Synthesis of a boron-containing zeolite with an MWW framework structure

Abstract

The present invention relates to a process for the production of a boron-containing zeolitic material having an MWW framework structure comprising YO.sub.2 and B.sub.2O.sub.3, wherein Y stands for a tetravalent element, wherein said process comprises (a) providing a mixture comprising one or more sources for YO.sub.2, one or more sources for B.sub.2O.sub.3, one or more organotemplates, and seed crystals, (b) crystallizing the mixture obtained in (a) for obtaining a layered precursor of the boron-containing MWW-type zeolitic material, (c) calcining the layered precursor obtained in (b) for obtaining the boron-containing zeolitic material having an MWW framework structure, wherein the one or more organotemplates have the formula (I)
R.sup.1R.sup.2R.sup.3N(I)
wherein R.sup.1 is (C.sub.5-C.sub.8)cycloalkyl, and
wherein R.sup.2 and R.sup.3 are independently from each other H or alkyl, as well as to a synthetic boron-containing zeolite which is obtainable and/or obtained according to the inventive process as well as to its use.

Claims

1. A synthetic boron-containing zeolitic material having an MWW framework structure, comprising YO.sub.2 and B.sub.2O.sub.3, where Y is a tetravalent element, wherein the boron-containing zeolitic material is obtained from a process comprising (a) crystallizing a mixture comprising one or more sources for YO.sub.2, one or more sources for B.sub.2O.sub.3, one or more organotemplates represented by formula (I), and one or more seed crystals, thereby obtaining a layered precursor of the boron-containing MWW-type zeolitic material:
R.sup.1R.sup.2R.sup.3N(I) where R.sup.1 is a (C.sub.5-C.sub.8)cycloalkyl group, and R.sup.2 and R.sup.3 are independently H or an alkyl group, and (b) calcining the layered precursor, thereby obtaining the boron-containing zeolitic material having an MWW framework structure.

2. The synthetic boron-containing zeolitic material of claim 1, wherein the one or more seed crystals comprise YO.sub.2 and X.sub.2O.sub.3, where X is a trivalent element selected from the group consisting of Al, B, In, Ga, and any combination thereof.

3. The synthetic boron-containing zeolitic material of claim 1, wherein the tetravalent element Y is selected from the group consisting of Si, Sn, Ti, Zr, Ge, and any combination thereof.

4. The synthetic boron-containing zeolitic material of claim 1, wherein the tetravalent element Y is Si, and the one or more sources for YO.sub.2 are selected from the group consisting of a silica, a silicate, a silicic acid, and any combination thereof.

5. The synthetic boron-containing zeolitic material of claim 1, wherein the one or more sources for B.sub.2O.sub.3 are selected from the group consisting of boric acid, boron oxide, a borate, a borate ester, and any combination thereof.

6. The synthetic boron-containing zeolitic material of claim 1, wherein a molar ratio of the one or more sources of YO.sub.2 to the one or more sources for B.sub.2O.sub.3 in the mixture ranges from 1:1 to 300:1.

7. The synthetic boron-containing zeolitic material of claim 1, wherein the one or more organotemplates are selected from the group consisting of a substituted (C.sub.5-C.sub.8)cycloalkylamines, an unsubstituted (C.sub.5-C.sub.8)cycloalkylamines, and any combination thereof.

8. The synthetic boron-containing zeolitic material of claim 1, wherein an amount of the one or more seed crystals in the mixture ranges from 0.05 to 80 weight-% based on 100 weight-% of YO.sub.2 in the one or more sources for YO.sub.2.

9. The synthetic boron-containing zeolitic material of claim 1, wherein the crystallizing (a) is conducted under solvothermal conditions.

10. The synthetic boron-containing zeolitic material of claim 1, wherein the process further comprises, after the crystallizing (a) and before the calcining (b) (i) isolating the layered precursor obtained in (a), (ii) optionally washing the layered precursor obtained in (i), and (iii) optionally drying the layered precursor obtained in (i) or (ii).

11. The synthetic boron-containing zeolitic material of claim 1, wherein the calcining (b) in the process is carried out at a temperature ranging from 300 to 900 C.

12. The synthetic boron-containing zeolitic material of claim 1, wherein the process further comprises, after the calcining (b) (iv) deboronating the boron-containing zeolitic material having an MWW framework structure obtained in (b) with a liquid solvent system, thereby obtaining a deboronated zeolitic material having an MWW framework structure.

13. The synthetic boron-containing zeolitic material of claim 1, wherein the one or more seed crystals comprise a zeolitic material having an MWW framework structure and/or a layered precursor of a zeolitic material having an MWW framework structure.

14. The synthetic boron-containing zeolitic material of claim 1, which has a lattice parameter for a c-axis measured from X-ray structure analysis ranging from 25.0 to 27.8 Angstrom.

15. A process, comprising performing ion-exchange and/or separation of a gas or liquid mixture with the synthetic zeolitic material having an MWW framework of claim 1 as a molecular sieve and/or as an adsorbent comprising contacting said mixture with said synthetic zeolitic material having an MWW framework during said performing.

16. A process, comprising performing at least one operation selected from the group consisting of hydrocarbon conversion, dehydration, epoxidation, epoxide ring opening, etherification, ammoxidation, and diesel oxidation catalysis with the synthetic zeolitic material having an MWW framework structure of claim 1 as a catalyst and/or as a catalyst component comprising contacting composition with said synthetic zeolitic material having an MWW framework during said performing.

17. The synthetic boron-containing zeolitic material of claim 1, wherein said one or more organotemplates represented by formula (I) are the only organotemplates.

Description

DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the XRD (X-Ray Diffraction) pattern of the calcined Al-MWW seed crystals obtained in reference Example 1, wherein the line pattern of MCM-22 has been included as a reference. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(2) FIG. 2 shows the XRD pattern of the B-MWW zeolitic product obtained in Example 1. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(3) FIG. 3 shows the nitrogen sorption isotherm of the calcined MWW zeolitic product obtained in Example 1. In the figure, the relative pressure p/p.sup.0 is plotted along the abscissa and the pore volume in cm.sup.3/g is plotted along the ordinate.

(4) FIG. 4 shows the .sup.11B MAS NMR of the calcined MWW product obtained according to Example 1. In the figure, the chemical shift in ppm is plotted along the abscissa and the relative intensity is plotted along the ordinate. Furthermore, a blow-up of the NMR for the range of ppm values between 5 and 10 ppm is shown, wherein again the chemical shift in ppm is plotted along the abscissa and the relative intensity in arbitrary units is plotted along the ordinate

(5) FIG. 5 shows the XRD pattern of the MWW zeolitic product obtained in Example 2, wherein the line pattern of the MWW framework structure has been included as a reference. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(6) FIG. 6 shows the XRD patterns of the MWW zeolitic products synthesized with a SiO.sub.2/B.sub.2O.sub.3 molar ratio of (a) 6.7, (b) 4.4, (c) 3.35, (d) 2.8, (e) 2.2, and (f) 1.9, according to Example 3. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(7) FIG. 7 shows the XRD patterns of the MWW zeolitic products synthesized with a CHA/SiO.sub.2 molar ratio of (a) 0.184, (b) 0.294, and (c) 0.514, according to Example 4. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(8) FIG. 8 shows the XRD patterns of the MWW zeolitic products synthesized with a Na.sub.2O/SiO.sub.2 molar ratio of (a) 0.052, (b) 0.105, (c) 0.131, (d) 0.166, and (e) 0.219, according to Example 5. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(9) FIG. 9 shows the XRD patterns of the products synthesized with a seed content of (a) 0 weight-%, (b) 2.5 weight-%, (c) 5 weight-%, and (d) 10 weight-%, according to Example 6. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(10) FIG. 10 shows the XRD pattern of the MWW zeolitic product obtained in Example 7. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(11) FIG. 11 shows the XRD pattern of the MWW zeolitic product obtained in Example 8. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

(12) FIG. 12 shows the XRD patterns of the three products obtained in Comparative Example 1. Specifically, FIG. 12(a) (top) is the XRD pattern of the product obtained with seed crystals and the organotemplate CHA; FIG. 12(b) (middle) is the XRD pattern of the product obtained with the organotemplate CHA but without seed crystals; FIG. 12(c) (bottom) is the XRD pattern of the product obtained with seed crystals but without the organotemplate CHA. In the figure, the diffraction angle 2 theta in is shown along the abscissa and the intensities are plotted along the ordinate.

EXAMPLES

(13) The particle size and the crystallinity of the zeolitic materials according to the present invention were determined by XRD analysis. The data were collected using a standard Bragg-Brentano diffractometer with a Cu-X-ray source and an energy dispersive point detector. The angular range of 2 to 70 (2 theta) was scanned with a step size of 0.02, while the variable divergence slit was set to a constant illuminated sample length of 20 mm. The data were then analyzed using TOPAS V4 software, wherein the sharp diffraction peaks were modeled using a Pawley fit containing a unit cell with the following starting parameters: a=14.4 Angstrom and c=25.2 Angstrom in the space group P6/mmm. These were refined to fit the data. Independent peaks were inserted at the following positions. 8.4, 22.4, 28.2 and 43. These were used to describe the amorphous content. The crystalline content describes the intensity of the crystalline signal to the total scattered intensity. Included in the model were also a linear background, Lorentz and polarization corrections, lattice parameters, space group and crystallite size.

(14) Solid-state NMR experiments were conducted by packing samples in ZrO.sub.2 rotors under ambient air. Measurements were performed using a 14.1 Tesla Bruker Avance III spectrometer equipped with a 4 mm Bruker MAS probe, at 6 kHz Magic Angle Spinning, at approximately 298 K sample temperature. .sup.11B direct polarization spectra were obtained using (/2)-pulse excitation with 6 s pulse width, with .sup.11B carrier frequency corresponding to 4 ppm in the spectrum. Signal was acquired for 34 ms, recycling ca. 1500 scans with a delay of 2 s. Spectra were processed using Bruker Topspin with 20 Hz exponential line broadening, manual phasing, and manual baseline correction over the full spectrum width. The .sup.11B resonance frequency was referenced to BF.sub.3.Et.sub.2O as an external zero standard.

Reference Example 1: Preparation of the Layered Precursor of Al-MWW and of Al-MWW Used as Seed Crystals

(15) 10.40 g of NaAlO.sub.2 (43 weight-% Na.sub.2O, 53 weight-% Al.sub.2O.sub.3) and 6.0 g of NaOH were dissolved in 1239.4 g of deionized water in a 2.5 L glass beaker. To this solution, 259 g of Ludox AS40 (40 weight-% SiO.sub.2) and 85.60 g of hexamethyleneimine were then added. The obtained gel has a molar composition of 40.28 SiO.sub.2:1.26 Al.sub.2O.sub.3:3.43 NaO:1606 H.sub.2O:20.13 hexamethyleneimine. Said gel was transferred into a 2.5 L autoclave, and heated up to 150 C. in 1 h under a rotating speed of 100 rpm. The crystallization was then carried out at 150 C. for 168 h.

(16) After the crystallization process, the white suspension obtained was adjusted with an HNO.sub.3 solution to reach a pH of about 6.0. Said suspension was then filtered, and washed with deionized water. The solid product, i.e., an Al-MWW precursor, was dried at 120 C. for 16 h.

(17) Calcination of the Al-MWW precursor affords the Al-MWW zeolite. The calcination may be carried out by heating up the Al-MWW precursor to 500 C. with a ramping rate of 1 C./min. and then maintaining it at 500 C. for 10 h. When doing so, 112 g of solid product was obtained.

(18) FIG. 1 shows the XRD pattern of the calcined product, from which it is apparent that said product has a MWW framework structure. The lattice constants a and c of the MWW product are determined to be 14.224 and 26.221 , respectively. The crystallinity of the MWW product is 82%, as measured from the XRD results. The average crystal size is measured to be 16.5 nm.

(19) Furthermore, as measured by the elemental analysis, the calcined MWW product contains 38 weight-% of Si, 2.5 weight-% of Al, 0.22 weight-% of Na, and less than 0.5 weight-% of carbon. Thus, the calcined MWW product displays an SiO.sub.2:Al.sub.2O.sub.3 molar ratio of 29.2.

Example 1: Preparation of B-MWW Using the Layered Precursor of Al-MWW as Seed Crystals

(20) 0.15 g of NaOH and 0.6 g of H.sub.3BO.sub.3 were dissolved in 8 g of deionized water. To this solution, 0.7 g of cyclohexylamine (CHA) was added and stirred for 30 min. Subsequently, 2.7 g of colloidal silica sol (GS30 silicate containing 30.5 weight-% SiO.sub.2, from Yuda Chemical Industry, China) was added dropwise to the solution, and followed by a stirring of 4 h at ambient temperature. The obtained gel has a molar composition of 0.131 Na.sub.2O:1 SiO.sub.2:0.354 B.sub.2O.sub.3:41 H.sub.2O:0.514 CHA. 0.04 g of (uncalcined) A-MWW layered precursor obtained according to Reference Example 1 (5 weight-% relative to SiO.sub.2 in the reaction mixture) was then added as seed crystals and stirred for 10 min. The mixture was transferred into a Teflon-lined autoclave and crystallized at 150 C. for 4 d under a rotation speed of 50 rpm. The crystallized product was filtrated, washed with deionized water, and dried at 100 C. for 4 h for affording the layered precursor of B-MWW. The dried product was then calcined at 500 C. for 6 h, thus affording the B-MWW zeolite.

(21) FIG. 2 shows the XRD pattern of the calcined product, from which it is apparent that said product has a MWW framework structure.

(22) The Si:B molar ratio of the obtained product is 32.8, as measured by the ICP. The yield of the product with respect to SiO.sub.2 is 98%.

(23) FIG. 3 shows the N.sub.2 sorption isotherm of the calcined MWW product. The BET specific surface area of said product according to DIN-ISO 9277:2010 is 356 m.sup.2/g. Furthermore, the product displays a micropore volume of 0.15 m.sup.3/g.

(24) FIG. 4 shows the .sup.11B MAS NMR of the calcined MWW product. The peak centered around 4 ppm that may be assigned to tetrahedral boron coordination (B[4]). In particular, no signals from trigonal coordination sites (B[3]) are observed in the spectrum, such that according to the NMR spectrum, boron contained in the sample is exclusively present in the framework structure, where it is tetrahedrally coordinated.

Example 2: Preparation of B-MWW Using the Layered Precursor of Al-MWW as Seed Crystals

(25) 22.5 g of NaOH and 90 g of H.sub.3BO.sub.3 were dissolved in 1335.7 g of deionized water. To this solution, 105 g of cyclohexylamine was added and stirred for 30 min. The pH of the obtained solution is 10.8. Subsequently, 309.2 g of Ludox AS40 (40 weight-% SiO.sub.2) was added to the solution, which was then stirred for 4 h. The obtained gel has a molar composition of 0.131 Na.sub.2O:1 SiO.sub.2:0.354 B.sub.2O.sub.3:41 H.sub.2O:0.514 CHA. 6 g of (uncalcined) Al-MWW precursor obtained according to Reference Example 1 (5 weight-% relative to SiO.sub.2 in the reaction mixture) were added as seed crystals into said gel, followed by a stirring of 10 min. The mixture was transferred into an autoclave and heated up to 150 C. in 1 h. The crystallization was carried out with a rotation speed of 150 rpm at 150 C. for 4 d. The solid product was filtrated, washed with deionized water, and dried at 120 C. for 10 h for affording the layered precursor of B-MWW. Finally, after a calcination at 650 C. for 5 h, 117 g of B-MWW zeolitic product was obtained.

(26) FIG. 5 shows the XRD pattern of the zeolitic product, from which it is apparent that the product has an MWW framework structure. The crystallinity of the MWW zeolite product is 76%. The average crystal size of the product is measured to be 22.5 nm. The lattice constants a and c of the MWW zeolite product are 14.087 and 26.109 , respectively.

(27) Furthermore, the BET surface area of the MWW zeolite product is determined to be 209 m.sup.2/g. The MWW zeolite product contains 44 weight-% of Si, 0.78 weight-% of B, 0.12 weight-% of Al, and less than 0.1 weight-% of C, as measured by the elemental analysis.

Example 3: Examining the Influence of the B.SUB.2.O.SUB.3 .Content

(28) Example 1 was repeated but with different SiO.sub.2:B.sub.2O.sub.3 molar ratios used for the gel precursor. SiO.sub.2:B.sub.2O.sub.3 molar ratios of 6.7, 4.4, 3.35, 2.8, 2.2 and 1.9 were employed for the synthesis in order to investigate the effect of different SiO.sub.2:B.sub.2O.sub.3 molar ratios on the crystallinity of the zeolitic products.

(29) FIG. 6 shows the XRD patterns of the zeolitic products obtained with different SiO.sub.2:B.sub.2O.sub.3 molar ratios in the gel precursor. It can be seen from the XDR patterns that the MWW zeolites prepared with a higher SiO.sub.2:B.sub.2O.sub.3 molar ratio displays a higher crystallinity based on the reflection intensity. For the zeolite prepared with a lower SiO.sub.2:B.sub.2O.sub.3 molar ratio, the reflection peaks associated with the MWW framework structure can still be resolved, but with a relatively less intensity.

(30) More specifically, it may be taken from FIG. 6 that sample a therein (synthesized with a SiO.sub.2/B.sub.2O.sub.3 ratio of 6.7) displays a high crystallinity in particular when compared to samples d-f prepared with low SiO.sub.2:B.sub.2O.sub.3 molar ratios. Notably, said sample a is measured to have lattice parameter a of 13.986 , and lattice parameter c of 25.969 Angstrom, based on its XRD pattern of FIG. 6.

Example 4: Examining the Influence of the Organotemplate Content

(31) Example 1 was repeated but with different CHA:SiO.sub.2 molar ratios used for the gel precursor. CHA:SiO.sub.2 molar ratios of 0.184, 0.294 and 0.514 were employed for the synthesis in order to investigate the effect of different CHA:SiO.sub.2 molar ratios on the crystallinity of the zeolitic products.

(32) FIG. 7 shows the XRD patterns of the zeolitic products obtained with different CHA:SiO.sub.2 molar ratios in the gel precursor. It can be seen from the XRD patterns that the MWW zeolite so prepared with a high CHA:SiO.sub.2 molar ratios such as 0.514 and 0.294 displays a relatively high crystallinity based on the intensity of the reflection peaks. For the zeolite prepared with a relatively low CHA:SiO.sub.2 molar ratio such as 0.184, the reflection peaks associated with the MWW framework structure can still be resolved, but with a relatively less intensity.

(33) More specifically, it may be taken from FIG. 7 that sample c therein (synthesized with a CHA/SiO.sub.2 ratio of 0.514) displays a high crystallinity when compared to the samples prepared with a lower CHA/SiO.sub.2 ratio. Notably, said sample c is measured to have lattice parameter a of 14.056 , and lattice parameter c of 27.010 , based on its XRD pattern of FIG. 7.

Example 5: Examining the Influence of the Na.SUB.2.O Content

(34) Example 1 was repeated but with different Na.sub.2O:SiO.sub.2 molar ratios used for the gel precursor. Na.sub.2O:SiO.sub.2 molar ratios of 0.052, 0.105, 0.131, 0.166 and 0.219 were employed for the preparation in order to investigate the effect of different Na.sub.2O:SiO.sub.2 molar ratios on the crystallinity of the zeolitic products.

(35) FIG. 8 shows the XRD patterns of the zeolitic products obtained with different Na.sub.2O:SiO.sub.2 molar ratios in the gel precursor. It can be seen from the XRD patterns that the MWW zeolite prepared with a high Na.sub.2O:SiO.sub.2 molar ratios such as 0.514 and 0.294 displays a relatively high crystallinity based on the intensity of the reflection peaks. For the zeolite prepared with a relatively low Na.sub.2O:SiO.sub.2 molar ratio such as 0.052, the intensity of the reflections peaks associated with the MWW framework structure is significantly decreased.

(36) More specifically, it may be taken from FIG. 8 that sample e therein (synthesized with a Na.sub.2O/SiO.sub.2 ratio of 0.219) displays a high crystallinity in particular when compared to samples a and b prepared with lower Na.sub.2O/SiO.sub.2 ratios. Notably, said sample e is measured to have lattice parameter a of 14.072 , and lattice parameter c of 26.077 , based on the XRD pattern of FIG. 8.

Example 6: Examining the Influence of the Seed Content

(37) Example 1 was repeated but with different contents of Al-MWW precursors in the gel precursor. 0 weight-%, 2.5 weight-%, 5 weight-% and 10 weight-% of Al-MWW precursors with respect to the SiO.sub.2 source of the colloidal silica were used for the samples in order to investigate the effect of seed contents on the crystallinity of the zeolitic products.

(38) FIG. 9 shows the XRD patterns of the products obtained with different seed contents in the gel precursor. It can be seen from the XDR patterns that the zeolite prepared with a high seed contents such as 5 weight-% and 10 weight-% displays a relatively high crystallinity based on the intensity of the reflection peaks. For the synthesis in the absence of seeds, the obtained product is amorphous, as demonstrated by the XRD pattern of sample a with 0 weight-% seeds in FIG. 9.

Example 7: Preparation of B-MWW Using the Al-MWW Zeolite as Seed Crystals

(39) Example 1 was repeated but by using the calcined Al-MWW zeolite as seed crystals (obtained from Reference Example 1). Since the Al-MWW seed crystals have been calcined under high temperatures, no additional organotemplate is introduced from the seed crystals, as supported by the very low carbon content of the seed crystals measured by the elemental analysis (see Reference Example 1).

(40) FIG. 10 shows the XRD pattern of the obtained product, from which it is apparent that said product has an MWW framework structure.

Example 8: Preparation of B-MWW Using the Uncalcined B-MWW Precursor as Seed Crystals

(41) 0.18 g of NaOH and 0.6 g of H.sub.3BO.sub.3 were dissolved in 9.9 g of deionized water. To this solution, 0.7 g of cyclohexylamine was added, and followed by a stirring of 30 min. Subsequently, 0.824 g of fine silica (fine-pored Silica Gel, from Qingdao Haiyang Chemical, China) was added to the solution, and stirring was continued for 4 h at ambient temperature. The obtained gel has a molar composition of 0.157 Na.sub.2O:1 SiO.sub.2:0.354 B.sub.2O.sub.3:41 H.sub.2O:0.514 CHA. 0.04 g of (uncalcined) B-MWW layered precursor obtained from Example 1 (5 weight-% relative to SiO.sub.2 in the reaction mixture) was then added as seed crystals into said gel, followed by a stirring of another 10 min. The mixture was transferred into a Teflon-lined autoclave and crystallized at 150 C. for 5 days under a rotating speed of 50 rpm. Finally, the crystallized product was filtrated, washed with deionized water, dried at 100 C. for 4 h, thus affording the layered precursor of B-MWW.

(42) FIG. 11 shows the XRD pattern of the product after calcination thereof, from which the typical pattern of the MWW framework structure is apparent.

Example 9: Preparation of B-MWW Using Li as the Alkali Metal

(43) Example 1 was repeated but using Li as the alkali metal in the synthetic gel having a molar composition of 0.156 Li.sub.2O:1 SiO.sub.2:0.22 B.sub.2O.sub.3:40 H.sub.2O:0.33 CHA, to which 5 weight-% of Al-MWW layered precursor relative to SiO.sub.2 of the gel was added. The obtained zeolitic product is characterized by a typical MWW framework structure, as measured by the XRD. Therefore, Li can also be used as the alkali metal for the synthesis of B-MWW zeolitic materials.

Comparative Example 1: Examining the Influence of Seed Crystals and Organotemplate

(44) Example 1 was repeated but using a molar composition of 0.131 Na.sub.2O:1 SiO.sub.2:0.354 B.sub.2O.sub.3:41 H.sub.2O:0.514 CHA for the synthetic gel, to which 5 weight-% of Al-MWW layered precursor relative to SiO.sub.2 of the gel was added. FIG. 12(a) shows the XRD pattern of the obtained zeolitic product, from which it is apparent that said product has a MWW framework structure.

(45) The above synthesis was repeated without adding seed crystals, or without adding the organotemplate CHA. Accordingly, FIGS. 12(b) and 12(c) show the XRD patterns of the final products obtained without seed crystals and without the organotemplate CHA, respectively. It may be taken from FIGS. 12(b) and 12(c) that both products are amorphous.

(46) A comparison of the XRD results of FIG. 12 shows that the use of a combination of seed crystals and the organotemplate is essential for the successful synthesis of the B-MWW zeolitic product. Therefore, the use of seed crystals but without the organotemplate, as well as the use of the organotemplate but without seed crystals, does not lead to the formation of the MWW zeolitic product.