FR3052449A1 - PROCESS FOR THE PREPARATION OF A BETA ZEOLITHE - Google Patents

Abstract

A process for preparing a zeolite beta comprising at least the following steps: i) mixing, in an aqueous medium, at least one source of at least one oxide XO 2, at least one source of at least one oxide Y 2 O 3, at least one nitrogen-containing organic compound R, R being 1,6-bis (methylpiperidinium) hexane dihydroxy, said step i) being carried out in the absence of at least one source of at least one alkali metal and or alkaline earth of valence n, the mixture having the following molar composition: XO2 / Y2O3 between 5 and 70, H2O / XO2 between 1 and 100, R / XO2 between 0.01 to 0.5, in which X is one or more tetravalent element (s) chosen from the group consisting of the following elements: silicon, germanium, titanium, where Y is one or more trivalent element (s) chosen in the group formed by the following elements: aluminum, iron, boron, indium and gallium, ii) the hydrothermal treatment of said mixture at a temperature e between 120 ° C and 200 ° C for a period of between 1 day and 10 days, until said zeolite beta is formed.

Description

Technical area

The present invention relates to a new process for preparing a zeolite beta produced in the presence of a specific structural organic species comprising a quaternary ammonium function. Said zeolite beta obtained according to the process of the invention is advantageously used as a catalyst, adsorbent or separating agent.

Prior art

Crystallized microporous materials, such as zeolites or silicoaluminophosphates, are solids widely used in the petroleum industry as catalyst, catalyst support, adsorbent or separating agent. Although many microporous crystalline structures have been discovered, the refining and petrochemical industry is still searching for new zeolitic structures that have particular properties for applications such as gas purification or separation, conversion of carbon species or others.

Zeolite beta is a known solid which is described as consisting of a very disordered intergrowth of two polymorphs, polymorph A and polymorph B, which are usually found in a 60: 40 ratio (JM Newsam et al., Proc. R. Soc. London A, 420, 375 (1988).

Wadlinger, et al US Pat., 3308069 (1967) describes the synthesis of zeolite beta in the presence of tetraethylammonium cation (TEA +) as a structuring agent.

Camblor et al in Stud. Surf. Sci. Catal., 105, 341 (1997) and Bein et al. in Microporous Mesoporous Mater., 90, 237 (2006) obtain zeolite beta using the same structuring agent (TEAOH).

Camblor et al. in Microporous and Mesoporous Materials, 48, 11-22 (2001) provides numerous examples of organic species for the synthesis of beta zeolites such as tetraethylammonium, 6-azoniaspiro [5.5] undecane, N, N, N, N ', N', N'-hexaméthyldecane-1,10-diammonium. Arranz et al. in Stud. Surf. Sci. Catal., 154, 257-264 (2004) describe the use of the dibenzyldimethylammonium cation as a structuring organic species in the synthesis of zeolite beta.

Corma et al. in Chem. Sci., 7, 102 (2016) describes the synthesis of zeolite beta in the presence of the following ammonium salts: 1,10- (pentane-1,5-diyl) bis (1-butylpyrrolidin-1-indium) and 1 10- (pentane-1,5-diyl) bis (1-butylazepan-1-ium) as a structuring agent.

Brief description of the invention

The present invention relates to a method for preparing a zeolite beta comprising at least the following steps: i) mixing, in an aqueous medium, at least one source of at least one oxide XO 2, at least one source of at least one oxide Y203, at least one nitrogen-containing organic compound R, R being 1,6-bis (methylpiperidinium) hexane dihydroxy, said step i) being carried out in the absence of at least one source of at least one at least one alkali metal and / or alkaline earth metal of valency η, n being an integer greater than or equal to 1, the mixture having the following molar composition: XO 2 / Y 2 O 3 between 5 and 70, H 2 O / XO 2 between 1 and 100, preferably between 10 and 70, R / X02 between 0.01 to 0.5, preferably between 0.05 and 0.35, wherein X is one or more tetravalent element (s) chosen in the group formed by the following elements: silicon, germanium, titanium, preferably silicon, Y is one or more trivalen element (s) t (s) chosen from the group formed by the following elements: aluminum, iron, boron, indium and gallium, preferably aluminum, ii) the hydrothermal treatment of said mixture at a temperature between 120 ° C and 200 ° C for a period of time between 1 days and 10 days, until said zeolite beta is formed.

It has been found that the organic nitrogen compound 1,6-bis (methylpiperidinium) hexane in its dihydroxide form, mixed with at least one source of at least one tetravalent element, at least one source of at least one trivalent element in proportions such that the ratio XO2 / Y2O3 is between 15 and 70, and in the absence of at least one source of at least one alkaline and / or alkaline earth metal of valence n, leads to the production of a beta zeolite of high purity. Any other crystallized or amorphous phase is generally and very preferably absent from the crystallized solid consisting of zeolite beta obtained at the end of the preparation process.

An advantage of the present invention is therefore to provide a process for the preparation of a high purity beta zeolite.

Another advantage of the present invention is to allow the preparation, by the combination of the use of a particular structuring agent and very specific operating conditions, of a zeolite beta having a crystallite size measured by scanning electron microcopy. (MEB) between 10 and 100 nm, preferably between 10 and 80 nm and preferably between 0 and 70 nm.

Detailed description of the invention

The present invention relates to a method for preparing a zeolite beta comprising at least the following steps: i) mixing, in an aqueous medium, at least one source of at least one oxide XO 2, at least one source of at least one oxide Y203, at least one nitrogen-containing organic compound R, R being 1,6-bis (methylpiperidinium) hexane dihydroxide, said step i) being carried out in the absence of at least one source of at least one alkali metal and / or alkaline earth metal of valency η, n being an integer greater than or equal to 1, the mixture having the following molar composition: X02 / Y203 between 5 and 70, H20 / X02 between 1 and 100 , preferably between 10 and 70, R / XO2 between 0.01 to 0.5, preferably between 0.05 and 0.35, wherein X is one or more tetravalent element (s) chosen (s) ) in the group formed by the following elements: silicon, germanium, titanium, preferably silicon, Y is one or more element (s) sorting are chosen from the group formed by the following elements: aluminum, iron, boron, indium and gallium, preferably aluminum, ii) the hydrothermal treatment of said mixture at a temperature of between 120 ° C. and 200 ° C. ° C for a period of time between 1 days and 10 days, until said zeolite beta is formed.

According to the invention, at least one source of at least one oxide XO2 is incorporated in the mixture for the implementation of step (i) of the preparation process, X being one or more tetravalent element (s) (s) chosen from the group formed by the following elements: silicon, germanium, titanium. Very preferably, X is silicon. The source (s) of said tetravalent element (s) may be any compound comprising element X and capable of releasing this element in aqueous solution in reactive form. When X is titanium, Ti (EtO) 4 is advantageously used as a source of titanium. In the preferred case where X is silicon, the silicon source may be any of the sources commonly used for the synthesis of zeolites, for example powdered silica, silicic acid, colloidal silica, dissolved silica or tetraethoxysilane (TEOS). Among the powdered silicas, it is possible to use precipitated silicas, especially those obtained by precipitation from an alkali metal silicate solution, pyrogenic silicas, for example "CAB-O-SIL" and silica gels. Colloidal silicas having different particle sizes, for example having a mean equivalent diameter of between 10 and 15 nm or between 40 and 50 nm, such as those sold under registered trademarks such as "LUDOX", may be used. Preferably, the silicon source is LUDOX HS-40.

According to the invention, at least one source of at least one oxide Y203 is incorporated in the mixture for the implementation of said step (i) of the preparation process according to the invention, Y being one or more element (s) ) trivalent (s) chosen from the group formed by the following elements: aluminum, iron, boron, indium and gallium. Very preferably, Y is aluminum. In the preferred case where Y is aluminum, the aluminum source is preferably an aluminum salt and preferably aluminum hydroxide, or an aluminum salt, for example chloride, nitrate, or sulphate, an aluminum alkoxide for example alumium isopropoxide, or alumina proper, preferably in hydrated or hydratable form, such as for example colloidal alumina, pseudoboehmite, gamma alumina or alpha or beta trihydrate. It is also possible to use mixtures of the sources mentioned above.

According to the invention, at least one nitrogen-containing organic compound R, R being 1,6-bis (methylpiperidinium) hexane dihydroxide, the structural formula of which is given below, is incorporated in the mixture for the implementation of said step (i) of the preparation process according to the invention.

Said organic species R, which acts as a structurant, can be removed by the conventional routes known from the state of the art such as heat and / or chemical treatments.

According to the invention, said step i) is carried out in the absence of at least one source of at least one alkali metal and / or alkaline earth metal of valence n preferably chosen from lithium, potassium, sodium, magnesium and calcium and the mixture of at least two of these metals. Preferably, said step i) is carried out in the absence of a source of sodium and preferably in the absence of sodium hydroxide.

According to the invention, the reaction mixture obtained in step (i) has the following molar composition: XO 2 / Y 2 O 3 between 5 and 70, preferably between 15 and 70 and preferably between 15 and 60, H 2 O / XO 2 between 1 and 100, preferably between 10 and 70, R / XO2 between 0.01 to 0.5, preferably between 0.05 and 0.35, and where X, Y and R have the same definition as above. . Step (i) of the process according to the invention consists in preparing an aqueous reaction mixture called gel and containing at least one source of at least one oxide XO 2, at least one source of at least one oxide Y 2 O 3, at least one nitrogen-containing organic compound R, R being 1,6-bis (methylpiperidinium) hexane dihydroxide in the absence of at least one source of one or more alkali metal (s) and / or alkaline earth metal (s). The amounts of said reagents are adjusted so as to confer on this gel a composition enabling it to crystallize into a zeolite beta.

It may be advantageous to add seeds to the reaction mixture during said step i) of the process of the invention in order to reduce the time required for formation of the zeolite beta crystals and / or the total crystallization time. Said seeds also promote the formation of said zeolite beta at the expense of impurities. Such seeds include crystalline solids, including zeolite beta crystals. The crystalline seeds are generally added in a proportion of between 0.01 and 10% of the mass of the source of at least one oxide XO 2, used in the reaction mixture.

According to step (ii) of the process according to the invention, the gel is subjected to a hydrothermal treatment, preferably carried out at a temperature of between 120 ° C. and 200 ° C. for a period of time ranging from 1 day to 10 days, up to zeolite beta is formed. The gel is advantageously placed under hydrothermal conditions under an autogenous reaction pressure, optionally by adding gas, for example nitrogen, at a temperature preferably of between 120 ° C. and 195 ° C., preferably between 150 ° C. and 95 ° C. ° C, until the formation of zeolite beta crystals. The time required to obtain the crystallization varies according to the invention between 1 day and 10 days, preferably between 2 days and 9 days and more preferably between 3 days and 8 days. The reaction is generally carried out with stirring or without stirring, preferably in the presence of stirring. At the end of the reaction, when said zeolite beta is formed following the implementation of said step ii) of the preparation process according to the invention, the solid phase formed of zeolite beta is filtered, washed and dried. The drying is generally carried out at a temperature between 20 and 150 ° C, preferably between 60 and 100 ° C for a period of between 5 and 24 hours. The zeolite beta, calcined, is generally analyzed by X-ray diffraction, this technique also making it possible to determine the purity of said zeolite obtained by the process of the invention. Very advantageously, the process of the invention leads to the formation of a zeolite beta, in the absence of any other crystalline or amorphous phase. Said zeolite, after the drying step, is then ready for subsequent steps such as calcination and ion exchange. For these steps, all the conventional methods known to those skilled in the art can be used.

Calcination of the zeolite beta obtained according to the process of the invention is preferably carried out at a temperature between 500 and 700 ° C for a period of between 5 and 20 hours. The zeolite beta obtained at the end of the calcination step is devoid of any organic species and in particular of the organic template R. At the end of said calcination step, the X-ray diffraction makes it possible to verify that the solid obtained The solid obtained has the X-ray diffraction pattern including at least the lines listed in Table 1.

This diffraction pattern is obtained by radiocrystallographic analysis using a diffractometer using the conventional powder method with copper Και radiation (λ = 1.5406). From the position of the diffraction peaks represented by the angle 2Θ, we calculate, by the Bragg relation, the characteristic dhki reticular equidistances of the sample. The measurement error A (dhki) on dhki is calculated by means of the Bragg relation as a function of the absolute error Δ (2Θ) assigned to the measurement of 2Θ. An absolute error Δ (2Θ) equal to ± 0.02 ° is commonly accepted. The relative intensity lrei assigned to each dhki value is measured from the height of the corresponding diffraction peak. The X-ray diffraction pattern of the crystallized beta solid according to the invention comprises at least the dhki lines given in Table 1. In the dhki column, the mean values of the inter-reticular distances in Angstroms are given ( AT). Each of these values shall be assigned the measurement error A (dhki) between ± 0,6 and ± 0,01 Å.

Table 1: Average values of dhki and relative intensities measured on an X-ray diffraction diagram of calcined calcined solid BEA

where FF = very strong; F = strong; m = average; mf = weak medium; f = weak; ff = very weak. The relative intensity lrei is given in relation to a scale of relative intensity where it is assigned a value of 100 to the most intense line of the X-ray diffraction pattern: ff <15; <F <30; <Mf <50; 50 <m <65; 65 <F <85; FF> 85.

The process according to the invention makes it possible, by virtue of the combination of the use of a particular structuring agent and of very specific operating conditions, of a beta zeolite having a crystallite size measured by scanning electron microcopy (SEM) between 10 and 100 nm, preferably between 10 and 80 nm and preferably between 0 and 70 nm.

It is also advantageous to obtain the hydrogen form of the zeolite beta obtained by the process according to the invention. Said hydrogen form can be obtained by carrying out an ion exchange with an acid, in particular a strong mineral acid such as hydrochloric, sulfuric or nitric acid, or with a compound such as ammonium chloride, sulphate or nitrate . The ion exchange can be carried out by suspending said zeolite beta one or more times with the ion exchange solution. Said zeolite can be calcined before or after the ion exchange, or between two ion exchange steps. The zeolite is preferably calcined prior to the ion exchange, to remove any organic substance included in the zeolite porosity, as ion exchange is facilitated.

The zeolite beta obtained by the process of the invention may be used after ion exchange as an acidic solid for catalysis in the fields of refining and petrochemistry. It can also be used as an adsorbent for pollution control or as a molecular sieve for separation.

For example, when it is used as a catalyst, the zeolite prepared according to the process of the invention is calcined, exchanged and is preferably in hydrogen form, and may be combined with an inorganic matrix, which may be inert or catalytically active. , and a metallic phase. The inorganic matrix can be present simply as a binder to hold small particles of the zeolite together in the various known forms of catalysts (extrudates, pellets, beads, powders), or can be added as a diluent to impose the degree of conversion in a a process which would progress if not at a rate too fast leading to a clogging of the catalyst as a result of a significant formation of coke. Typical inorganic matrices are in particular support materials for catalysts such as silica, the various forms of alumina, magnesia, zirconia, oxides of titanium, boron, titanium, zirconium, aluminum phosphates, kaolinic clays, bentonites, montmorillonites, sepiolite, attapulgite, fulling earth, synthetic porous materials such as SiO2-Al2O3, SiO2-ZrO2, SiO2-ThO2, SiCVBeO, SiO2-TiO2 or any combination thereof . The inorganic matrix may be a mixture of different compounds, in particular an inert phase and an active phase.

The zeolite prepared according to the method of the invention may also be associated with at least one other zeolite and act as the main active phase or additive.

The metal phase is introduced on the zeolite alone, the inorganic matrix alone or the inorganic-zeolite matrix assembly by ion exchange or impregnation with cations or oxides chosen from the following elements: Cu, Ag, Ga, Mg, Ca, Sr, Zn, Cd, B, Al, Sn, Pb, V, P, Sb, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Pt, Pd, Ru, Rh, Os, Ir and any other element of the periodic table of elements. The metals can be introduced either all in the same way, or by different techniques, at any time of the preparation, before or after shaping and in any order. In addition, intermediate treatments such as for example calcination and / or reduction can be applied between the deposits of different metals.

The catalyst compositions comprising the zeolite beta prepared according to the process of the invention are generally suitable for carrying out the main hydrocarbon conversion processes and the synthesis reactions of organic compounds such as ethers.

Any shaping method known to those skilled in the art is suitable for the catalyst comprising zeolite beta. It is possible to use, for example, pelletizing or extruding or forming beads. The shaping of the catalyst containing the zeolite prepared by the process of the invention and at least partly in acid form is generally such that the catalyst is preferably in the form of extrudates or beads for use. The invention is illustrated by the following examples, which in no way present a limiting character.

Example 1: Preparation of 1,6-bis (methylpiperidinium) hexane dihydrogen (structuring R (OH) p) 18.9 g of Ag20 (0.08 mol, 99%, Aldrich) are added to a Teflon beaker of 250 ml containing 30 g of the template dibromide 1,6-bis (methylpiperidinium) hexane (0.07 mole) and 100 ml of deionized water. The reaction medium is stirred in the dark for 12 hours. The mixture is then filtered. The filtrate obtained is composed of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide. The assay of this species is carried out by proton NMR using formic acid as a standard.

EXAMPLE 2 Preparation of a Beta Solid According to the Invention 902 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 1063 mg of deionized water and stirred for 10 minutes. Subsequently, 10 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.015 Al 2 O 3: 0.17 R (OH) 2: 33.33 H 2 O, a SiO 2 / Al 2 C ratio> 3 of 66. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 8 days at 170 ° C agitation. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta. The diffraction pattern made on the calcined Beta solid is given in FIG.

The crystallite size of the zeolite beta according to Example 2 measured by scanning electron microcopy (SEM) is between 22 and 75 nm.

Example 3 Preparation of a Beta Solid According to the Invention 2319 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 3000 mg of deionized water and stirred for 10 minutes. Subsequently, 35 mg of aluminum hydroxide (58.55% by weight, Merck) and 901 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.0333 Al 2 O 3: 0.25 R (OH) 2: 50 H 2 O, ie a SiO 2 / Al 2 O ratio> 3 of 30. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 8 days at 170 ° C agitation. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 3 measured by scanning electron microcopy (SEM) is between 10 and 35 nm.

EXAMPLE 4 Preparation of a Beta Solid According to the Invention 1786 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 361 mg of deionized water and stirred for 10 minutes. Subsequently, 9 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.0143 Al 2 O 3: 0.33 R (OH) 2: 33.3 H 2 O, ie a SiO 2 / Al 2 O 3 ratio of 70. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 3 days at 190 ° C agitation. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 4 measured by scanning electron microcopy (SEM) is between 10 and 40 nm.

EXAMPLE 5 Preparation of a Beta Solid According to the Invention 902 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 1055 mg of deionized water and stirred for 10 minutes. Subsequently, 30 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.05 Al 2 O 3: 0.1666 R (OH) 2: 33.3 H 2 O, ie an SiO 2 / Al 2 O ratio> 3 of 20. The mixture is stirred vigorously for half an hour . The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 3 days at 190 ° C agitation. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 5 measured by scanning electron microcopy (SEM) is between 20 and 65 nm.

Example 6 Preparation of a Beta Solid According to the Invention 1786 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 351 mg of deionized water and stirred for 10 minutes. Subsequently, 30 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.05 Al 2 O 3: 0.33 R (OH) 2: 33.3 H 2 O is a SiO 2 / Al 2 O 3 ratio of 20. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 3 days at 190 ° C. with stirring. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 6 measured by scanning electron microcopy (SEM) is between 10 and 35 nm.

EXAMPLE 7 Preparation of a Beta Solid According to the Invention 1353 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 696 mg of deionized water and stirred for 10 minutes. Subsequently, 30 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.05 Al 2 O 3: 0.25 R (OH) 2: 33.3 H 2 O is a ratio SiO 2 / Al 2 O 3 of 20. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 3 days at 190 ° C agitation. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 7 measured by scanning electron microcopy (SEM) is between 15 and 35 nm.

EXAMPLE 8 Preparation of a Beta Solid According to the Invention 902 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 1055 mg of deionized water and stirred for 10 minutes. Subsequently, 30 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.05 Al 2 O 3: 0.166 R (OH) 2: 33.3 H 2 O is a SiO 2 / Al 2 O 3 ratio of 20. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 8 days at 170 ° C. with stirring. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 8 measured by scanning electron microcopy (SEM) is between 10 and 25 nm.

Example 9 Preparation of a Beta Solid According to the Invention 1786 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 351 mg of deionized water and stirred for 10 minutes. Subsequently, 30 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.05 Al 2 O 3: 0.33 R (OH) 2: 33.3 H 2 O is a ratio SiO 2 / Al 2 O 3 of 30. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 8 days at 170 ° C. with stirring. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a bearing at 200 ° C maintained for 2 hours, a rise in temperature up to 550 ° C followed by a plateau at 550 ° Cmaintenu for 8 hours and a return to temperature room.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 9 measured by scanning electron microcopy (SEM) is between 10 and 25 nm.

EXAMPLE 10 Preparation of a Beta Solid According to the Invention 1353 mg of an aqueous solution of 1,6-bis (methylpiperidinium) hexane dihydroxide (20.47% by weight) prepared according to Example 1 were mixed with 696 mg of deionized water and stirred for 10 minutes. Subsequently, 30 mg of aluminum hydroxide (58.55% by weight, Merck) and 526 mg of colloidal silica (Ludox HS40, 40% by weight, Aldrich) were incorporated into the synthesis mixture, and keeping stirring the time necessary to evaporate the solvent until the desired gel concentration. The molar composition of the mixture is as follows: SiO 2: 0.05 Al 2 O 3: 0.25 R (OH) 2: 33.3 H 2 O, ie a SiO 2 / Al 2 O 3 ratio of 20. The mixture is stirred vigorously for half an hour. The mixture is then transferred, after homogenization, into an autoclave. The autoclave is heated for 8 days at 170 ° C agitation. The crystallized product obtained is filtered, washed with deionized water (to reach a neutral pH) and then dried overnight at 100 ° C. The solid is then introduced into a muffle furnace where the calcination is carried out: the calcination cycle comprises a rise in temperature up to 200 ° C, a plateau at 200 ° C maintained for 2 hours, a temperature rise up to 550 ° C followed by a plateau at 550 ° C maintained for 8 hours and then returned to room temperature.

The calcined solid product was analyzed by X-ray diffraction and identified as solid Beta.

The crystallite size of the zeolite beta according to Example 10 measured by scanning electron microcopy (SEM) is between 10 and 25 nm.

Claims (11)

A process for preparing a zeolite beta comprising at least the following steps: i) mixing, in an aqueous medium, at least one source of at least one oxide XO 2, at least one source of at least one oxide Y 2 O 3, at least one nitrogen-containing organic compound R, R being 1,6-bis (methylpiperidinium) hexane dihydroxide, said step i) being carried out in the absence of at least one source of at least one alkali metal and / or alkaline earth metal of valency η, n being an integer greater than or equal to 1, the mixture having the following molar composition: XO 2 / Y 2 O 3 of between 5 and 70, H 2 O / XO 2 of between 1 and 100, including R / XO 2 between 0.01 to 0.5, wherein X is one or more tetravalent element (s) selected from the group consisting of silicon, germanium, titanium, Y is one or more elements ( s) trivalent (s) chosen from the group formed by the following elements: aluminum, iron, boron, indium and gallium, ii) the treatment hy drothermal said mixture at a temperature between 120 ° C and 200 ° C for a period between 1 φυΓ and 10 days, until said zeolite beta is formed. 2. Preparation process according to claim 1 wherein X is silicon. 3. Preparation process according to claim 1 or claim 2 wherein Y is aluminum. 4. Preparation process according to one of claims 1 to 3 wherein said step i) is carried out in the absence of sodium hydroxide. 5. Preparation process according to one of claims 1 to 4 wherein the reaction mixture obtained in step (i) has the following molar composition: XO2 / Y2O3 between 15 and 60, H2O / XO2 between 10 and 70 , R / XO2 between 0.05 and 0.35, and where X, Y and R have the same definition as above. 6. Preparation process according to claim 5 wherein the hydrothermal treatment of step ii) is carried out at a temperature between 120 ° C and 195 ° C. 7. Preparation process according to claim 6 wherein the hydrothermal treatment of step ii) is carried out at a temperature between 150 ° C and 195 ° C. 8. Preparation process according to one of claims 1 to 7 wherein the hydrothermal treatment of step ii) is carried out for a period of between 2 days and 9 days. 9. Preparation process according to claim 8 wherein the hydrothermal treatment of step ii) is carried out for a period of between 3 days and 8 days. 10. A method of preparation according to one of claims 1 to 9 wherein said method comprises, following said step ii), a step of filtering, washing and then drying the zeolite beta formed, drying being carried out. a temperature between 20 and 150 ° C for a period of between 5 and 24 hours. 11. A method of preparation according to one of claims 1 to 10 wherein said process also comprises a step of calcination of zeolite beta obtained, said calcination step being carried out at a temperature between 500 and 700 ° C for a period of time between 5 and 20 hours.