PROCESS FOR PREPARING AN IZM-2 ZEOLITE IN THE PRESENCE OF A NITROGENOUS ORGANIC STRUCTURING AGENT IN HYDROXIDE FORM AND OF AN ALKALI METAL CHLORIDE, IN FLUORINATED OR NON-FLUORINATED MEDIUM

Abstract

The invention relates to a process for preparing an IZM-2 zeolite, comprising at least: i) mixing, in aqueous medium, of at least one source of at least one tetravalent element X (XO.sub.2), at least one source of at least one trivalent element (Y.sub.2O.sub.3), 1,6-bis(methylpiperidinium)hexane dihydroxide, at least one source of at least one alkali metal M of valency n chosen from alkali metal chlorides, n being an integer greater than or equal to 1, M being chosen from lithium, potassium, sodium and caesium, and the mixture of at least two of these metals, and optionally in the presence of a source of at least one fluoride anion, BF, the mixture having a specific molar composition to obtain a homogeneous precursor gel; ii) hydrothermal treatment of said precursor gel.

Claims

1. Process for preparing an IZM-2 zeolite, comprising at least the following steps: i) mixing, in aqueous medium, of at least one source of at least one tetravalent element X in oxide form XO.sub.2, at least one source of at least one trivalent element in oxide form Y.sub.2O.sub.3, a nitrogenous organic compound R(OH).sub.2, which is 1,6-bis(methylpiperidinium)hexane dihydroxide, at least one source of at least one alkali metal M of valency n chosen from alkali metal chlorides, n being an integer greater than or equal to 1, M being chosen from lithium, potassium, sodium and caesium, and the mixture of at least two of these metals, and optionally in the presence of at least one fluoride anion, BF, the reaction mixture having the following molar composition: XO.sub.2/Y.sub.2O.sub.3 between 70 and 350, H.sub.2O/XO.sub.2 between 1 and 100, R(OH).sub.2/XO.sub.2 between 0.006 and 0.25, M.sub.1/nCl/XO.sub.2 between 0.005 and 0.5, BF/XO.sub.2 between 0 and 0.25, with X being one or more tetravalent elements chosen from the group formed by the following elements: silicon, germanium, titanium, at least one element X being silicon, Y is one or more trivalent elements chosen from the group formed by the following elements: aluminium, iron, boron, indium and gallium, and at least one element Y being aluminium, until a homogeneous precursor gel is obtained, and BF being chosen from hydrofluoric acid in aqueous solution and fluorine salts in which B is a cation chosen from the cations NH.sub.4.sup.+, Na.sup.+, K.sup.+ and Li.sup.+; ii) hydrothermal treatment of said precursor gel obtained on conclusion of step i) at a temperature of between 120° C. and 220° C., for a time of between 1 day and 10 days.

2. Process according to claim 1, in which the mixture of step i) also comprises one or more tetravalent elements X other than silicon, chosen from the group formed by the following elements: germanium, titanium and/or one or more trivalent elements Y, other than aluminium, chosen from the group formed by the following elements: iron, boron, indium and gallium.

3. Process according to claim 1, in which the reaction mixture from step i) has the following molar composition: XO.sub.2/Y.sub.2O.sub.3 between 80 and 300 H.sub.2O/XO.sub.2 between 5 and 50 R(OH).sub.2/XO.sub.2 between 0.01 and 0.20 M.sub.1/nCl/XO.sub.2 between 0.01 and 0.4 BF/XO.sub.2 between 0 and 0.2, BF, X, Y, R and M having the abovementioned meaning.

4. Process according to claim 1, in which M is sodium.

5. Process according to claim 1, in which BF is a fluorine salt in which B is the NH.sub.4.sup.+ cation.

6. Process according to claim 1, in which the seed crystals of an IZM-2 zeolite are added to the reaction mixture from step i) in an amount of between 0.01% and 10% of the total mass of the sources of said tetravalent and trivalent element(s) in anhydrous form used in the reaction mixture, said seed crystals not being taken into account in the total mass of the sources of the tetravalent and trivalent elements.

7. Process according to claim 1, in which step i) comprises a step of maturing the reaction mixture obtained at a temperature of between 20 and 100° C., with or without stirring, for a time of between 30 minutes and 48 hours.

8. Process according to claim 1, in which the hydrothermal treatment of step ii) is performed under autogenous pressure at a temperature of between 150° C. and 195° C., for a time of between 2 days and 8 days.

9. Process according to claim 8, in which the solid phase obtained on conclusion of step ii) may be filtered, washed and dried at a temperature of between 20 and 150° C., preferably between 60 and 100° C., for a time of between 5 and 24 hours to obtain a dried zeolite.

10. Process according to claim 9, in which the dried zeolite is then calcined at a temperature of between 450 and 700° C. for a time of between 2 and 20 hours, the calcining possibly being preceded by a gradual temperature increase.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG. 1 represents the chemical formula of 1,6-bis(methylpiperidinium)hexane dihydroxide chosen as structuring agent in the synthetic process according to the invention.

[0055] FIG. 2 represents the X-ray diffraction pattern of the IZM-2 zeolite obtained according to Example 2.

[0056] Other characteristics and advantages of the synthetic process according to the invention will become apparent on reading the following description of non-limiting exemplary embodiments with reference to the appended figures described below.

[0057] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

[0058] In the foregoing and in the examples, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.

[0059] The entire disclosures of all applications, patents and publications, cited herein and of corresponding French application No. 19/10.619, filed Sep. 26, 2019, are incorporated by reference herein.

EXAMPLES

Example 1: Preparation of 1,6-bis(methylpiperidinium)hexane dihydroxide [R(OH).SUB.2.]

[0060] 50 g of 1,6-dibromohexane (0.20 mol, 99%, Alfa Aesar) are placed in a 1 L round-bottomed flask containing 50 g of N-methylpiperidine (0.51 mol, 99%, Alfa Aesar) and 200 mL of ethanol. The reaction medium is stirred at reflux for 5 hours. The mixture is then cooled to room temperature and then filtered. The mixture is poured into 300 mL of cold diethyl ether and the precipitate formed is then filtered off and washed with 100 mL of diethyl ether. The solid obtained is recrystallized from an ethanol/ether mixture. The solid obtained is dried under vacuum for 12 hours. 71 g of a white solid are obtained (i.e. a yield of 80%).

[0061] The product has the expected 1H NMR spectrum. 1H NMR (D2O, ppm/TMS): 1.27 (4H, m); 1.48 (4H, m); 1.61 (4H, m); 1.70 (8H, m); 2.85 (6H, s); 3.16 (12H, m).

[0062] 18.9 g of Ag2O (0.08 mol, 99%, Aldrich) are placed in a 250 ml Teflon beaker containing 30 g of the structuring agent 1,6-bis(methylpiperidinium) dibromide (0.07 mol) prepared according to Example 1 and 100 ml of deionized water. The reaction medium is stirred for 12 hours in the absence of light. The mixture is then filtered. The filtrate obtained is composed of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide. Assay of this species is performed by proton NMR using formic acid as standard.

Example 2: Preparation of an IZM-2 Solid According to the Invention

[0063] 3.486 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 were mixed with 1.434 g of deionized water. 0.427 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) is added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.009 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. 1.828 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the mixture, which is kept stirring for 15 minutes. Finally, 0.866 g of aqueous ammonium fluoride solution (10% by weight) is incorporated into the synthetic mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the composition of the desired precursor gel is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.25 Al.sub.2O.sub.3: 10 R(OH).sub.2: 9.6 NaCl: 1770 H.sub.2O: 10 NH.sub.4F, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio for the gel obtained of 240. The precursor gel is then transferred, after homogenization, into an autoclave. The autoclave is closed and then heated for 8 days at 170° C. with stirring at 32 rpm with a rotary spit system. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0064] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%. The diffraction pattern produced for the calcined IZM-2 microporous solid is given in FIG. 2.

Example 3: Preparation of an IZM-2 Solid According to the Invention

[0065] 43.564 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 were mixed with 26.721 g of deionized water. 5.328 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) is added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.111 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. 22.773 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the mixture, which is kept stirring for 15 minutes. Finally, 10.854 g of aqueous ammonium fluoride solution (10% by weight) are incorporated into the synthetic mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the composition of the desired precursor gel is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.25 Al.sub.2O.sub.3: 10 R(OH).sub.2: 9.6 NaCl: 1770 H.sub.2O: 10 NH.sub.4F, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio for the gel of 240. The precursor gel is then transferred into a 1000 mL stainless-steel reactor equipped with a stirring system with four inclined paddles. The reactor is closed and then heated for 8 days at 170° C. with stirring at 350 rpm. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0066] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%. The IZM-2 zeolite obtained has an SiO.sub.2/Al.sub.2O.sub.3 mole ratio of 222.3 as determined by X-ray fluorescence and ICP.

Example 4: Preparation of an IZM-2 Solid According to the Invention

[0067] 3.522 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 were mixed with 1.619 g of deionized water. 0.194 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) is added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.01 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. 1.837 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the mixture, which is kept stirring for 15 minutes. Finally, 0.863 g of aqueous ammonium fluoride solution (10% by weight) are incorporated into the synthetic mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the composition of the desired precursor gel is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.25 Al.sub.2O.sub.3: 10 R(OH).sub.2: 4.8 NaCl: 1770 H.sub.2O: 10 NH.sub.4F, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio of 240. The precursor gel is then transferred, after homogenization, into an autoclave. The autoclave is closed and then heated for 8 days at 170° C. with stirring at 32 rpm with a rotary spit system. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0068] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%.

Example 5: Preparation of an IZM-2 Solid According to the Invention

[0069] 39.497 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 were mixed with 26.011 g of deionized water. 2.273 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) are added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.102 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. 20.618 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the mixture, which is kept stirring for 15 minutes. Finally, 9.727 g of aqueous ammonium fluoride solution (10% by weight) are incorporated into the synthetic mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the composition of the desired precursor gel is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.25 Al.sub.2O.sub.3: 10 R(OH).sub.2: 4.8 NaCl: 1770 H.sub.2O: 10 NH.sub.4F, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio of 240. The precursor gel is then transferred into a 160 mL stainless-steel reactor equipped with a stirring system with four inclined paddles. The reactor is closed and then heated for 8 days at 170° C. with stirring at 350 rpm. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0070] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%. The product has an SiO.sub.2/Al.sub.2O.sub.3 mole ratio of 212.8 as determined by X-ray fluorescence and ICP.

Example 6: Preparation of an IZM-2 Solid According to the Invention

[0071] 3.473 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 are mixed with 1.819 g of deionized water. 0.921 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) are added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.009 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. Finally, 1.808 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the synthesis mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the desired precursor gel composition is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.25 Al.sub.2O.sub.3: 10 R(OH).sub.2: 20 NaCl: 1770 H.sub.2O, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio of 240. The precursor gel is then transferred, after homogenization, into an autoclave. The autoclave is closed and then heated for 6 days at 170° C. with stirring at 32 rpm with a rotary spit system. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0072] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%.

Example 7: Preparation of an IZM-2 Solid According to the Invention

[0073] 3.496 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 are mixed with 2.020 g of deionized water. 0.681 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) is added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.009 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. Finally, 1.835 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the synthesis mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the desired precursor gel composition is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.25 Al.sub.2O.sub.3: 10 R(OH).sub.2: 15 NaCl: 1770 H.sub.2O, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio of 240. The precursor gel is then transferred, after homogenization, into an autoclave. The autoclave is closed and then heated for 6 days at 170° C. with stirring at 32 rpm with a rotary spit system. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0074] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%.

Example 8: Preparation of an IZM-2 Solid According to the Invention

[0075] 1.831 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 are mixed with 3.578 g of deionized water. 0.722 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) is added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.011 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. Finally, 1.908 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the synthesis mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the desired precursor gel composition is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.3 Al.sub.2O.sub.3: 5 R(OH).sub.2: 15 NaCl: 1770 H.sub.2O, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio of 200. The precursor gel is then transferred, after homogenization, into an autoclave. The autoclave is closed and then heated for 4 days at 170° C. with stirring at 32 rpm with a rotary spit system. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0076] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%.

Example 9: Preparation of an IZM-2 Solid According to the Invention

[0077] 34.901 g of an aqueous solution of 1,6-bis(methylpiperidinium)hexane dihydroxide (18.36% by weight) prepared according to Example 1 are mixed with 20.085 g of deionized water. 6.799 g of sodium chloride (solid, purity of 99% by weight, Alfa Aesar) are added to the preceding mixture, and the preparation obtained is kept stirring for 10 minutes. 0.125 g of amorphous aluminium hydroxide gel (amorphous Al(OH).sub.3 gel, 58.55% Al.sub.2O.sub.3, Merck) is then incorporated and the synthetic gel is kept stirring for 15 minutes. Finally, 18.234 g of colloidal silica (Ludox HS40, 40% by weight, Aldrich) are incorporated into the synthesis mixture, which is kept stirring for 30 minutes to evaporate off the solvent until the desired precursor gel composition is obtained, i.e. a molar composition of the following mixture: 60 SiO.sub.2: 0.35 Al.sub.2O.sub.3: 10 R(OH).sub.2: 15 NaCl: 1770 H.sub.2O, i.e. an SiO.sub.2/Al.sub.2O.sub.3 ratio of 171. The precursor gel is then transferred into a 160 mL stainless-steel reactor equipped with a stirring system with four inclined paddles. The reactor is closed and then heated for 4 days at 170° C. with stirring at 350 rpm. The crystalline product obtained is filtered off, washed with deionized water and then dried overnight at 100° C. The solid is then introduced into a muffle furnace where a calcination step is performed: the calcination cycle comprises an increase in temperature of 1.5° C./minute up to 200° C., a steady stage at 200° C. maintained for 2 hours, an increase in temperature of 1° C./minute up to 550° C., followed by a steady stage at 550° C. maintained for 8 hours, then return to room temperature.

[0078] The calcined solid product was analysed by X-ray diffraction and identified as consisting of an IZM-2 zeolite with a purity of greater than 99.8%.

[0079] The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

[0080] From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.