Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
  • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
  • C01B39/20—Faujasite type, e.g. type X or Y
  • C01B39/24—Type Y
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
  • C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
  • C01B39/04—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof using at least one organic template directing agent, e.g. an ionic quaternary ammonium compound or an aminated compound
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2002/00—Crystal-structural characteristics
  • C01P2002/20—Two-dimensional structures
  • C01P2002/22—Two-dimensional structures layered hydroxide-type, e.g. of the hydrotalcite-type
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/12—Surface area
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/14—Pore volume
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/16—Pore diameter
  • C01P2006/17—Pore diameter distribution

Definitions

• the present invention relates to the field of zeolites, more particularly zeolites with hierarchical porosity, and in particular zeolites with hierarchical porosity (ZPH) of faujasite structure (FAU) with an atomic ratio Si / Al strictly greater than 1, 4, in particular zeolites of type Y, hereinafter referred to as YPH.
• ZPH hierarchical porosity
• FAU faujasite structure
• Synthetic zeolites (that is to say non-natural) are of ever increasing interest in the industry, as evidenced by the many recent research work related to obtaining zeolites always more efficient, with synthetic processes always simpler, economic and easy to implement.
• hierarchical porosity zeolites are the subject of many scientific publications and patent applications.
• the process for synthesizing zeolites with hierarchical porosity with good crystallinity was described in application WO2007 / 043731, using an organosilane structuring agent.
• the product obtained after calcination comprises a zeolite network connected to a network of mesopores of a few nanometers in diameter.
• the hydrothermal resistance of this product is much better than that of mesoporous solids MCM 41 which allows to consider applications in which a thermal regeneration occurs.
• Post-treatment of zeolitic structures that consists of removing atoms from the zeolite network to create mesopores; this can be achieved either by acid treatments which dealuminate the solid followed by a washing with sodium hydroxide which eliminates the aluminic residues formed (J. Pérez-Ramirez et al., Adv Funct Mater., (2012), p 1 - 12) or by treatments that combine the action of an acid with that of a structuring agent that promotes the formation of mesopores (see WO 2013/106816).
• Hard templating method or “method of molding” which consists in using a porous network (organic or inorganic) as a mold, this porous network is put into contact with a reaction medium capable of forming a zeolite network by hydrothermal transformation, crystallization of the zeolite is carried out and then the mold is removed either by calcination or by dissolution to generate the mesoporosity (CJH Jacobsen, J. Am. C em. Soc., ( 2000), 122, 71 16-71 17).
• microporous volume of these hierarchically porous zeolites is significantly lower than that of non-mesoporous zeolites
• the structuring agent modifies the growth rates of the faces of the crystals, which makes it difficult to control the size of the crystals,
• One of the objectives of the present invention is to solve at least these three major drawbacks noted for direct synthesis using an organosilane type structuring agent.
• the patent application EP2592049 proposes a zeolite synthesis having a very large and well organized mesoporosity, but with a marked degradation of the crystalline framework (very low microporosity). This method uses a specific structuring agent comprising three ammonium functions.
• microporous volumes are significantly lower than the microporous volumes of equivalent non mesoporous zeolites (that is to say whose mesoporous outer surface as defined below is strictly less than 40. m 2, g "1 ), which is very penalizing in applications where a high active site content is required.
• m 2, g "1 equivalent non mesoporous zeolites
• the size of the crystals is undergone and can not be modified.
• the post-treatment is carried out by introducing an amount of Pluronic ® (nonionic surfactant) of the same order of magnitude (similar amount by weight) the amount of Y zeolite, then by long treatments, in liquid way, followed by several calcination treatments.
• Pluronic ® nonionic surfactant
• WO2012 / 084276 describes a method for preparing a mesoporous Y zeolite by various basic post-treatments but at the expense of microporosity. These treatments also lead, as claimed, to an increase in the Si / Al atomic ratio by dealumination. Although these methods make it possible to prepare zeolites with hierarchical porosity, as shown by the shape of the nitrogen adsorption isotherms of the solids obtained, it is important to note that these processes use quantities of post-treatment fluids. of the same order of magnitude as the initial zeolite mass with multiple and long operations. In addition, the mass yield of these processes is less than 60% which further penalizes their productivity. These processes are therefore long, expensive and unproductive.
• an object of the present invention is to provide Y-type FAU zeolites with hierarchical porosity combining mesoporosity, high microporous volume, optimal purity and adjustable crystal sizes, and Si / Al atomic ratio strictly greater than 1, 4.
• Another object of the present invention is to provide an economical, simple and easily industrializable process for the preparation of said zeolites.
• Y type mesoporous FAU zeolites by direct route, that is to say without going through the synthesis of a type Y FAU zeolite which would then undergo a or several post-treatments necessary according to the prior art to obtain a certain mesoporosity.
• Y-type FAU zeolites with hierarchical porosity (YPH) according to the invention have quite interesting characteristics and are thus easily industrialized by a direct route.
• the present invention relates to a zeolite with hierarchical porosity having the following characteristics:
• Si / Al atomic ratio strictly greater than 1, 4 and less than 6, preferably between 1, 5 and 5 inclusive, more preferably between 1, 5 and 3 inclusive,
• Microporous volume ⁇ , in cm 3 . g "1 , corresponding to the equation ⁇ ⁇ ⁇ ⁇ ⁇ 15%, where ⁇ / ⁇ ! represents the microporous volume, in cm 3 .g -1 , measured under the same conditions, for a zeolite of the same chemical nature and same structure crystalline, but whose mesoporous outer surface is strictly less than 40 m 2 .g -1 , and
• Mesoporosity such that the mesoporous outer surface is between 40 m 2 . g "1 and 400 m 2, g " 1 , preferably between 60 m 2 . g “1 and 200 m 2. g" 1 and more preferably between 60 m 2 ⁇ g "1 and 150 m 2 .g" 1.
• the zeolite according to the present invention is a zeolite of the FAU type, and in particular a zeolite FAU type Y.
• the zeolite with hierarchical porosity has a mean diameter in number of crystals between 0.1 ⁇ and 20 ⁇ , preferably between 0.1 ⁇ and ⁇ ⁇ ⁇ , more preferably between 0.5 ⁇ and 10 ⁇ , more preferably between 0.5 ⁇ and 5 ⁇ , limits included.
• the size of the zeolite crystals according to the present invention is expressed by their number average diameter by observation with a scanning electron microscope (SEM), as indicated below.
• SEM scanning electron microscope
• the present invention also has the advantage of allowing to adjust and adjust this size of crystals, in particular according to the synthesis conditions explained below.
• the hierarchically porous zeolite of the present invention furthermore has a controlled crystallinity, which means that the zeolite comprises a pure zeolitic phase, and more precisely constituted by a single zeolite phase or comprising, preferably consisting of, up to 2% by weight, inclusive, of one or more other zeolitic or amorphous phases, called polluting phases (crystallinity determined by XRD, technique described below).
• a controlled crystallinity means that the zeolite comprises a pure zeolitic phase, and more precisely constituted by a single zeolite phase or comprising, preferably consisting of, up to 2% by weight, inclusive, of one or more other zeolitic or amorphous phases, called polluting phases (crystallinity determined by XRD, technique described below).
• zeolite of the same chemical nature and of the same crystalline structure but not perfectly crystalline mesoporous within the meaning of the invention is meant a zeolite prepared in the same conditions, but for which no specific treatment has been employed to create a mesoporosity, either directly (using a structuring agent as described later in the present invention) and / or by post-treatment.
• the zeolites with hierarchical porosity according to the invention make it possible to reconcile the properties of accessibility to the active sites of the mesoporous zeolites known from the prior art and those of crystallinity and maximum microporosity of the so-called "classical" zeolites (without mesoporosity). .
• the hierarchically porous zeolites of the present invention have unexpected properties and open new perspectives as to their fields of industrial applications.
• the zeolites of the present invention may be subjected to one or more cationic exchanges (for example with alkali metal or alkaline earth metal salt (s)) as is well known to those skilled in the art and commonly performed on conventional zeolites.
• cationic exchanges for example with alkali metal or alkaline earth metal salt (s)
• the present invention relates to the method for preparing zeolites with hierarchical porosity as just described.
• the method of the invention has the advantages of being easy to implement, easily transferable on an industrial scale, and this in particular because of the high yields of synthetic materials, the robustness of the process and its speed.
• the method for preparing the zeolite with hierarchical porosity comprises at least the following steps: a) preparing a so-called growth gel for the preparation of a Y-type FAU zeolite, by mixing a source of silica with a source of alumina, at a temperature between 0 ° C and 60 ° C,
• step b) adding to the growth gel of step a) at least one nucleating agent, at a temperature between 0 ° C and 60 ° C,
• step a) The growth gel used in step a) is well known to those skilled in the art and is perfectly defined for example in DW Breck ("Zeolite Molecular Sieves", John Wiley and Sons, New York, (1973) , pp. 277 ff.).
• step c) of adding agent (s) structurant (s) can be operated at the same time as steps a) and / or b) or before and / or after the steps a) and / or b).
• the structuring agent must be present in the reaction medium before step d) of crystallization.
• a latency time rest time, with or without agitation
• steps a), b), c) and d can be provided between steps a), b), c) and d).
• the process of the present invention is characterized by the use of the seeding technique with at least one nucleating agent well known to those skilled in the art, for example selected from a nucleating gel, a crystal, by for example, a zeolite crystal, a mineral particle of any kind, for example kaolin, meia-kaolin, or other clay, and the like, and mixtures thereof.
• a nucleating agent well known to those skilled in the art, for example selected from a nucleating gel, a crystal, by for example, a zeolite crystal, a mineral particle of any kind, for example kaolin, meia-kaolin, or other clay, and the like, and mixtures thereof.
• the nucleating agent promotes the orientation of the synthesis to the desired zeolite.
• the nucleating agent is a nucleation gel, and more preferably, said nucleating gel comprises a homogeneous mixture of a source of silica (for example sodium silicate), a source of alumina (for example alumina trihydrate), a strong mineral base, such as, for example, sodium hydroxide, potassium hydroxide, or calcium hydroxide to name only the main and most commonly used, and water.
• a source of silica for example sodium silicate
• a source of alumina for example alumina trihydrate
• a strong mineral base such as, for example, sodium hydroxide, potassium hydroxide, or calcium hydroxide to name only the main and most commonly used, and water.
• the growth gel comprises a homogeneous mixture of a source of silica (for example sodium silicate or colloidal silica, preferably colloidal silica), a source of alumina (for example example alumina trihydrate), a strong mineral base, such as, for example, sodium hydroxide, potassium hydroxide, or calcium hydroxide to name only the main and most commonly used, and water.
• a source of silica for example sodium silicate or colloidal silica, preferably colloidal silica
• a source of alumina for example alumina trihydrate
• a strong mineral base such as, for example, sodium hydroxide, potassium hydroxide, or calcium hydroxide to name only the main and most commonly used, and water.
• the homogeneity of the mixture can be obtained by any method well known to those skilled in the art, and for example and without limitation by means of a paddle stirrer, a mixer, or to using an Archimedean screw type mixer as described in patent EP0818418. Agitators with a high shear rate, for example of the mixer type, are preferred.
• the mixture is generally prepared at temperatures between 0 ° C and 60 ° C, preferably between 10 ° C and 40 ° C, and for practical and economic reasons, the mixture is prepared at room temperature, for example at 25 ° C.
• the homogenization period is then less than 2 hours.
• the process of the present invention is further characterized by adding to the growth gel thus obtained at least one nucleating agent, and preferably a nucleating gel, according to the concept defined in the patent.
• the amount of nucleation gel added can vary in large proportions but is generally between 0.1% and 20%, preferably between 0.5% and 15% by weight, more preferably between 1% and 10% by weight. , limits included, relative to the weight of the growth gel.
• the nucleating agent is a zeolite crystal
• it is preferably a zeolite crystal of the same nature as the zeolite that it is desired to synthesize.
• the size of the crystal can vary in large proportions, and for example is typically between 0.1 ⁇ and 10 ⁇ .
• the zeolite crystal is introduced in the form of an aqueous suspension.
• the amount of crystals introduced may also vary in large proportions, but this amount of crystals is generally between 0.1% and 10% by weight relative to the total weight of growth gel.
• the process of the present invention is a method of direct synthesis of zeolite with hierarchical porosity, and not a process where the hierarchical porosity results from a post-treatment of an already synthesized zeolite.
• the method of the present invention comprises an addition step in the mixture [growth gel / nucleating agent] obtained in step b) of at least one structuring agent.
• the structuring agent is advantageously chosen from organosilanes and more preferably from [3- (trimethoxysilyl) propyl] octadecyldimethylammonium chloride, [3- (trimethoxysilyl) propyl] hexadecyldimethylammonium chloride, [3- (trimethoxysilyl) propyl] dodecyldimethylammonium chloride, [3- (trimethoxysilyl) propyl] octylammonium chloride, N- [3- (trimethoxysilyl) propyl] aniline, 3- [2- (2-aminoethylamino) ) ethylamino] propyltrimethoxysilane, N- [3- (trimethoxysilyl)
• PPDA Polymer Poly-Diallyldimethylammonium
• PVB PolyVinyl Butyral
• other oligomeric compounds known in the art for increasing the diameter of the mesopores.
• agent (s) structurant (s) can vary in large proportions and in general it is such that the molar ratio agent (s) structurant (s) / AI 2 0 3 starting is understood between 0.005 and 0.20, preferably between 0.01 and 0.15, more preferably between 0.02 and 0.08 inclusive.
• step a The addition of the structuring agent (s) is carried out with stirring, for example as indicated previously in step a), and then the mixture is subjected to a maturation step, preferably with stirring, always at the same temperature, for example at 25 ° C, for a time varying from a few minutes to several tens of minutes, typically for one hour, with stirring at 300 rpm "1 .
• step d) of crystallization the reaction mixture is engaged in step d) of crystallization, still with stirring, but slower, typically between 20 and 100 rpm " , for example at 50 rpm " 1 , and increasing the temperature to a value between 60 ° C and 100 ° C, for example 75 ° C.
• the time required for crystallization is generally between a few hours and several tens of hours, advantageously between 8 hours and 48 hours.
• the zeolite crystals are extracted from the reaction medium by filtration, and then washed with one or more suitable solvent (s), aqueous and / or organic (s), but preferably aqueous and finally dried between 50 and 150 ° C, according to the usual techniques known to those skilled in the art.
• the average size of the crystals may in particular be controlled by adjusting the content of nucleating agent (nucleation gel, or crystals, for example zeolite, or other) relative to the growth gel during step b).
• nucleating agent nucleation gel, or crystals, for example zeolite, or other
• the dried crystals are then subjected to calcination, a step necessary to release both the microporosity (elimination of water) and the mesoporosity (elimination of the structuring agent).
• the calcination used to eliminate the structuring agent can be carried out according to any calcination method known to those skilled in the art.
• the calcination of the zeolite crystals comprising the structuring agent can be carried out under an oxidizing and / or inert gas scavenging, with in particular gases such as oxygen, nitrogen, air, a dry air and / or decarbonated oxygen depleted air, optionally dry and / or decarbonated, at a temperature or temperatures above 150 ° C, typically between 180 ° C and 800 ° C, preferably between 200 ° C and 650 ° C ° C, for a few hours, for example between 2 and 6 hours.
• gases such as oxygen, nitrogen, air, a dry air and / or decarbonated oxygen depleted air, optionally dry and / or decarbonated
• a temperature or temperatures above 150 ° C typically between 180 ° C and 800 ° C, preferably between 200 ° C and 650 ° C ° C, for a few hours, for example between 2 and 6 hours.
• gases such as oxygen, nitrogen, air, a dry air and / or decarbonated oxygen de
• cationic exchanges for example with alkali metal or alkaline earth metal salt (s)
• drying step and / or calcination (step f) it would not be outside the scope of the invention by operating one or more cationic exchanges (for example with alkali metal or alkaline earth metal salt (s)), before or after the drying step and / or calcination (step f)), according to conventional cation exchange techniques.
• the synthesis method of the invention is easy to implement and it is performed in a relatively short time, and in particular in a reduced time by a factor of at least 4, with respect to synthesis processes of Hierarchized Porosity Zeolites (ZPH) known from the prior art which are very long due to the inhibitory effect of the organosilane structurant for nucleation and growth of the microporous zeolite network. It has been discovered, quite surprisingly, that the inhibitory effect of the structuring agent (eg TPOAC) is compensated for by the presence of the nucleating agent.
• ZPH Hierarchized Porosity Zeolites
• Meng (ibid.) Shows that an increase in the content of the structuring agent, which should lead to an increase in the mesoporous volume, also has the effect of modifying the growth rates of the zeolite network, thus causing the appearance of other zeolitic crystalline phases and thus the formation of mixtures of zeolitic structures, which is not desired).
• the process of the invention is more productive and less expensive because it is carried out in a single step, of relatively short duration. (less than one day) with a low amount of structuring agent, and therefore globally with a relatively low cost, or at least with a limited additional cost compared to that of a non-mesoporous zeolite synthesis, and much lower than the cost induced by methods of synthesis of ZPH by post-treatment.
• the loss on ignition is determined in an oxidizing atmosphere, by calcination of the sample in air at a temperature of 950 ° C ⁇ 25 ° C, as described in standard NF EN 196-2 (April 2006). The standard deviation of measurement is less than 0.1%.
• the volume of Dubinin-Raduskevich is determined from the measurement of the nitrogen adsorption isotherm at its liquefaction temperature. Prior to adsorption, the zeolite adsorbent is degassed between 300 ° C. and 450 ° C. for a period of between 9 hours and 16 hours under vacuum (P ⁇ 6.7 ⁇ 10 -4 Pa). adsorption is then carried out on an ASAP 2020 Micromeritics-type apparatus, taking at least 35 measuring points at relative pressures of ⁇ / ⁇ 0 ratio of between 0.002 and 1.
• microporous volume is determined according to Dubinin and Rohskevitch from isotherm obtained by applying the ISO 15901 -3 (2007) standard
• the microporous volume evaluated according to the Dubinin and Rohskevitch equation is expressed in cm 3 of liquid adsorbate per gram of zeolite The measurement uncertainty is ⁇ 0.003 cm 3 g -1 .
• the estimation of the average number diameter of the zeolite crystals is carried out as indicated previously by observation with a scanning electron microscope (SEM).
• a set of images is carried out at a magnification of at least 5000.
• the diameter of at least 200 crystals is then measured using a dedicated software, for example the Smile View software from the LoGraMi editor.
• the accuracy is of the order of 3%.
• the morphology of the crystals is qualified from SEM photos taken at magnification adapted to the size of the crystals (see Figure 1). Measurement of the mesoporous outer surface (m 2, g '1 ) by the so-called t-plot method:
• a line can be drawn which defines an adsorbed Y intercept which allows the microporous surface to be calculated; if the solid is not microporous the line goes through 0.
• the powder is dispersed in ethanol: 1 minute under ultrasound. One drop of the solution is deposited on a microscopy grid. The sample is allowed to dry at room temperature. The observation is made with a transmission electron microscope (FEI CM 200) at a voltage of 120 kV.
• FEI CM 200 transmission electron microscope
• magnifications obtained from x 300000 make it possible to visualize the presence of the mesopores and to estimate their diameters.
• An elemental chemical analysis of the zeolite with hierarchical porosity can be carried out according to various analytical techniques known to those skilled in the art. Among these techniques, mention may be made of the technique of chemical analysis by X-ray fluorescence as described in standard NF EN ISO 12677: 201 1 on a wavelength dispersive spectrometer (WDXRF), for example Tiger S8 of the Bruker company.
• WDXRF wavelength dispersive spectrometer
• X-ray fluorescence is a non-destructive spectral technique exploiting the photoluminescence of atoms in the X-ray domain, to establish the elemental composition of a sample.
• the excitation of the atoms generally by an X-ray beam or by bombardment with electrons, generates specific radiations after return to the ground state of the atom.
• the fluorescence spectrum X has the advantage of depending very little on the chemical combination of the element, which offers a precise determination, both quantitative and qualitative. A measurement uncertainty of less than 0.4% by weight is obtained conventionally after calibration for each oxide.
• each of the zeolite structures has a diffractogram (or diffraction spectrum) that is defined by the positioning of the diffraction peaks and by their relative intensities.
• the zeolite crystals are spread and smoothed on a sample holder by simple mechanical compression.
• the conditions of acquisition of the diffraction spectrum realized on the Bruker D5000 apparatus are as follows:
• the interpretation of the diffraction spectrum (or diffractogram) obtained is carried out with the EVA software with phase identification using the ICDD PDF-2 base, release 201 1 which makes it possible to highlight a phase perfectly. crystalline.
• the amount of zeolite fractions is measured by XRD analysis. This analysis is carried out on a Bruker brand apparatus, then the quantity of zeolite fractions is evaluated using Bruker's TOPAS software.
• a growth gel is prepared by adding 1446 g of colloidal silica (Ludox AM-30 containing 30 % by weight of SiO 2 ) at 25 ° C in an aluminate solution containing 184 g of sodium hydroxide (NaOH), 138 g of alumina trihydrate (Al 2 O 3 , 3H 2 O, containing 65.2% by weight of AI 2 0 3 ) and 800 g of water at 25 ° C in 25 minutes with a stirring speed of 300 rpm "1 .
• colloidal silica Lidox AM-30 containing 30 % by weight of SiO 2
• NaOH sodium hydroxide
• Al 2 O 3 , 3H 2 O containing 65.2% by weight of AI 2 0 3
• the stoichiometry of growth gel is: 2.5 Na 2 0 / AI 2 0 3 / Si0 8.0 2/1 17H 2 0.
• the homogenization of the gel growth is carried out with stirring at 300 tr.min -1 for 25 minutes at 25 ° C.
• nucleating gel (2% by weight) of composition 12 Na 2 0 / AI 2 0 3 / 10 Si0 2/180 H 2 0 prepared by mixing a sodium silicate and sodium aluminate under stirring for 1 hour at 40 ° C. After 5 minutes of homogenization at 300 tr.min "1, the stirring speed is reduced to 100 r "1 and continued for 30 minutes.
• the solids are recovered on sintered and then washed with deionized water until neutral pH.
• the drying is carried out in an oven at 90 ° C for 8 hours, the loss on ignition of the dried product is 23% by weight.
• the calcination of the dried product necessary to release both the microporosity (water) and the mesoporosity by eliminating the structuring agent is carried out with the following temperature profile: 30 minutes of temperature rise at 200 ° C., then 1 time to bearing at 200 ° C, then 3 hours of temperature rise at 550 ° C, and finally 1.5 hours of bearing at 550 ° C.
• a pure mesoporous Y zeolite (identification by X-ray diffraction spectrum) is thus obtained, with an Si / Al atomic ratio determined by X fluorescence equal to 2.6 and a microporous volume equal to 0.330 cm 3 . g "1 .
• Example 2 The procedure is as described in Example 1, with a TPOAC / Al 2 O 3 molar ratio of 0.02. A pure mesoporous Y zeolite (XRD) with an Si / Al atomic ratio determined by X fluorescence equal to 2.6 and a microporous volume equal to 0.332 cm 3 is thus obtained. g "1 .
• Example 2 The procedure is as described in Example 1, with a molar ratio TPOAC / Al 2 O 3 of 0.08.
• the growth gel is prepared in a 3-liter reactor by adding 1136 g of colloidal silica (Ludox AM-30 containing 30% by weight of SiO 2 ) at 25 ° C. in an aluminate solution containing 145 g. of sodium hydroxide (NaOH), 11 g of alumina trihydrate (Al 2 O 3 , 3H 2 O, containing 65.2% by weight of Al 2 O 3 ) and 626 g of water at 25 ° C. 3 minutes with a stirring speed of 2500 rpm "1 .
• colloidal silica Lidox AM-30 containing 30% by weight of SiO 2
• aluminate solution containing 145 g. of sodium hydroxide (NaOH)
• 11 g of alumina trihydrate Al 2 O 3 , 3H 2 O, containing 65.2% by weight of Al 2 O 3
• 626 g of water at 25 ° C. 3 minutes with a stirring speed of 2500 rpm "1 .
• the stoichiometry of growth gel is: 2.5 Na 2 0 / AI 2 0 3 / Si0 8.0 2/1 17H 2 0.
• the homogenization of the gel growth is carried out with stirring at 1200 tr.min -1 for 5 minutes at 25 ° C.
• the growth gel is transferred to a stirred 3-liter reactor with an Archimedean screw. b) Addition of the nucleation gel
• Maturing is carried out at 25 ° C. at 100 rpm for 10 hours.
• the stirring speed was maintained at 100 r "1 and is carried out a temperature rise to 95 ° C over 2 hours. After 36 hours bearing at 95 ° C, the reaction medium is cooled by circulating cold water in the jacket to stop the crystallization.
• the solids are recovered on sintered and then washed with deionized water until neutral pH.
• the drying is carried out in an oven at 90 ° C. for 8 hours.
• the loss on ignition of the dried product is 22% by weight.
• the calcination of the dried product necessary to release both the microporosity (water) and the mesoporosity by eliminating the structuring agent is carried out with the following temperature profile: 30 minutes of temperature rise at 200 ° C., then 1 bearing time at 200 ° C, then 3 hours of temperature rise at 550 ° C, and finally 1.5 hours of bearing at 550 ° C.
• the Si / Al ratio of YPH determined by X-ray fluorescence is 2.4.
• the porosity characteristics are summarized in Table 1.
• FIG. 1 SEM photo, magnification x 5000
• FIG. 2 TEM photo, magnification x 300000
• the size of the crystals is between 3 ⁇ and 7 ⁇ .
• the zeolite obtained has a crystal size of between 1 ⁇ and 3 ⁇ , that is to say less than the size of the crystals of the zeolite obtained in Example 4.
• the porosity characteristics are calculated from nitrogen adsorption / desorption isotherms at the temperature of the liquid nitrogen of a previously degassed powder at 300 ° C. C under vacuum. Measurements are made on an ASAP 2020 Micromeritics device.
• microporous volume (cm 3, g -1 ) is calculated according to the Dubinin-Raduskevitch theory
• the mesoporous outer surface (m 2, g -1 ) is calculated from the t-plot model.
• the mesopore size distribution is calculated by the Density Functional Theory (DFT) method with the cylindrical Pore model.
• DFT Density Functional Theory
• the X-ray diffraction makes it possible to identify the crystalline phases present in the powder from the reference spectra (or diffractograms) of the various zeolite structures and to demonstrate the level of crystallinity of the solids produced as a function of the peak intensity.
• FIG. 3 shows the diffractogram (a) of the non-mesoporous Y zeolite of reference (CBV 100) and the diffractogram (b) of the YPH zeolite of Example 4.
• This comparison shows the similarity of the intensities of the diffraction peaks between the reference zeolite and that of the invention (Example 4). This shows that the crystallinity (and therefore the microporous volume) is similar in these two zeolites.
• the results of the hierarchical porosity Y (YPH) Y zeolites of Examples 1, 2, 3 and 4 are summarized in Table 1 below:
• Zeolite Y CBV 100 Zeolyst International's non-mesoporous zeolite reference, ⁇ : microporous volume calculated with Dubinin-Raduskevitch equation.
• the synthesis method implemented with the use of a seeding gel and a nucleation gel makes it possible to vary the microporous volume / mesoporous surface distribution while obtaining a pure Y type FAU (Faujasite) zeolite. that is, without observing other crystalline forms.
• the method described in the present invention is economically viable, simple to implement on an industrial scale, with a very significant time saving compared to the syntheses described in the prior art.
• the synthesis method of the invention makes it possible to obtain quite satisfactory yields, generally greater than 90%, relative to the amount of aluminum involved and which is the element in defect in the gel of synthesis.

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