and nickel atoms of cobalt and nickel is partially substituted for atoms of molybdenum and tungsten. The m atoms M of said isopolyanions may also advantageously be either a mixture of nickel, molybdenum and tungsten atoms, or a mixture of cobalt, molybdenum and tungsten atoms. Preferably, in the case where the element M is molybdenum (Mo), m is equal to 7. Similarly, in the case where the element M is tungsten (W), m is equal to 12 The isopolyanions Mo, O246- and H2W12O406 "are advantageously used as active phase precursors in the context of the invention and preferably a very preferred isopolyanion used as active phase precursor of the catalyst employed in the step of hydrotreatment and / or the hydroisomerization step of the process according to the invention is the isopolyanion of formula H2W12O406 Said isopolyanions are advantageously formed by reaction of oxoanions of MO42 - type with each other. For example, the molybdic compounds are well known for this kind of reactions, since depending on the pH, the molybdic compound in solution can be in the form MoO42 "or in the form of an isopolyanion of formula Mo70246- which is obtained according to reaction: 7 MoO42- + 8H + -> Mo, 0246- + 4H2O In the case of isopolyanions in which M is a tungsten atom, the potential acidification of the reaction medium, causing the formation of tungstates W042 can lead to to generate the α-metatungstate, 12 times condensed according to the following reaction: 12 W042 "+ 18 H + -> H2W120406_ + 8 H2O. The heteropolyanions which may be used in the present invention are polyoxometalates of the formula (HhXXMn, Oy) q "in which x = 1, 2, 3 or 4, the other elements having the above-mentioned meaning.

The heteropolyanions generally have a structure in which the element X is the "central" atom and the element M is a metal atom that is practically systematically in octahedral coordination with X. Preferably, the m atoms M are either only atoms of Molybdenum, either only tungsten atoms, or a mixture of molybdenum and cobalt atoms, or a mixture of molybdenum and nickel, or a mixture of tungsten and molybdenum atoms, or a mixture of tungsten atoms and cobalt, a mixture of tungsten atoms and nickel. Preferably, the m atoms M are either only molybdenum atoms, or a mixture of molybdenum and cobalt atoms, or a mixture of molybdenum and nickel. Preferably, the m atoms M can not be only nickel atoms, or only cobalt atoms. Among the m atoms M of said heteropolyanions, the elements of group VIII partially replace the elements of group VIB. In particular, in the case where the m atoms M are either a mixture of molybdenum and cobalt atoms, or a mixture of molybdenum and nickel, or a mixture of tungsten and cobalt atoms, or a mixture of At the tungsten and nickel atoms, the cobalt and nickel atoms partially substitute for the molybdenum and tungsten atoms and preferably for the molybdenum atoms. Preferably, the element X is at least one phosphorus atom.

The heteropolyanions are advantageously obtained by polycondensation of oxoanions of M042 - type in the case where M is a molybdenum or tungsten atom around one or more oxoanion (s) of the type X04q "in which the charge q is dictated by the byte rule and the position of the X element in the periodic table. There is then elimination of water molecules and creation of oxo bridges between the atoms. These condensation reactions are governed by various experimental factors such as pH, the concentration of species in solution, the nature of the solvent, and the ratio m / x being the ratio of the number of atoms of element M to the number of atoms. of element X.

Heteropolyanions are negatively charged polyoxometallate species. To compensate for these negative charges, it is necessary to introduce counter ions and more particularly cations. These cations may advantageously be H + protons, or any other cation of NH 4 + type or metal cations and in particular metal cations of Group VIII metals. In the case where the counterions are protons, the molecular structure comprising the heteropolyanion and at least one proton constitutes a heteropolyacid. The heteropolyacids which can be used as active phase precursors in the present invention may be, for example, phosphomolybdic acid (3H +, PMo12O403 ") or phosphotungstic acid (3H +, PW12O403) - in the case where the -ions are not protons, one speaks then of heteropolyanion salt to designate this molecular structure, one can then advantageously profit from the association within the same molecular structure, via the use of a salt of heteropolyanion, of the metal M and its promoter, that is to say of the cobalt element and / or of the nickel element which can either be in position X within the structure of the heteropolyanion, or in partial substitution of at least one M molybdenum and / or tungsten atom within the structure of the heteropolyanion is in a counter-ion position.

Preferably, the polyoxometalates used according to the invention are the compounds corresponding to the formula (HhXXMrr, Oy) q- in which X is an element chosen from phosphorus (P), silicon (Si) and boron (B). , nickel (Ni) and cobalt (Co), said element being taken alone, M is one or more element (s) chosen from molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co) where O is oxygen, h being an integer from 0 to 6, where x is an integer possibly equal to 0, 1 or 2, m being an integer equal to 5, 6, 7, 9 , 10, 11 and 12, y being an integer between 17 and 48 and q being an integer of 3 to 12. More preferably, the polyoxometalates used according to the invention are the compounds corresponding to the formula (HhXXMn, Wherein h is an integer of 0, 1, 2, 4 or 6, where x is an integer of 0, 1 or 2, m being an integer of 5, 6, 10, 11 or 12, y being an integer equal to 23, 24, 38, 39 or 40 and q being an integer equal to 3, 4, 6 and 7, X, M and O having the above meaning. The preferred polyoxometalates used according to the invention are advantageously chosen from polyoxometalates of formula H 2 W 12 O 406, PMO 12 O 40 3 PW 12 O 40 3, HP NiMo 4 O 406-, P2Mo 5 O 2 36 -, NiMo 6 O 24 H 6 O - and Ni 2 MoO 10 O 38 H 48 -, taken alone or as a mixture of preferred polyoxometalates which can advantageously be used as active phase precursors of the catalyst used in the hydrotreating step and / or the hydroisomerization step of the process according to the invention are so-called Anderson heteropolyanions of general formula XM6O24a- for which the ratio m / x is equal to 6 and in which the elements X and M and the charge q have the abovementioned meaning, the element X is therefore an element chosen from phosphorus (P), silicon (Si), boron (B), nickel (Ni) and cobalt (Co), said element being taken alone, M is one or more element (s) chosen from molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co), and q is a integer between 1 and 20 and preferably between 3 and 12.

The particular structure of said so-called Anderson heteropolyanions is described in the article Nature, 1937, 150, 850. The structure of said so-called Anderson heteropolyanions comprises 7 octahedra located in the same plane and interconnected by the edges: of the 7 octahedra, 6 octahedra surround the central octahedra containing the element X. Anderson heteropolyanions containing within their structure cobalt and molybdenum or nickel and molybdenum are preferred. Anderson heteropolyanions of the formula CoMo6O24H63- and NiMo6O24H64- are particularly preferred In accordance with the formula, in these Anderson heteropolyanions, the cobalt and nickel atoms are respectively the heteroelements X of the structure.

Indeed, said heteropolyanions combine in the same structure molybdenum and cobalt or molybdenum and nickel. In particular, these allow, when they are in the form of cobalt salts or nickel salts, to reach an atomic ratio of said promoter on the metal M and in particular an atomic ratio (Co and / or Ni) / Mo between 0.4 and 0.6. This ratio of said promoter (Co and / or Ni) / Mo of between 0.4 and 0.6 is particularly preferred for maximizing the performance of hydrotreatment catalysts and in particular hydrodesulphurization catalysts used in the process according to the invention . In the case where the Anderson heteropolyanion contains within its structure cobalt and molybdenum, a mixture of the two monomeric forms of formula CoMo 6 O 24 H 63 and dimeric formula Co 2 MoI O 38 H 46 of said heteropolyanion, the two forms being in equilibrium, can advantageously be used. In the case where the Anderson heteropolyanion contains within its structure cobalt and molybdenum, said Anderson heteropolyanion is preferably dimeric of formula Co2MoI0038H46-. In the case where the Anderson heteropolyanion contains within of its structure of nickel and molybdenum, a mixture of the two monomeric forms of formula NiMo6O24H64 "and dimeric formula of Ni2Mo10038H48" of said heteropolyanion, the two forms being in equilibrium, may advantageously be used In the case where the heteropolyanion of Anderson contains in its structure nickel and molybdenum, said Anderson heteropolyanion is preferably monomeric of formula NiMo6O24H64 Salts of Anderson heteropolyanions can also be advantageously used as active phase precursors according to the invention. Anderson heteropolyanions are advantageously chosen from the cobalt or nickel salts of the mono ion. 6-molybdocobaltate, respectively, of formula CoMo6O24H63-, 3 / 2Co2 + or COMo6O24H63 ", 3 / 2Ni2 + having an atomic ratio of said promoter (Co and / or Ni) / Mo of 0.41, cobalt or nickel salts of dimeric decamolybdocobaltate ion of the formula Co2Mo10O38H46-, 3Co2 + or Co2MoI0038H46-, 3Ni2 + having an atomic ratio of said promoter (Co and / or Ni) / Mo of 0.5, the cobalt or nickel salts of the 6-molybdonickellate ion of the formula NiMo6O24H64 2Co2 + or NiMo6O24H64 2Ni2 + having an atomic ratio of said promoter (Co and / or Ni) / Mo of 0.5, and the cobalt or nickel salts of the dimeric decamolybdonickellate ion of formula Ni2MoI0038H48 ", 4Co2 + or Ni2Mo, 0038H48- , 4Ni2 + having an atomic ratio of said promoter (Co and / or Ni) / Mo of 0.6. The most preferred Anderson heteropolyanions used in the invention are Anderson heteropolyanions containing within their structure nickel and molybdenum of the formula MM06O24H64- and Ni2Mo10O38H48- alone or in admixture.

Other preferred polyoxometalates which can advantageously be used as precursors for the active phase of the catalyst used in the hydrotreatment step and / or the hydroisomerization step of the process according to the invention are the so-called Keggin heteropolyanions of formula XM12O404- for which the ratio m / x is equal to 12 and the heteropolyanions said Keggin lacunar of general formula XM11O394 "for which the ratio m / x is equal to 11 and in which the elements X and M and the load q have X is therefore an element chosen from phosphorus (P), silicon (Si), boron (B), nickel (Ni) and cobalt (Co), said element being taken alone, M is a or more element (s) chosen from molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co), and q being an integer between 1 and 20 and preferably between 3 and 12. The said Keggin species are advantageously obtained for variable pH ranges according to the routes of production described in the publication by A. Griboval, P. Blanchard, E. Payen, M. Fournier, J. L. Dubois, Chem. Lett., 1997, 12, 1259. Preferred Keggin heteropolyanions, advantageously used as active phase precursor according to the invention, are the heteropolyanions of formula PMo12O403- and PW12O4 3-taken alone or as a mixture. The preferred Keggin heteropolyanions may also be advantageously used in the invention in their heteropolyacid form of the respective formulas PM012O403-, 3H + and PW120403, 31- + alone or as a mixture.

In said Keggin heteropolyanions of the above formula, at least one molybdenum atom is substituted with a nickel atom, a cobalt atom or at least one vanadium atom, respectively.

Said heteropolyanions mentioned above are described in the publications of L. G. A. van de Water, J. A. Bergwerff, B. R. G. Leliveld, B. M. Weckhuysen, K. P. de Jong, J. Phys. Chem. B, 2005, 109, 14513 and D. Soogund, P. Lecour, A. Daudin, B. Guichard, C. Legens, C. Lamonier, E. Payen in Appl. Catal. B, 2010, 98, 1, 39. Keggin or Keggin lacunar heteropolyanion salts can also be advantageously used as active phase precursors according to the invention. Preferred Keggin and Keggin lacunary heteropolyanion or heteropoly acid salts are preferably selected from cobalt or nickel salts of phosphomolybdic, silicomolybdic, phosphotungstic or silicotungstic acids. Said heteropolyanion or heteropolyacid salts of the Keggin or Keggin lacunary type are described in the patent US2547380. Preferably, a Keggin type heteropolyanion salt is the nickel phosphotungstate of formula 3 / 2Ni 2+, PW12O403_ having an atomic ratio of the Group VI metal to the Group VIII metal, ie NO of 0.125.

Other salts of heteropolyanions or of heteropolyacids of the Keggin or Keggin lacunary type which can advantageously be used as active phase precursors according to the invention are the heteropolyanion or heteropoly acid salts of general formula ZxXM12040 (or xZP +, XM12040 ( Px), formula showing the ZP +) counterion, in which Z is cobalt and / or nickel, X is phosphorus, silicon or boron and M is molybdenum and / or tungsten, x takes the value of 2 or more if X is phosphorus, 2.5 or more if X is silicon and 3 or more if X is boron. Such heteropolyanion or heteropolyacid salts of the Keggin or Keggin lacunary type are described in patent FR2749778. These structures are of particular interest over the structures described in US Pat. No. 5,447,380 to achieve atomic ratios of the Group VIII element on the higher Group VI element and in particular greater than 0.125. This increase in said ratio is obtained by reducing said salts of heteropolyanions or heteropolyacids of Keggin or Keggin lacunary type. Thus the presence of at least a portion of the molybdenum and / or tungsten is at a valence lower than its normal value of six as it results from the composition, for example, phosphomolybdic, phosphotungstic, silicomolybdic or silicotungstic acid . Atomic ratios of the group VIII element to the higher group VI element are particularly preferred for maximizing the performance of hydrotreatment catalysts and in particular hydrodesulphurization catalysts used in the process according to the invention.

The substituted Keggin heteropolyanion salts of formula ZxXM11040Z'C (z_2x) in which Z 'is substituted for an M atom and in which Z is cobalt and / or nickel, X is phosphorus, silicon or boron and M is molybdenum and / or tungsten, Z 'is cobalt, iron, nickel, copper or zinc, and C is an H + ion or an alkylammonium cation, x is 0 to 4.5, z a value between 7 and 9, said salts being described in patent FR2764211 may also be advantageously used as active phase precursors according to the invention. Thus, said salts of Keggin heteropolyanions correspond to those described in patent FR2749778 but in which a Z 'atom is substituted for an M atom. Said substituted Keggin heteropolyanion salts are particularly preferred because they lead to atomic ratios between group VIII and group VI up to 0.5.

The nickel salts of a heteropolyanion of the Keggin lacunary type described in the patent application FR2935139 may also be advantageously used as active phase precursors according to the invention. The nickel salts of a lacunar Keggin type heteropolyanion comprising in its tungsten structure have a general formula Nix + y / 2XW11-yO39-5 / 2y, zH2O in which Ni is nickel, X is selected from phosphorus, silicon and boron, W is tungsten, O is oxygen, y = 0 or 2, x = 3.5 if X is phosphorus, x = 4 if X is silicon, x = 4.5 if X is boron and z is a number from 0 to 36, and wherein said molecular structure has no nickel atom substituted for a tungsten atom in its structure, said nickel atoms being placed in a counter-ion position in the structure of said compound. An advantage of this invention lies in the greater solubility of these heteropolyanion salts. Other preferred polyoxometalates which can advantageously be used as active phase precursors of the catalyst used in the process according to the invention are so-called Strandberg heteropolyanions of formula HhP2Mo5O23 (6-h) - in which h is equal to 0, 1 or 2 and for which the ratio m / x is equal to 5/2. The preparation of said Strandberg heteropolyanions is described in the article of W-C. Cheng, NP Luthra, J. Catal., 1988, 109, 163. It has thus been shown by JA Bergwerff, T. Visser, BRG Leliveld, BD Rossenaar, Jong KP, BM Weckhuysen, Journal of the American Chemical Society 2004, 126, 44, 14548. A particularly preferred Strandberg heteropolyanion used in the invention is the heteropolyanion of formula P2Mo5O236-. Thus, thanks to various preparation methods, many polyoxometalates and their associated salts are available with varying promoter X / metal M ratios. In general, all these polyoxometalates and their associated salts can be advantageously used for the preparation of catalysts covered in the process according to the invention. The foregoing list is however not exhaustive and other combinations may be envisaged.

The use of polyoxometalates for the preparation of catalysts used in the process according to the invention has many advantages from the catalytic point of view. Said polyoxometalates which are oxidation precursors associating within the same molecular structure at least one element of group VIB, preferably molybdenum and / or tungsten and / or at least one element of group VIII, preferably cobalt and / or nickel, lead, after sulfurization, catalysts whose catalytic performance is improved through a better promotional effect that is to say a better synergy between the group VIB element and the group VIII element.

Preferably, in the case where the catalyst used in the process according to the invention comprises a group VIB element, said catalyst comprises a mass content of the group VIB element expressed as a percentage by weight of oxide relative to the total mass of the catalyst between 2 and 35% by weight and preferably between 5 and 250/0 by weight. Said contents are the total contents of group VIB element irrespective of the form of said group VIB element present in said catalyst and possibly regardless of its mode of introduction. Said contents are therefore representative of the content of group VIB element present either in the form of at least one polyoxometalate within the mesostructured oxide matrix, or in any other form depending on its mode of introduction, such as for example in the form of oxide.

Preferably, in the case where the catalyst used in the process according to the invention comprises a group VIII element, said catalyst comprises a mass content of the group VIII element expressed as a percentage by weight of oxide relative to the total mass of the catalyst between 0.1 and 10% by weight and preferably between 1 and 7% by weight. Said contents are the total group VIII element content irrespective of the form of said group VIII element present in said catalyst and possibly regardless of its mode of introduction. Said contents are therefore representative of the element content of the group VIII present either in the form of at least one polyoxometalate within the mesostructured oxide matrix, whether in the M-position or in the X-position, or present in the form of against and optionally added to different stages of the preparation of said mesostructured oxide matrix as described below, or in any other form depending on its mode of introduction, such as for example in oxide form.

Preferably, in the case where the catalyst used in the process according to the invention comprises a doping element chosen from phosphorus, boron and silicon, said catalyst comprises a mass content of doping element chosen from phosphorus, boron and the silicon, expressed as a percentage by weight of oxide relative to the total mass of the catalyst, of between 0.1 and 10% by weight and preferably between 0.1 and 5% by weight. Said contents are the total contents of doping element chosen from phosphorus, boron and silicon whatever the form of said doping element present in said catalyst and whatever its mode of introduction. Said contents are therefore representative both of the content of doping element chosen from phosphorus, boron and silicon present in the form of at least one polyoxometalate within the mesostructured oxide matrix at position X and / or possibly added to different steps of the preparation of said mesostructured oxide matrix as described below, or in any other form depending on its mode of introduction, such as for example in oxide form.

According to the invention, said polyoxometalates defined above are present in a mesostructured matrix based on an oxide of at least one Y element chosen from the group consisting of silicon, aluminum, titanium and zirconium. , gallium, and cerium and the mixture of at least one of these elements, said matrix having a pore size of between 1.5 and 50 nm and having amorphous walls with a thickness of between 1 and 30 nm and preferably between 1 and 10 nm.

For the purposes of the present invention, the term "mesostructured matrix" is intended to mean an inorganic solid having an organized porosity at the mesopore scale of each of the elementary particles constituting said solid, that is to say a porosity organized at the pore scale. having a uniform size of between 1.5 and 50 nm and preferably between 1.5 and 30 nm and even more preferably between 4 and 16 nm and homogeneously and uniformly distributed in each of said particles constituting the matrix. The material located between the mesopores of each of the elementary particles of the oxide matrix of the catalyst precursor used in the process according to the invention is amorphous and forms walls, or walls, whose thickness is between 1 and 30 nm and preferably between 1 and 10 nm. The thickness of the walls corresponds to the distance separating one pore from another pore.

The organization of the mesoporosity described above leads to a structuring of the oxide matrix, which may be hexagonal, vermicular or cubic and preferably hexagonal.

Generally, said so-called mesostructured materials are advantageously obtained by so-called "soft chemistry" synthesis methods (GJ of AA Soler-Illia, C. Sanchez, B. Lebeau, J. Patarin, Chem Rev., 2002, 102, 4093 ) at low temperature by coexistence in aqueous solution or in solvents of marked polarity of inorganic precursors with structuring agents, generally molecular or supramolecular, ionic or neutral surfactants. The control of electrostatic or hydrogen bonding interactions between the inorganic precursors and the structuring agent together with hydrolysis / condensation reactions of the inorganic precursor leads to a cooperative assembly of the organic and inorganic phases generating micellar aggregates of uniformly sized surfactants. and controlled within an inorganic matrix. This phenomenon of cooperative self-assembly governed, inter alia, by the concentration of structuring agent can be induced by progressive evaporation of a solution of reagents whose concentration of structuring agent is lower than the critical micelle concentration, or else via precipitation or direct gelation of the solid when using a precursor solution more concentrated in reagents. The release of the porosity is then obtained by removing the surfactant, which is conventionally carried out by chemical extraction processes or by heat treatment. Depending on the nature of the inorganic precursors and the structuring agent used as well as the operating conditions imposed, several families of mesostructured materials have been developed. The M41 S family consists of mesoporous materials obtained via the use of ionic surfactants such as quaternary ammonium salts, having a generally hexagonal, cubic or lamellar structure, pores of uniform size in a range of 1.5 to 10 nm and amorphous walls of thickness of the order of 1 to 2 nm. The M41 S family was originally developed by Mobil in J. S. Beck, J. C. Vartuli, W. J. Roth, E. Leonowicz, C. T. Kresge, K. D. Schmitt, C.T.-W. Chu, D. H. Oison, E. W. Sheppard, S. B. McCullen, J. B. Higgins, J. L. Schlenker, J. Am. Chem. Soc., 1992, 114, 27, 10834.

The family of materials called SBA is characterized by the use of amphiphilic macromolecular structuring agents of the block copolymer type. These materials are characterized by a generally hexagonal, cubic or lamellar structure, pores of uniform size in a range of 4 to 50 nm and amorphous walls of thickness in a range of 3 to 7 nm. the element Y present in oxide form in said mesostructured matrix is selected from the group consisting of silicon, aluminum, titanium, zirconium, gallium, and cerium and the mixture of at least one of these elements. Preferably, said element Y is selected from the group consisting of silicon, aluminum, titanium, zirconium, and the mixture of at least one of these elements. Preferably, said mesostructured matrix is preferably composed of silicon oxide, in this case said matrix is purely silicic, or of a mixture of silicon oxide and aluminum oxide. Preferably, the hydrotreating step advantageously involves a catalyst comprising a mesostructured matrix consisting of silicon oxide or a mixture of silicon oxide and aluminum oxide and the hydroisomerization step advantageously involves a catalyst comprising a mesostructured matrix comprising a mixture of silicon oxide and aluminum oxide.

In the preferred case where said mesostructured matrix is purely silicic, said matrix is advantageously a mesostructured matrix belonging to the M41 S family or to the family of materials called SBA and preferably an SBA-15 type matrix. In the preferred case where said mesostructured matrix consists of a mixture of silicon oxide and aluminum oxide, said matrix has an Si / Al molar ratio at least equal to 0.02, preferably between 0, 1 and 1000 and very preferably between 1 and 100.

According to the invention, said polyoxometalates defined above are present within a mesostructured oxide matrix. More precisely, said polyoxometalates present within said mesostructured oxide matrix are trapped within said matrix itself. Preferably, said polyoxometalates are present in the walls of said mesostructured matrix. The occlusion of said polyoxometalates in the walls of said mesostructured matrix is achievable by a so-called direct synthesis technique, during the synthesis of said support matrix by adding desired polyoxometallates to the precursor reactants of the inorganic oxide network of the matrix.

Said mesostructured oxide matrix comprising said polyoxometalates entrapped in its walls and used in the process according to the invention is advantageously exclusively prepared by direct synthesis.

More specifically, said mesostructured oxide matrix is advantageously obtained according to a preparation process comprising: a) a step of forming at least one polyoxometalate of the abovementioned formula according to a method known to those skilled in the art, b) a step of mixing into solution of at least one surfactant, at least one silica precursor, at least one precursor of at least one Y element selected from the group consisting of silicon, aluminum, titanium, zirconium, gallium, and the cerium and the mixture of at least one of these elements, then of at least one polyoxometalate obtained according to step a) to obtain a colloidal solution, c) a step of maturing of said colloidal solution obtained at the result of step b) in time and temperature; d) a possible step of autoclaving the suspension obtained at the end of step c), e) a filtration step of the suspension obtained at the end of step c) and after any passage in the step of autoclaving, washing and drying the solid thus obtained, f) a step of removing said surfactant leading to the generation of the uniform and organized mesoporosity of the mesostructured matrix, g) an optional stage of treatment of the solid obtained in the result of step f) to partially or completely regenerate the polyoxometallate entity optionally partially or completely decomposed in step f) and h) an optional step of drying said solid thus obtained consisting of said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls.

Step a) of forming at least one polyoxometalate of the aforementioned formula is advantageously carried out according to a method known to those skilled in the art. Preferably, the polyoxometalates described above and their method of preparation are used in the process for preparing said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls.

Step b) of said preparation process consists of mixing in solution at least one surfactant, at least one silica precursor, with at least one precursor of at least one element Y selected from the group consisting of silicon, aluminum, titanium, zirconium, gallium, and cerium and the mixture of at least one of these elements, then at least one polyoxometallate obtained according to step a) to obtain a colloidal solution . Preferably, at least one surfactant, at least one silica precursor and at least one precursor of at least one Y element selected from the group consisting of silicon, aluminum, titanium, zirconium, gallium, and cerium and the mixture of at least one of these elements are mixed in solution for a period of between 15 minutes and 1 hour, then at least one polyoxometalate obtained according to step a) as a mixture in a solution of the same nature and preferably the same solution is added to the previous mixture to obtain a colloidal solution. The mixing step b) is carried out with stirring at a temperature between 25 ° C and 80 ° C and preferably between 25 ° C and 50 ° C for a period of between 5 minutes and 2 hours and preferably between 30 minutes. minutes and 1 h.

In the case where the element Y selected from the group consisting of silicon, aluminum, titanium, zirconium, gallium, and cerium and the mixture of at least one of these elements, the precursor (s) said element Y is (are) advantageously an inorganic salt of said element Y of formula YZ 2 (n = 3 or 4), Z being a halogen, the group NO 3 or a perchlorate, preferably Z is chlorine. The precursor (s) of said element Y considered may also be a precursor (s) alkoxide (s) of formula Y (OR), or R = ethyl, isopropyl, n -butyl, s-butyl, t-butyl, etc. or a chelated precursor such as Y (C5H802) n, with n = 3 or 4. The precursor (s) of said element Y may also be a (of) oxide (s) or hydroxide (s) of said element Y. Depending on the nature of element Y, the precursor of element Y may also be of the form YOZ2, Z being an anion monovalent as a halogen or NO3 grouping.

In the preferred case where said mesostructured matrix is purely silicic, that is to say in the case where said matrix is made of silicon oxide, at least one silicic precursor is introduced in step b) of mixing in solution. The silicic precursor is advantageously obtained from any source of silica and advantageously from a sodium silicate precursor of formula Na 2 SiO 3, a chlorinated precursor of formula SiCl 4, of an alkoxide precursor of formula Si (OR) 4 where R = H methyl, ethyl or a chloroalkoxide precursor of formula Si (OR) 4 -XCIX where R = H, methyl, ethyl, x being between 0 and 4. The silicic precursor may also advantageously be an alkoxide precursor of formula Si (OR) Where R = H, methyl, ethyl and R 'is an alkyl chain or a functionalized alkyl chain, for example by a thiol, amino, R diketone or sulfonic acid group, x being between 0 and 4. A silicic precursor preferred is tetraethylorthosilicate (TEOS) of formula Si (OEt) 4.

In the preferred case where said mesostructured matrix consists of a mixture of silicon oxide and aluminum oxide, at least one silicic precursor and at least one aluminum precursor can be introduced directly into step b). mixture in solution. In another preferred case where said mesostructured matrix consists of a mixture of silicon oxide and aluminum oxide, only at least one silicic precursor can be introduced into the solution mixing step b). aluminum element that can be introduced by deposition of at least one aluminum precursor on the solid obtained at the end of step e) or at the end of step f). In the case where the aluminum precursor is introduced by deposition on the solid obtained at the end of step f), a complementary heat treatment step is advantageously carried out between steps f) and g) in order to decompose the aluminum precursor. . Said heat treatment is advantageously carried out under the same conditions as the heat treatment of step f) described below. The aluminum precursor is advantageously deposited according to the usual methods well known to those skilled in the art such as, for example, dry impregnation methods or in excess of solvents. The aluminum precursor is advantageously an inorganic aluminum salt of formula AIX3, X being a halogen or the NO3 group. Preferably, X is chlorine. The aluminum precursor may also advantageously be an organometallic precursor of formula AI (OR ") 3 or R" = ethyl, isopropyl, n-butyl, s-butyl or t-butyl or a chelated precursor such as aluminum acetylacetonate (Al ( CH7O2) 3). The aluminum precursor may also be advantageously an aluminum oxide or hydroxide.

The solution in which at least one surfactant, at least one polyoxometalate obtained according to step a) and at least one precursor of at least one Y element described above is mixed in accordance with step b) of said preparation process can advantageously be acidic, basic or neutral. Preferably, said solution is acidic or neutral. The acids used to obtain an acidic solution are advantageously chosen from hydrochloric acid, sulfuric acid and nitric acid. Said solution may advantageously be aqueous or may advantageously be a water-organic solvent mixture, the organic solvent being preferably a polar solvent, preferably an alcohol, and more preferably the solvent is ethanol. Said solution may also be advantageously substantially organic, preferably substantially alcoholic, the quantity of water being such that the hydrolysis of the inorganic precursors is ensured. The amount of water is therefore preferably stoichiometric. Very preferably, said solution is an acidic aqueous solution.

The surfactant used for the preparation of the mixture in step b) of said preparation process is an ionic or nonionic surfactant or a mixture of both. Preferably, the ionic surfactant is chosen from phosphonium and ammonium ions and very preferably from quaternary ammonium salts such as cetyltrimethylammonium bromide (CTAB). Preferably, the nonionic surfactant may be any copolymer having at least two parts of different polarities conferring properties of amphiphilic macromolecules. These copolymers may comprise at least one block that is part of the non-exhaustive list of the following families of polymers: fluorinated polymers (- [CH2-CH2-CH2-CH2-O-CO-R1- with R1 = C4F9, C $ F17, etc.), biological polymers such as polyamino acids (poly-lysine, alginates, etc.), dendrimers, polymers consisting of poly (alkylene oxide) chains. In general, any copolymer of amphiphilic nature known to those skilled in the art can be used (S. FSrster, M. Antionnetti, Adv Mater, 1998, 10, 195, S. Fdrster, T.Plantenberg, Angew Chem. Int.Ed., 2002, 41, 688, H. Cohen, Macromol Rapid Rapid, 2001, 22, 219). Preferably, a block copolymer consisting of poly (alkylene oxide) chains is used. Said block copolymer is preferably a block copolymer having two, three or four blocks, each block consisting of a poly (alkylene oxide) chain. For a two-block copolymer, one of the blocks consists of a poly (alkylene oxide) chain of hydrophilic nature and the other block consists of a poly (alkylene oxide) chain of a nature hydrophobic. For a copolymer with three blocks, at least one of the blocks consists of a chain of poly (alkylene oxide) hydrophilic nature while at least one of the other blocks consists of a poly ( alkylene oxide) of hydrophobic nature. Preferably, in the case of a three-block copolymer, the hydrophilic poly (alkylene oxide) chains are poly (ethylene oxide) chains denoted (PEO) X and (PEO) Z and the Poly (alkylene oxide) chains of hydrophobic nature are chains of poly (propylene oxide) denoted (PPO) y, poly (butylene oxide) chains, or mixed chains, each chain of which is a mixture of several alkylene oxide monomers. Very preferably, in the case of a three-block copolymer, there is used a compound of formula (PEO) X (PPO) y- (PEO) Z where x is between 5 and 300 and y is between 33 and 300 and z is between 5 and 300. Preferably, the values of x and z are the same. A compound is advantageously used in which x = 20, y = 70 and z = 20 (P123) and a compound in which x = 106, y = 70 and z = 106 (F127). Commercial nonionic surfactants known as Pluronic (BASF), Tetronic (BASF), Triton (Sigma), Tergitol (Union Carbide), Brij (Aldrich) are useful as nonionic surfactants. For a four-block copolymer, two of the blocks consist of a chain of poly (alkylene oxide) hydrophilic nature and the other two blocks consist of a chain of poly (oxides) of alkylene hydrophobic nature. Preferably, for the preparation of the mixture of step b) of said preparation process, the mixture of an ionic surfactant such as CTAB and a nonionic surfactant such as P123 is used.

The polyoxometalates described above and having the above general formula are used in step b) of the process for preparing said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls. The preferred polyoxometallates used according to the invention are advantageously chosen from polyoxometalates of formula: ## STR13 # Step c) of said preparation process consists of a ripening step, that is to say a stirring storage step of said colloidal solution obtained at the end of step b) at a temperature of between 25.degree. ° C and 80 ° C and preferably between 25 ° C and 40 ° C for a period between 1 h and 48 h and preferably between 20 h and 30 h. At the end of the curing step c), a suspension is obtained. The optional step d) of said preparation process consists of a possible autoclaving of the suspension obtained at the end of step c). This step consists of placing said suspension in a closed chamber at a temperature of between 80 ° C. and 140 ° C., preferably between 90 ° C. and 120 ° C. and more preferably between 100 ° C. and 110 ° C. to work in autogenous pressure inherent to the operating conditions chosen. The autoclaving is maintained for a period of between 12 and 48 hours and preferably between 15 and 30 hours. The suspension obtained at the end of step c) is then filtered according to step e) and the solid thus obtained is washed and dried. Washing said solid obtained after filtration and before drying is advantageously with a solution of the same nature as the solution used for mixing in accordance with step b) of said preparation process, and then with an aqueous solution of distilled water. The drying of said solid obtained after filtration and washing during step e) of said preparation process is advantageously carried out in an oven at a temperature of between 25 ° C. and 140 ° C., preferably between 25 ° C. and 100 ° C. and preferably between 30 and 80 ° C and for a period of between 10 and 48 h and preferably between 10 and 24 h. Step f) then consists of a step of removing said surfactant leading to the generation of the uniform and organized mesoporosity of the mesostructured matrix. The removal of the surfactant during step f) of said preparation process in order to obtain the mesostructured matrix used according to the invention is advantageously carried out by heat treatment and preferably by calcination in air at a temperature of between 300 ° C. and 1000 ° C and preferably at a temperature between 400 ° C and 600 ° C for a period of between 1 and 24 hours and preferably for a period of between 6 and 20 hours. Step f) is optionally followed by a step g) of treating the solid in order to regenerate at least partially or in full the polyoxometallate entity optionally at least partially or completely decomposed during step f). In the case where said polyoxometallate is completely decomposed during step f), said regeneration step g) is mandatory. This step advantageously consists in washing the solid with a polar solvent using a Soxhlet type extractor. Preferably, the extraction solvent is chosen from alcohols, acetonitrile and water. Preferably the solvent is an alcohol and very preferably the solvent is methanol. Said washing is carried out for a period of between 1 and 24 hours, and preferably between 1 and 8 hours at a temperature between 65 and 110 ° C and preferably between 90 and 100 ° C. Extraction with polar solvent not only allows to reform said polyoxometalates entrapped in the walls of said matrix but also to eliminate said polyoxometalates optionally formed on the surface of said matrix.

In the case where step g) is mandatory, said step g) is followed by step h). Step h) consists of a drying step of said solid thus obtained, said solid consisting of said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls. The drying of said solid is advantageously carried out in an oven or in an oven at a temperature of between 40 ° C. and 140 ° C., preferably between 40 ° C. and 100 ° C. and for a period of between 10 and 48 h. Said mesostructured oxide matrix comprising said polyoxometalates entrapped in its walls used in the process according to the invention advantageously has a specific surface area of between 100 and 1000 m 2 / g and very advantageously between 200 and 500 m 2 / g. Said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls, that is to say the catalyst in its oxide form, has a shape of each of the elementary particles constituting it, which is non-homogeneous, ie an irregular shape and preferably not spherical. Preferably, said elementary particles constituting said matrix comprising said polyoxometalates trapped in its walls are nonspherical. At the end of the so-called direct synthesis synthesis method, said elementary particles constituting said matrix comprising said polyoxometalates entrapped in its walls advantageously have a mean size of between 50 nm and 10 microns and preferably between 50 nm and 1 micron. Other elements may advantageously be added at different stages of the preparation of said mesostructured oxide matrix used in the invention. Said elements are preferably chosen from group VIII elements called promoters, doping elements and organic compounds. Very preferably, said group VIII metal is selected from nickel and cobalt and more preferably the group VIII metal consists solely of cobalt or nickel. Even more preferably, the Group VIII metal is cobalt. The doping elements are preferably chosen from boron, silicon, phosphorus and fluorine, taken alone or as a mixture.

Said elements may advantageously be added alone or in a mixture during one or more steps of the process for preparing said matrix chosen from the following steps i), ii), iii) and iv). i) Said elements may advantageously be introduced during step b) of the process for preparing said mixing matrix in solution of at least one surfactant, at least one silica precursor, at least one precursor of at least one Y element selected from the group consisting of silicon, aluminum, titanium, zirconium, gallium, and cerium and the mixture of at least one of these elements, then at least one polyoxometallate obtained according to step a) to obtain a colloidal solution. ii) Said elements may advantageously be introduced after step f) and before step g) of said preparation process. Said elements may advantageously be introduced by any technique known to those skilled in the art and advantageously by dry impregnation.

iii) Said elements may advantageously be introduced after step h) of drying said preparation process before shaping. Said elements may advantageously be introduced by any technique known to those skilled in the art and advantageously by dry impregnation.

iv) Said elements can advantageously be introduced after the shaping step of said matrix. Said elements may advantageously be introduced by any technique known to those skilled in the art and advantageously by dry impregnation.

After each of the steps ii) iii) or iv) described above, the solid obtained consisting of said mesostructured silicic oxide matrix comprising said polyoxometalates trapped in its walls may advantageously undergo a drying step and optionally an air enrichment calcination step optionally enriched at 02 at a temperature between 200 and 600 ° C and preferably between 300 and 500 ° C for a period of between 1 and 12 hours and preferably for a period of between 2 and 6 hours.

The sources of group VIII elements which can advantageously be used are well known to those skilled in the art. Nitrates preferably selected from cobalt nitrate and nickel nitrate, sulphates, hydroxides selected from cobalt hydroxides and nickel hydroxides, phosphates, halides selected from chlorides, bromides and fluorides, The carboxylates chosen from acetates and carbonates can advantageously be used as sources of group VIII elements.

The promoter elements of group VIII are advantageously present in the catalyst at contents of between 0.1 and 10% by weight, preferably between 1 and 7% by weight of oxide relative to the final catalyst. The doping elements that can advantageously be introduced are advantageously chosen from boron, silicon, phosphorus and fluorine, taken alone or as a mixture. The doping element is an added element, which in itself has no catalytic character but which increases the catalytic activity of the metal (rate). Said doping element may advantageously be introduced alone or as a mixture during the synthesis of said material used in the invention. It may also be introduced by impregnation of the material used according to the invention before or after drying, before or after reextraction. Finally, said dopant may be introduced by impregnation of said material used in the invention after shaping.

The doping elements are advantageously present in the catalyst used according to the present invention at contents of between 0.1 and 10% by weight and preferably between 0.1 and 5% by weight of oxide relative to the final catalyst. The boron source may advantageously be boric acid, preferably orthoboric acid H3BO3, ammonium diborate or pentaborate, boron oxide, boric esters. Boron may also be introduced together with the group VIB element (s) in the form of heteropolyanions of Keggin, Keggin lacunary, substituted Keggin such as for example in the form of boromolybdic acid and its salts, or borotungstic acid and its salts during the synthesis of said matrix. Boron, when it is not introduced during the synthesis of said matrix but in post-impregnation, may advantageously be introduced for example by a boric acid solution in a water / alcohol mixture or in a mixture of water and water. ethanolamine. Boron may also advantageously be introduced in the form of a mixture of boric acid, hydrogen peroxide and a basic organic compound containing nitrogen such as ammonia, primary and secondary amines, cyclic amines compounds of the family of pyridine and quinolines and compounds of the pyrrole family.

The phosphorus source may advantageously be orthophosphoric acid H 3 PO 4, the corresponding salts and esters or ammonium phosphates. Phosphorus can also advantageously be introduced at the same time as the group VIB element (s) in the form of heteropolyanions of Keggin, Keggin lacunary, substituted Keggin or Strandberg type such as, for example, in the form of acid. phosphomolybdic acid and its salts, phosphotungstic acid and its salts, during the synthesis of said matrix. Phosphorus, when not introduced during the synthesis of said matrix but post-impregnation, may advantageously be introduced in the form of a mixture of phosphoric acid and a basic organic compound containing nitrogen such as ammonia, primary and secondary amines, cyclic amines, pyridine family compounds and quinolines and compounds of the pyrrole family. The fluorine sources which can advantageously be used are well known to those skilled in the art. For example, the fluoride anions can be introduced in the form of hydrofluoric acid or its salts. These salts are formed with alkali metals, ammonium or an organic compound. In the latter case, the salt is advantageously formed in the reaction mixture by reaction between the organic compound and the hydrofluoric acid. The fluorine, when it is not introduced during the synthesis of said matrix but in post-impregnation, can advantageously be introduced for example by impregnation with an aqueous solution of hydrofluoric acid, or ammonium fluoride or else ammonium difluoride.

Once the doping element introduced by post-impregnation, the skilled person can advantageously proceed to a drying at a temperature advantageously between 90 and 150 ° C and for example at 120 ° C, and optionally then calcination so preferred under air in crossed bed, at a temperature advantageously between 300 and 700 ° C and for example 450 ° C for 4 hours.

The organic compounds are preferably chosen from chelating agents, non-chelating agents, reducing agents and additives known to those skilled in the art. Said organic compounds are advantageously chosen from optionally etherified mono-, di- or polyalcohols, carboxylic acids, sugars, non-cyclic mono-, di- or polysaccharides such as glucose, fructose, maltose, lactose or sucrose, esters, ethers, crown ethers, compounds containing sulfur or nitrogen such as nitriloacetic acid, ethylenediaminetetraacetic acid, or diethylenetriamine. Said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls and serving as catalyst support may be obtained in the form of powder, beads, pellets, granules or extrudates, the shaping operations being carried out according to conventional techniques known to those skilled in the art. Preferably, said mesostructured oxide matrix used according to the invention is obtained in powder form and shaped in the form of extrudates or beads.

During these shaping operations, it is also possible to add to said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls, at least one porous oxide material preferably selected from the group formed by alumina, silica, silica-alumina, magnesia, clay, titania, zirconium oxide, lanthanum oxide, cerium oxide, aluminum phosphates, boron phosphates, or a mixture thereof at least two of the oxides mentioned above and the alumina-boron oxide combinations, the alumina-titanium, alumina-zirconia and titanium-zirconia mixtures. It is also possible to add aluminates, such as, for example, aluminates of magnesium, calcium, barium, manganese, iron, cobalt, nickel, copper and zinc, mixed aluminates such as, for example those containing at least two of the metals mentioned above. It is also advantageously possible to add titanates, such as for example titanates of zinc, nickel or cobalt. It is also advantageously possible to use mixtures of alumina and silica and mixtures of alumina with other compounds such as, for example, Group VIB elements, phosphorus, fluorine or boron. It is also possible to use simple synthetic or natural clays of 2: 1 dioctahedral phyllosilicate or 3: 1 trioctahedral phyllosilicate type such as kaolinite, antigorite, chrysotile, montmorillonnite, beidellite, vermiculite, talc, hectorite, saponite, laponite. These clays can be optionally delaminated. It is also advantageously possible to use mixtures of alumina and clay and mixtures of silica-alumina and clay.

Said mesostructured oxide matrix comprising said polyoxometalates trapped in its walls is characterized by several analysis techniques and in particular by X-ray diffraction at low angles (low-angle XRD), X-ray diffraction at large angles (XRD), by volumetry with nitrogen (BET), transmission electron microscopy (TEM) optionally coupled to X analysis, scanning electron microscopy (SEM), X-ray fluorescence (FX) and any technique known to those skilled in the art for characterize the presence of polyoxometalates such as Raman spectroscopies in particular, UV-visible or infrared as well as microanalyses. Techniques such as nuclear magnetic resonance (NMR) or electronic paramagnetic resonance (EPR) (especially in the case of the use of reduced heteropolyanions), may also be used depending on the type of heteropolyanions used.

At the end of the preparation process described above, the catalyst is in its oxide form in the form of a solid consisting of a mesostructured oxide matrix comprising said polyoxometalates trapped in its walls. According to the invention, said catalyst, in its oxide form, is sulphurized before being used in the process according to the invention and in particular in the hydrotreatment stage and / or in the hydroisomerisation stage . This sulphurization step generates the active sulphide phase. Indeed, the transformation of at least one polyoxometallate trapped in the mesostructured oxide matrix into its associated sulphurated active phase is advantageously carried out by sulphidation, ie by a temperature treatment of said matrix in contact with an organic sulfur compound decomposable and H2S generator or directly in contact with a gas stream of H2S diluted in H2 at a temperature between 200 and 600 ° C and preferably between 300 and 500 ° C according to methods well known to man of career. More specifically, the sulfurization is carried out 1) in a unit of the process itself using the feedstock to be treated in the presence of hydrogen and hydrogen sulfide (H2S) introduced as such or from the decomposition of a organic sulfur compound, so-called in-situ sulfurization or 2) prior to the loading of the catalyst in the unit, this is called ex-situ sulfurization. In the case of ex situ sulfurization, gaseous mixtures can advantageously be used, such as the H2 / H2S or N2 / H2S mixtures. The catalyst in its oxide form may also advantageously be ex-situ sulphurized from liquid phase model compounds, the sulphurizing agent then being chosen from dimethyl disulphide (DMDS), dimethyl sulphide, n-butyl mercaptan and tertionyl polysulfide-type polysulfide compounds. these being diluted in an organic matrix composed of aromatic or alkyl molecules Before said sulfidation step, said catalyst in its oxide form consisting of a mesostructured oxide matrix comprising said polyoxometalates entrapped in its walls can advantageously be pretreated thermally by methods well known to those skilled in the art, preferably by calcination in air at a temperature between 300 and 1000 ° C and preferably a temperature between 500 to 600 ° C for a period of between 1 and 24 hours and preferably during a duration between 6 and 15 hours.

According to a preferred embodiment, the polyoxometallates trapped in the walls of said mesostructured oxide matrix may advantageously be partially or totally sulphurized at the time of the preparation process by direct synthesis of said mesostructured oxide matrix comprising said polyoxometalates used according to the invention and preferably during step b) of said preparation process, by introducing into the solution, in addition to at least one surfactant, at least one polyoxometalate and at least one precursor of the element Y, sulfur-containing precursors advantageously chosen from thiourea, thioacetamide, mercaptans, sulphides and disulphides. The decomposition at low temperature, that is to say at a temperature between 80 and 90 ° C of said sulfur precursors, either during step c) curing or during step d) autoclaving results in the formation of H2S thus allowing the sulfurization of said polyoxometalates. According to another preferred embodiment, the partial or total sulfurization of said polyoxometalates may advantageously be carried out by introducing said sulfur precursors in step g) of partial or total regeneration of said polyoxometalates entrapped in said mesostructured oxide matrix of the catalyst used in the invention. .

The invention is illustrated by means of the following examples.

Examples The following examples specify the invention without limiting its scope. EXAMPLE 1 (not in accordance with the invention): Preparation of a NiMoP NiMoP formulation hydrotreatment catalyst based on nickel, molybdenum and phosphorus deposited by dry impregnation of the alumina support of a solution containing the corresponding molecular precursors . Catalyst A of the hydrotreatment section is prepared from a transition alumina, in powder form, having specific surface textural properties, pore volume, and pore diameter of 290 m 2 / g, 0.7 ml / m 2, respectively. g, 9.4 nm (maximum data at desorption). Catalyst A is prepared by the method of dry impregnation of an aqueous solution prepared from ammonium heptamolybdate, nickel nitrate and orthophosphoric acid, the volume of the solution containing the precursors metals being strictly equal to the pore volume of the support mass. The precursor concentrations of the aqueous solution are adjusted so as to deposit on the support the desired weight contents. The catalyst is then dried for 12 hours at 120 ° C. and then calcined in air at 500 ° C. for 2 hours. The catalyst A thus obtained in the oxide state, of NiMoP formulation, has a molybdenum content of 21 expressed in% by weight. MoO3 oxide, a nickel content of 4.3 expressed by weight of oxide NiO and a phosphorus content of 0.86 expressed as% by weight of oxide P205. This catalyst is not in accordance with the invention. Catalyst A obtained was analyzed by Raman spectroscopy. No band characteristic of the presence of a heteropolyanion is detected.

EXAMPLE 2 (not in accordance with the invention): preparation of a NiwP-based hydroxide-isomerization catalyst B based on nickel, tungsten and phosphorus deposited by dry impregnation of a silica-alumina support with a solution containing the corresponding molecular precursors. Catalyst B of the hydroisomerization section is prepared by dry impregnation of a silica alumina support, commercial Siralox 30 comprising 30% by weight of silica in the final oxide support and having the following textural characteristics: 307 m 2 / g, , 59 ml / g, 7.6 nm (maximum data at desorption), using an aqueous solution containing the precursors ammonium metatungstate oxides, nickel nitrate and orthophosphoric acid according to the method described in EXAMPLE 1 After the drying and calcination steps as described in Example 1, the catalyst B thus obtained in the oxide state has a tungsten content of 27, expressed in% by weight of tungsten oxide, a nickel content of 3.5 expressed as% by weight of nickel oxide and a phosphorus content of 0.7 expressed as% by weight of phosphorus oxide. This catalyst is not in accordance with the invention. The catalyst B obtained was analyzed by Raman spectroscopy. No band characteristic of the presence of a heteropolyanion is detected.

Example 3 (in accordance with the invention): preparation of a hydrotreatment catalyst C of NiMoP formulation comprising the Ke-in hetero-ol acid of formula PMo1O403-3H + trapped in a mesostructured silica matrix of SBA-type The mesostructured silicic matrix SBA-15 comprising the Keggin heteropolyacid of formula PMo120403 3H + trapped in its walls is obtained by direct synthesis according to the following preparation method: the Keggin heteropolyacid of formula PMot2040 3H + is purchased from Aldrich. 0.1 g of cetyltrimethylammonium bromide surfactant (CTAB) and 2.0 g of Pluronic P123 surfactant (PE020PP07OPE020) are dissolved in 62.5 g of a 1.9 mol / l hydrochloric acid solution. 4.1 g of tetraethylorthosilicate (TEOS) silica precursor of formula Si (OEt) 4 are then added, then the medium is stirred for 45 min. 0.352 g of the Keggin heteropolyacid of formula PMo12O403 ", 3H + in 10 g of the same hydrochloric acid solution are then added, The resulting colloidal solution is then left stirring for 20 hours at 40 ° C. The suspension is decanted in a teflonated autoclave for treatment at a temperature of 100 ° C. for 24 hours, the suspension thus obtained is then filtered and the solid, after washing with 30 ml of the 1.9 mol / l hydrochloric acid solution and 60 ml. ml of distilled water is dried overnight in an oven at 40 ° C. The solid obtained is then calcined at a plateau temperature of 490 ° C. for 19 hours so as to eliminate the surfactants and to release the mesoporosity of said solid. The solid obtained is then introduced into a Soxhlet-type extractor and the system is refluxed in the presence of methanol for 4 hours so as to regenerate the heteropolyanion decomposed during the calcination step. The solid is then dried to remove the solvent at a temperature of 90 ° C for 12 hours. The solid obtained constituted by the mesostructured silicic matrix SBA-15 comprising the Keggin heteropolyacid of formula PMo12O403 ", 3H + trapped in its walls is then dry impregnated with a solution of nickel nitrate and then dried at 120 ° C. for 12 hours to The final contents expressed in% by weight of oxides NiO, MoO3 and P2O5 are respectively 4.2 / 20.9 / 0.85 relative to the final solid.Catalyst C has textural properties (specific surface porous volume, pore diameter) respectively (340 m 2 / g, 0.9 ml / g, 7.5 nm) The catalyst C obtained was analyzed by Raman spectroscopy and reveals the characteristic bands of the heteropoly acid of Keggin of formula PM012O403 3H + at 992, 973, 895 and 605 cc Example 4 (in accordance with the invention): preparation of a hydroxylisomerization catalyst D of NiWP formulation containing the hetero-ol acid of Ke-- in formula PW1 O40 + 3H or phosphotunqstic acid entrapped in a Mesostructured aluminosilicic matrix of Si / Al molar ratio = 10. 0.1 g of CTAB and 2.0 g of P123 are dissolved in 62.5 g of a 1.9 mol / l aqueous hydrochloric acid solution. 3.71 g of TEOS and 0.44 g of Al (OtBu) 3 are then added, then the medium is stirred for 45 min. 0.464 g of the Keggin heteropoly acid of formula PW12O403 3H + from Aldrich in 10 g of the same hydrochloric acid solution are then added.

The colloidal solution obtained is then left stirring for 20 hours at 40 ° C. The suspension is decanted into a Teflon autoclave for treatment at a temperature of 100 ° C for 24 hours. The suspension thus obtained is then filtered and the solid, after washing with 30 ml of the 1.9 mol / l hydrochloric acid solution and 60 ml of distilled water, is dried overnight in an oven at 40 ° C. . The solid obtained is then calcined at a plateau temperature of 490 ° C. for 19 hours so as to eliminate the surfactants and to release the mesoporosity of said solid. The solid obtained is then introduced into a Soxhlet-type extractor and the system is refluxed in the presence of methanol for 4 hours so as to completely regenerate the decomposed heteropolyanion during the calcination step. The solid is then dried to remove the solvent at a temperature of 90 ° C for 12 hours. The resulting solid consisting of the mesostructured aluminosilicic matrix comprising the Keggin heteropolyanion of formula PW12O403 ", 3H + trapped in its walls is then dry impregnated with a solution of nickel nitrate and then dried at 120 ° C. for 12 hours to evacuate the The final contents, expressed as% by weight of oxides NiO, WO3 and P2O5, are respectively 3.5 / 26.7 / 0.69 relative to the final solid.Catalyst D has textural properties (specific surface, porous volume pore diameter) respectively (303 m 2 / g, 1 ml / g, 9 nm) The catalyst obtained was analyzed by Raman spectroscopy, it reveals bands at 1004 and 990 cm -1, as well as the secondary bands. 518 and 216 cm "characteristics of the Keggin heteropolyanion of formula PW12O403 3H + in agreement with the previous results published by B. Qiu, X. Yi, Lin L., W. Fang and H. Wan in Catalysis Today, 2008, 131, 1-4, 2008, 464.

The catalysts A, B, C, D obtained in Examples 1, 2, 3, 4 are in the form of a powder. In order to test these catalysts, they are previously shaped. For each example, the powders obtained are pelletized and then crushed. The catalysts are then in the form of particles having a particle size of between 1 and 2 mm. The set of characteristics of the catalysts A, B, C and D shaped is reported in Table 1.

Table 1. Main characteristics of catalysts prepared. Catalyst A g Formed CD Non-conforming Non-conforming Compliant Compliant Support Alumina Silica-alumina Silica Silica-mesostructured mesostructured alumina Method of impregnation impregnation of 3 3 preparation heptamolybdate metatungstate PMo12O40-, 3H PW12O40, 3H ammonium, d ammonium, trapped + post trapped + post nickel nitrate and nickel nitrate and impregnation impregnation impregnation of orthophosphoric Ni Ni acid orthophosphoric phase active phase NiMoP NiWP NiMoP NiWP MoO3 or WO3 21 27 20.9 26.7 (% wt) NiO (% wt) 4.3 3.5 4.2 3.5 P2O5 (wt%) 0.86 0.7 0.85 0.69 SBET (m2 / g) * 240 210 340 303 Volume 0, 57 0.4 0.9 porous total (ml / g) * Diameters of 9.5 8 7.5 9 average pores (nm) * * Value determined from the nitrogen adsorption / desorption isotherm Example 5 Comparison of the Performance of Catalysts A and C in Hydroprocessing of a Rapeseed Oil The performances of the catalysts A and C, obtained respectively according to Examples 1 and 3, are compared for the hydrotreatment of a rapeseed oil. The rapeseed oil is processed in a fixed bed isothermal unit of the downflow type. The reactor is charged with 100 ml of hydrotreatment catalyst (catalyst loaded in the form of crushed elements with a particle size of between 1 and 2 mm). The catalysts are evaluated in their sulphide form and are sulphurized in situ prior to the test, using a diesel fuel feedstock (resulting from a direct distillation of the oil) additive of 2% by weight of dimethyl disulphide (DMDS). Sulfurization is carried out at 350 ° C. under a pressure of 5 MPa. Once the sulphurization is complete, the feedstock consisting of pre-refined rapeseed oil (density equal to 920 kg / m3, sulfur content of less than 10 ppm by weight and cetane number equal to 35) with a weight of 50 ppm by weight is introduced. sulfur in the form of DMDS, at a volume flow rate of 100 ml / h. Addition of the charge by the DMDS makes it possible to generate a partial pressure of H2S (resulting from the decomposition of the DMDS under the test conditions) sufficient to maintain the catalyst in the sulphide state. During the test, 700 Nm3 of hydrogen per m 3 of feed are introduced into the reactor maintained at a temperature of 270 ° C and a pressure of 5 MPa and a hourly space velocity of 1 h "".

The main characteristics of the colza oil feed used are shown in Table 2. Table 2. Characteristics of rapeseed oil. Charge Value Properties Elemental Analysis 4 S [ppm wt] N [ppm wt] 23 P [ppm wt] 177 C [% wt] 77.2 H [wt%] 11.6 O [wt%] 11.2 Composition Fatty acid (%) 14: 0 0.1 16: 0 5, 0 16: 1 0.3 17: 0 0.1 17: 1 0.1 18: 0 1.5 18: 1 trans <0.1 18: 1 cis 60.1 18: 2 trans <0.1 18: 2 cis 20.4 18: 3 trans <0.1 18: 3 cis 9.6 20: 0 0, 5 20: 1 1.2 22 : 0 0.3 22: 1 0.2 24: 0 0.1 24: 1 0, 2 44 The hydrotreatment of rapeseed oil leads to the majority production of linear paraffins in terms of chain length between tetradecane (C14) and tetracosane (C24). Also note the formation of compounds such as light hydrocarbons (C1 to C3), carbon oxides (CO and CO2) and water.

Table 3 shows the yields obtained in paraffins in the presence of catalyst A and C. These results show that the encapsulation of the NiMoP active phase in the form of heteropolyanions in the oxide state (catalyst C) makes it possible to to obtain a catalyst that is more active than the molybdenum-containing catalyst A. Table 3. Catalytic Performance of Catalysts A and C for the Hydroprocessing of a Rapeseed Oil. Catalysts AC (non-compliant) (compliant) Operating conditions Temperature [° C] 270 270 Pressure [MPa] 5 5 H2 / load [Nm3 / m3] 700 700 Results Conversion of load [% wt] 90.6 95.1 Yield paraffins C14 to C24 [% wt] 78.8 82.7 * Value obtained on the organic oxygenated fraction (excluding water and oxides of carbon) Example 6: Comparison of the performance of catalysts B and D for the hydroxisomerization of paraffins lonques obtained by hydrotreating rapeseed oil in the presence of the hydrotreatment catalyst A. The hydrocarbon base (C14 to C24) obtained in Example 5 in the presence of the non-conforming hydrotreatment catalyst A is hydroisomerized with hydrogen lost in a reaction reactor. hydroisomerization under the operating conditions below, in the presence of catalysts B or D (catalyst loaded in the form of crushed elements with a particle size of between 1 and 2 mm): VVH (volume of charge / volume of catalyst / hour) = 1 h "1, total pressure of tra vail: 5 MPa, hydrogen ratio / charge: 700 normal liters / liter. The crude conversion is defined as the conversion of the C15 + linear paraffins obtained in the first hydrotreatment stage into C15- and isomerized linear paraffins. The yield of middle distillates is equal to the weight of compounds having a boiling point above 150 ° C. The temperatures used to evaluate the catalysts B and D are set so as to obtain an identical crude conversion of 950% by weight. All the results obtained are reported in Table 4.

It appears that the catalyst D according to the invention comprising an active phase in the form of heteropolyanions trapped in the walls of a mesostructured oxide matrix is more active than the catalyst B not according to the invention since it makes it possible to obtain a crude conversion identical to catalyst B for a reaction temperature lower than 5 ° C. In addition, for a crude conversion of 950 wt.%, The catalyst D according to the invention leads to the production in greater quantity of a middle distillate cutter having excellent characteristics for use as a fuel base for middle distillates.

Table 4. Catalytic performance of catalysts B and D for the hydroisomerization of long paraffins. Catalysts B (non-compliant) D (compliant) Operating conditions Temperature [° C] 345 340 Pressure [MPa] 5 5 H2 / load [Nm3 / m3] 700 700 Results Gross conversion [% wt] 95 95 Average distillate yield 80 85 (150 ° C + cut) [% wt]

Claims (12)

REVENDICATIONS1. Process for the production of middle distillates from at least one feedstock from renewable sources comprising at least one hydrotreating step a) in which at least said feedstock is brought into contact with at least one hydrotreatment catalyst at a temperature of between 120 and 450 ° C., at a pressure of between 1 and 10 MPa, at a space velocity of between 0.1 and 10 h "and in the presence of a hydrogen / charge ratio of between 50 and 3000 Nm 3 of hydrogen / m3 of filler and at least one hydroisomerization step b) in which the effluent from step a) is brought into contact with at least one hydroisomerization catalyst at a temperature of between 120 and 450 ° C, at a pressure of between 1 and 10 MPa, at a space velocity of between 0.1 and 10 h -1 and in the presence of a hydrogen / charge ratio of between 50 and 3000 Nm 3 of hydrogen / m 3 of feedstock, hydrotreatment step and / or said hydroisom step process comprising a catalyst comprising, in its oxide form, at least one Group VIB metal and / or at least one Group VIII metal of the Periodic Table present in the form of at least one polyoxometalate of the formula (HhXXMmOy) qin which X is an element chosen from phosphorus (P), silicon (Si), boron (B), nickel (Ni) and cobalt (Co), said element being taken alone, M is one or more element (s) ) selected from molybdenum (Mo), tungsten (W), nickel (Ni) and cobalt (Co), where O is oxygen, h being an integer from 0 to 12, where x is an integer between 0 and 4, where m is an integer of 5, 6, 7, 8, 9, 10, 11, 12 and 18, where y is an integer of 17 to 72 and q is an integer of 1 to 20, said polyoxometalates being present in a mesostructured matrix based on an oxide of at least one Y element selected from the group consisting of silicon, aluminum, titanium and zirc onium, gallium, and cerium and the mixture of at least one of these elements, said matrix having a pore size of between 1.5 and 50 nm and having amorphous walls with a thickness of between 1 and 30 nm, said catalyst being sulfided before being used in said process. 2. Method according to claim 1 wherein said filler is selected from oils and fats of plant or animal origin, or mixtures of such fillers, containing triglycerides and / or free fatty acids and / or esters, the vegetable oils which may be raw or refined, wholly or in part, and derived from plants selected from rapeseed, sunflower, soya, palm, palm kernel, olive, coconut, jatropha, taken alone or in combination with mixed. 3. Method according to one of claims 1 or 2 wherein the polyoxometalates are the compounds corresponding to the formula (HhXXMn, Oy) q "wherein h is an integer between 0 and 6, x being an integer that may be equal to 0, 1 or 2, where m is an integer of 5, 6, 7, 9, 10, 11 and 12, where y is an integer of 17 to 48 and q is an integer of 3 to 12, X, M and O having the above meaning. 4. Method according to one of claims 1 to 3 wherein the polyoxometalates used are selected from polyoxometallates of formula H2W12O406 ", PMo12O403", PW12O403, HPNiMo11O406 ", P2Mo5O236 MM06O24H64-and Ni2Mo10O38H48 alone or in mixture. 5. Method according to one of claims 1 to 4 wherein the polyoxometalates are so-called Keggin heteropolyanions of general formula XM12O40q "for which the ratio m / x is equal to 12 and heteropolyanions said Keggin lacunar of general formula XM11O39q" for which the ratio m / x is equal to 11 and in which the elements X and M and the load q have the abovementioned meaning. 6. The method of claim 5 wherein the Keggin heteropolyanions are selected from heteropolyanions of formula PMo12O403 "and PW12O403" alone or in mixture. 7. Method according to one of claims 1 to 6 wherein the catalyst comprises a total mass content of Group VIB element expressed as a percentage by weight of oxide relative to the total mass of the catalyst between 2 and 35% by weight. 8. Method according to one of claims 1 to 7 wherein the catalyst comprises a mass content of the group VIII element expressed as a percentage by weight of oxide relative to the total mass of the catalyst between 0.1 and 10% weight. 9. Method according to one of claims 1 to 8 wherein the catalyst comprises a mass content of doping element selected from phosphorus, boron and silicon expressed as a percentage by weight of oxide relative to the total mass of the catalyst between 0.1 and 10% by weight. 10. Method according to one of claims 1 to 9 wherein said process is carried out in two stages, the hydrotreating step and the hydroisomerization step being carried out in two separate reactors and the step of hydrotreatment using a catalyst comprising a mesostructured matrix consisting of silicon oxide and the hydroisomerization step employing a catalyst comprising a mesostructured matrix comprising a mixture of silicon oxide and aluminum oxide. 11. Method according to one of claims 1 to 9 wherein said process is carried out in a single step, the hydrotreating step and the hydroisomerization step being carried out in a single reactor and said steps of hydrotreating and hydroisomerization being carried out in the presence of a single catalyst comprising a mesostructured matrix consisting of silicon oxide. 12. Method according to one of claims 1 to 11 wherein said catalyst in its oxide form has a shape of each of the non-spherical constituent elementary particles.