Crystalline zeolites with ERI/CHA intergrowth framework type

Abstract

The present invention relates to crystalline zeolites with an ERI/CHA intergrowth framework type and to a process for making said zeolites. The ERI content of the zeolites ranges from 10 to 85 wt.-%, based on the total weight of ERI and CHA. The zeolites may further comprise 0.1 to 10 wt.-% copper, calculated as CuO, and one or more alkali and alkaline earth metal cations in an amount of 0.1 to 5 wt.-%, calculated as pure metals. The process for making the zeolites with an ERI/CAH intergrowth framework type comprises a) the preparation of a first aqueous reaction mixture comprising a zeolite of the faujasite framework type, Cu-TEPA and a base M(OH), b) the preparation of a second aqueous reaction mixture comprising a silica source, an alumina source, an alkali or alkaline earth metal chloride, bromide or hydroxide, a quaternary alkylammonium salt and hexamethonium bromide, c) combining the two reaction mixtures, and d) heating the combination of the two reaction mixtures to obtain a zeolite with an ERI/CHA intergrowth framework type. The ERI/CHA intergrowth zeolite may subsequently be calcined. The zeolites according to the present invention are suitable SCR catalysts.

Claims

1. A process for making a crystalline aluminosilicate zeolite composition comprising an intergrowth of a CHA framework type material and an EM framework type material, said process comprising the following steps: a) preparing a first aqueous reaction mixture comprising a zeolite of the faujasite framework type, Cu-tetraethylenepentamine (Cu-TEPA) and at least one compound M(OH), wherein M is a sodium, potassium, or ammonium cation or a mixture thereof, b) preparing a second aqueous reaction mixture comprising a silica source, an alumina source, at least one salt AB or AB.sub.2, wherein A is chosen from lithium, sodium, potassium, rubidium, cesium, ammonium, magnesium, calcium, strontium, and barium and B is chosen from chloride, bromide, iodide, and hydroxide, and a quaternary alkylammonium salt having the general formula [NR1R2R3R4].sup.+X.sup.−, wherein R1, R2, R3, and R4 represent, independently from one another, a linear or branched alkyl group having 1 to 10 carbon atoms and X.sup.− is chosen from bromide, iodide, and hydroxide, and a hexamethonium bromide, iodide, or hydroxide, c) combining the two aqueous reaction mixtures, d) incubating the combination of the two aqueous reaction mixtures for at least 3 days at a temperature of 95° C. to 160° C. under dynamic conditions to form the crystalline aluminosilicate zeolite composition.

2. The process for making crystalline aluminosilicate zeolite composition according to claim 1, wherein the Cu-TEPA in step a) is used in an amount of 0.0001 mole/wt Cu-TEPA/zeolite of the faujasite framework type to 0.0016 mole/wt Cu-TEPA/zeolite of the faujasite framework type.

3. The process for making crystalline aluminosilicate zeolite composition according to claim 1, wherein the compound M(OH) in step a) is used in an amount of 0.001 mole/wt M(OH)/zeolite of the faujasite framework type to 0.025 mole/wt M(OH)/zeolite of the faujasite framework type.

4. The process for making crystalline aluminosilicate zeolite composition according to claim 1, wherein the zeolite composition obtained from step d) is subsequently calcined.

5. The process for making crystalline aluminosilicate zeolite composition according to claim 1, wherein the zeolite composition obtained after calcination is ion-exchanged in order to reduce the amount of alkali, alkaline earth metal, and copper cations.

6. A crystalline aluminosilicate zeolite composition comprising an intergrowth of a CHA framework type material and an ERI framework type material, said zeolite made by the process according to claim 2.

7. The crystalline aluminosilicate zeolite composition according to claim 6, wherein the EM content ranges from 10 to 85 wt.-%, based on the total weight of ERI and CHA combined.

8. The crystalline aluminosilicate zeolite composition according to claim 6, wherein the silica to alumina molar ratio ranges from 2 to 60.

9. The crystalline aluminosilicate zeolite composition according to claim 6, wherein the zeolite composition comprises copper in an amount of 0.1 to 10 wt.-%, calculated as CuO and based in on the total weight of the respective zeolite composition.

10. The crystalline aluminosilicate zeolite composition according to claim 9, wherein the copper to aluminum atomic ratio is in the range of between 0.002 to 0.5.

11. The crystalline aluminosilicate zeolite composition according to claim 6, wherein the zeolite composition comprises one or more alkali or alkaline earth metal cations selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, ammonium, magnesium, calcium, strontium, and barium in an amount of 0.1 to 5.0 wt.-%, calculated as pure metals and based on the total weight of the zeolites.

12. The crystalline aluminosilicate zeolite composition according to claim 6, wherein the mixture is incubated for at least 4 days.

13. The crystalline aluminosilicate zeolite composition according to claim 12, wherein the mixture is incubated for at least 7 days.

14. The crystalline aluminosilicate zeolite composition according to claim 12, wherein the first aqueous reaction mixture and/or the second aqueous reaction mixture are aged before mixing together.

15. The crystalline aluminosilicate zeolite composition according to claim 12, wherein the first aqueous reaction mixture and the second aqueous reaction mixture are aged for 48 hours before mixing together.

16. A washcoat comprising a crystalline aluminosilicate zeolite composition according to claim 6.

17. An SCR catalyst comprising a crystalline aluminosilicate zeolite composition according to claim 6.

18. An SCR catalyst comprising the washcoat according to claim 16.

19. An exhaust gas purification system containing an SCR catalyst according to claim 6.

20. A method of performing SCR catalysis, which comprises contacting an exhaust gas with a crystalline aluminosilicate zeolite composition according to claim 6 as the catalyst.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic overview of zeolites and their intergrowths as presented in Goossens et al., Eur J Inorg Chem 2001, 1167-1181.

(2) FIG. 2 shows X-Ray diffraction patterns of the calcined ERI/CHA zeolite intergrowth obtained in Embodiment 1, compared to zeolites with a pure CHA framework type according to Comparative Example 1 and a pure ERI framework type according to Comparative Example 3, respectively.

(3) FIG. 3 shows HRTEM images of the zeolite according to Embodiment 1 in two different magnifications. FIG. 3a shows the smaller and FIG. 3b the larger one of the magnifications. The TEM study was performed on the calcined samples. The crystals were dispersed in ethanol and treated by ultrasonication. A few droplets were put onto a holy carbon coated Cu grid. HRTEM images were made using a FEI Tecnai microscope operated at 200 kV.

(4) FIG. 4 shows the graphical representation of the NO.sub.x conversion test according to Embodiment 6. The solid line connects the measuring point at 450° C. and the return point at 150° C.

EMBODIMENTS

(5) Synthesis of Cu-TEPA

(6) The Cu-tetraethylenepentamine complex (Cu-TEPA) was synthesized by adding 37.9 g tetraethylenepentamine (0.2 mole, Sigma-Aldrich) to a solution consisting of 50 g CuSO.sub.4*5H.sub.2O (0.2 mole, Sigma-Aldrich) and 200 g of H.sub.2O (1 M solution) at room temperature upon stirring. This solution continued stirring for 2 h at room temperature.

Embodiment 1

(7) 3 g of zeolite Y with SAR=30 (Si/Al=15) (CBV-720, Zeolyst International) was suspended in 27 mL of a 1.2 M solution of sodium hydroxide at room temperature. To this solution 1.5 mL of a 1 M Cu-TEPA solution was added. The final gel has the following molar ratios: SiO.sub.2/0.033 Al.sub.2O.sub.3/0.033 Cu-TEPA/0.70 NaOH/34 H.sub.2O. This suspension was stirred for 15 min at room temperature and then kept static and heated at 95° C. for 48 h in a closed polypropylene bottle (PP bottle) and is referred to as aluminosilicate solution 1.

(8) Aluminosilicate solution 2 was prepared as follows: 0.28 g aluminium-tri-sec-butoxide (Fluka) was added upon stirring for 5 min at room temperature to 12.43 g tetraethylammonium hydroxide (35 wt.-%, Sigma-Aldrich) in a 60 mL PP bottle. This mixture was stirred mechanically for 10 minutes. To this solution, 5.46 g Ludox® AS-40 (Sigma-Aldrich) was added drop wise within 10 minutes at room temperature upon stirring and afterwards 1.65 g hexamethonium bromide (Acros) was added at once. Another 0.25 g of potassium chloride (LabChem) and 5.02 g of distilled water was added within 2 min. The final gel has the following molar ratios: SiO.sub.2/0.015 Al.sub.2O.sub.3/0.092 KCl/0.81 TEAOH/0.13 RBr/25 H.sub.2O where R is the hexamethonium organic template. This solution remained stirring for 24 h in the closed PP bottle at room temperature and forms a liquid gel. This gel was aged for another 48 h at room temperature without stirring.

(9) After the aging step, aluminosilicate solution 2 was added at once to aluminosilicate solution 1 at room temperature. The final gel has the following molar ratios: SiO.sub.2/0.025 Al.sub.2O.sub.3/0.39 NaOH/0.041 KCl/0.018 Cu-TEPA/0.36 TEAOH/0.0553 RBr/30 H.sub.2O where R is the hexamethonium organic template. The resulting mixture was homogenized by vigorous stirring for 15 minutes and afterwards transferred to a stainless steel autoclave. This mixture was heated for 168 h at 160° C. under dynamic conditions under autogenous pressure. The solid product was recovered by filtration and washing with 500 mL deionized water, and was dried at 60° C. for 8 to 16 h. The zeolite was calcined at 750° C. for 8 hours with a temperature ramp of 1° C./min. The zeolite produced has an X-ray diffraction pattern as shown in FIG. 2 with a SAR of 12.6 and 2.7 wt.-% CuO based on the total weight of the zeolite. The amount Na and K is 0.06 wt.-% and 0.25 wt.-%, respectively, calculated as pure metals and based on the total weight of the zeolite. The CHA content of the zeolite is 37 wt.-%, based on the total weight of ERI and CHA and is based on the analysis of the XRD pattern by identifying the relative amount of ERI and CHA in the ERI/CHA intergrowth.

(10) Table 1 shows the Bragg distance, the 2 theta position and the relative intensities of the zeolite obtained in this Embodiment prior to calcination.

(11) FIG. 3 shows HRTEM images of the zeolite according to Embodiment 1 in two different magnifications.

(12) TABLE-US-00001 TABLE 1 Bragg distance D (Å), 2theta position and relative intensities (I/I.sub.0) of the reflections of the zeolite obtained in Embodiment 1 D (Å) 2θ (°) I/I.sub.0 11.42 7.74 72 9.27 9.53 46 9.14 9.67 38 7.59 11.65 27 6.84 12.93 22 6.57 13.47 29 6.31 14.02 36 5.68 15.58 32 5.51 16.08 50 5.32 16.64 28 4.96 17.85 35 4.62 19.21 26 4.55 19.51 38 4.29 20.69 100 4.13 21.49 32 4.00 22.18 17 3.95 22.49 19 3.84 23.17 20 3.78 23.49 41 3.74 23.79 43 3.59 24.75 52 3.55 25.05 31 3.42 26.04 26 3.28 27.18 30 3.21 27.79 17 3.15 28.30 29 3.01 29.69 16 2.93 30.53 18 2.90 30.77 37 2.86 31.26 28 2.84 31.47 47 2.79 32.04 23 2.66 33.67 17 2.58 34.68 15 2.53 35.52 11 2.48 36.22 18 2.47 36.41 15 2.27 39.63 10 2.26 39.91 10 2.23 40.51 8 2.19 41.28 9 2.10 43.03 13 2.09 43.32 14 2.07 43.69 10 1.97 46.04 9 1.91 47.54 13 1.89 47.98 15 1.87 48.70 8 1.85 49.11 9 1.82 50.15 10 1.81 50.44 9 1.79 50.93 9 1.77 51.63 13 1.71 53.55 8 1.69 54.29 7 1.65 55.57 8 1.64 56.09 11 1.57 58.57 10 1.54 59.88 7 1.50 61.62 9 1.47 63.05 6 1.46 63.50 6 1.45 64.00 7 1.43 65.24 7 1.40 67.03 7 1.37 68.16 7 1.37 68.69 6 1.36 69.19 6

Embodiment 2

(13) 3 g of zeolite Y with SAR=30 (Si/Al=15) (CBV-720, Zeolyst International) was suspended in 27 mL of a 1.2 M solution of sodium hydroxide at room temperature. To this solution 1.5 mL of a 1 M Cu-TEPA solution was added. The final gel has the following molar ratios: SiO.sub.2/0.033 Al.sub.2O.sub.3/0.033 Cu-TEPA/0.70 NaOH/34 H.sub.2O. This suspension was stirred for 15 min and kept static and heated at 95° C. for 48 h in a closed PP bottle and is referred to as aluminosilicate solution 1.

(14) Aluminosilicate solution 2 was prepared as follows. 0.21 g aluminium-tri-sec-butoxide (Fluke) was added upon stirring for 5 min at room temperature to 9.32 g tetraethylammonium hydroxide (35 wt.-%, Sigma-Aldrich) in a 60 mL PP bottle. This mixture was stirred mechanically for 10 minutes. To this solution, 4.1 g Ludox AS-40 (Sigma-Aldrich) was added drop wise upon stirring within 10 min at room temperature and afterwards 1.24 g hexamethonium bromide (Acros) was added at once. Another 0.19 g of potassium chloride (LabChem) and 3.77 g of distilled water was added within 2 min. The final gel has the following molar ratios: SiO.sub.2/0.015 Al.sub.2O.sub.3/0.092 KCl/0.81 TEAOH/0.13 RBr/25 H.sub.2O where R is the hexamethonium organic template. This solution remained stirring for 24 h in the closed PP bottle at room temperature and forms a liquid gel. This gel was aged for another 48 h at room temperature without stirring.

(15) After the aging step, aluminosilicate solution 2 was added at once to aluminosilicate solution 1 at room temperature. The final gel has the following molar ratios: SiO.sub.2/0.026 Al.sub.2O.sub.3/0.44 NaOH/0.034 KCl/0.02 Cu-TEPA/0.30 TEAOH/0.047 RBr/31 H.sub.2O where R is the hexamethonium organic template. The resulting mixture was homogenized by vigorously stirring for 15 minutes and afterwards transferred to a stainless steel autoclave. This mixture was heated for 168 h at 160° C. under dynamic conditions and autogenous pressure. The solid product was recovered by filtration, washed with 500 mL deionized water, and dried at 60° C. for 8 to 16 h. The obtained zeolite has a SAR of 13.6 and 3.3 wt.-% CuO based on the total weight of the zeolite. The amount Na and K is 0.58 wt.-% and 1.0 wt.-%, respectively, calculated as pure metals and based on the total weight of the zeolite. The CHA content of the zeolite is 56 wt.-%, based on the total weight of ERI and CHA and is based on the analysis of the XRD pattern by identifying the relative amount of ERI and CHA in the ERI/CHA intergrowth.

Embodiment 3

(16) 3 g of zeolite Y with SAR=30 (Si/Al=15) (CBV-720, Zeolyst International) was suspended in 27 mL of a 1.2 M solution of sodium hydroxide at room temperature. To this solution 1.5 mL of a 1 M Cu-TEPA solution was added. The final gel has the following molar ratios: SiO.sub.2/0.033 Al.sub.2O.sub.3/0.033 Cu-TEPA/0.70 NaOH/34 H.sub.2O. This suspension was stirred for 15 min and kept static and heated at 95° C. for 48 h in a closed PP bottle and is referred to as aluminosilicate solution 1.

(17) Aluminosilicate solution 2 was prepared as follows. 0.28 g aluminium-tri-sec-butoxide (Fluka) was added upon stirring to 12.43 g tetraethylammonium hydroxide (35 wt.-%, Sigma-Aldrich) in a 60 mL PP bottle. This mixture was stirred mechanically for 10 minutes. To this solution, 5.46 g Ludox AS-40 (Sigma-Aldrich) was added drop wise upon stirring for 5 min at room temperature and afterwards 1.65 g hexamethonium bromide (Acros) was added at once. Another 0.25 g of potassium chloride (LabChem) and 5.02 g of distilled water was added within 2 min. The final gel has the following molar ratios: SiO.sub.2/0.015 Al.sub.2O.sub.3/0.092 KCl/0.81 TEAOH/0.13 RBr/25 H.sub.2O where R is the hexamethonium organic template. This solution remained stirring for 24 h in the closed PP bottle at room temperature and forms a liquid gel. This gel was aged for another 48 h at room temperature without stirring.

(18) After the aging step, aluminosilicate solution 2 was added at once to aluminosilicate solution 1 at room temperature. The final gel has the following molar ratios: SiO.sub.2/0.025 Al.sub.2O.sub.3/0.39 NaOH/0.041 KCl/0.02 Cu-TEPA/0.36 TEAOH/0.055 RBr/30 H.sub.2O where R is the hexamethonium organic template. The resulting mixture was homogenized by vigorously stirring for 15 minutes and heated for 504 h at 95° C. under static conditions and autogenous pressure. The solid product was recovered by filtration and washing with 500 mL deionized water, and was dried at 60° C. for 8 to 16 h. The obtained zeolite has a SAR of 12.9 and 3.9 wt.-% CuO based on the total weight of the zeolite. The amount Na and K is 0.93 wt.-% and 1.7 wt.-%, respectively, calculated as pure metals and based on the total weight of the zeolite. The CHA content of the zeolite is 46 wt.-%, based on the total weight of ERI and CHA and is based on the analysis of the XRD pattern by identifying the relative amount of ERI and CHA in the ERI/CHA intergrowth.

Embodiment 4

(19) 3 g of zeolite Y with SAR=12 (Si/Al=6) (CBV-712, Zeolyst International) was suspended at room temperature in a mixture of 14 mL of a 1.2 M solution of sodium hydroxide and 13 mL of a 1.2 M solution of ammonium hydroxide. To this solution 1.5 mL of a 1 M Cu-TEPA solution was added. The final gel has the following molar ratios: SiO.sub.2/0.083 Al.sub.2O.sub.3/0.036 Cu-TEPA/0.41 NaOH/0.38 NH.sub.4OH/38 H.sub.2O. This suspension was stirred for 15 min and kept static and heated at 95° C. for 48 h in a closed PP bottle and is referred to as aluminosilicate solution 1.

(20) Aluminosilicate solution 2 was prepared as follows. 0.28 g aluminium-tri-sec-butoxide (Fluka) was added upon stirring to 12.43 g tetraethylammonium hydroxide (35 wt.-%, Sigma-Aldrich) in a 60 mL PP bottle. This mixture was stirred mechanically for 10 minutes. To this solution, 5.46 g Ludox AS-40 (Sigma-Aldrich) was added drop wise upon stirring within 5 min at room temperature and afterwards 1.65 g hexamethonium bromide (Acros) was added at once. Another 0.25 g of potassium chloride (LabChem) and 5.02 g of distilled water was added within 2 min. The final gel has the following molar ratios: SiO.sub.2/0.015 Al.sub.2O.sub.3/0.092 KCl/0.81 TEAOH/0.13 RBr/25 H.sub.2O where R is the hexamethonium organic template. This solution remained stirring for 24 h in the closed PP bottle at room temperature and forms a liquid gel. This gel was aged for another 48 h at room temperature without stirring.

(21) After the aging step, aluminosilicate solution 2 was added at once to aluminosilicate solution 1 at room temperature. The final gel has the following molar ratios: SiO.sub.2/0.05 Al.sub.2O.sub.3/0.22 NaOH/0.20 NH.sub.4OH/0.043 KCl/0.019 Cu-TEPA/0.38 TEAOH/0.059 RBr/32 H.sub.2O where R is the hexamethonium organic template. The resulting mixture was homogenized by vigorously stirring for 15 minutes and afterwards transferred to a stainless steel autoclave. This mixture was heated for 168 h at 160° C. under static conditions and autogenous pressure. The solid product was recovered by filtration, washed with 500 mL deionized water, and dried at 60° C. for 8 to 16 h. The obtained zeolite has a SAR of 14.4 and 1.7 wt.-% CuO based on the total weight of the zeolite. The amount Na and K is 0.37 wt.-% and 2.1 wt.-%, respectively, calculated as pure metals and based on the total weight of the zeolite. The CHA content of the zeolite is 20 wt.-%, based on the total weight of ERI and CHA and is based on the analysis of the XRD pattern by identifying the relative amount of ERI and CHA in the ERI/CHA intergrowth.

Embodiment 5

(22) 5 g zeolite obtained as described in embodiment 4 is suspended in a 500 mL aqueous solution containing 0.5 M NH.sub.4Cl. This mixture is heated at boiling point for 4 hours under reflux condition upon stirring. The zeolite is recovered by filtration and washing with 1 L deionized water, and was dried at 60° C. for 8 to 16 h. Afterwards, this procedure is repeated two times. The amount Na and K was decreased to 0.03 wt.-% and 0.41 wt.-%, calculated as pure metals and based on the total weight of the zeolite. The Cu content was lowered to 0.19 wt.-%, calculated as CuO and based on the total weight of the zeolite.

Embodiment 6

(23) Catalyst pellets consisting of compressed zeolite powder obtained in Embodiment 1 are loaded in a quartz fixed bed tubular continuous flow reactor with on-line reaction product analysis. The catalyst first undergoes a pretreatment under simulated air flow conditions, i.e. 5% O.sub.2 and 95% N.sub.2, at 450° C., the highest temperature of the catalytic testing. After pretreatment, the catalyst temperature is decreased to 150° C. A typical gas composition for NH.sub.3-SCR performance evaluation consists of 500 ppm NO, 450 ppm NH.sub.3, 5% O.sub.2, 2% CO.sub.2, 2.2% H.sub.2O. The gas hourly space velocity (GHSV) will be fixed at 30 000 h.sup.−1, obtained with 0.5 cm.sup.3 catalyst bed and a gas flow of 250 mL/min. The temperature will be stepwise increased from 150 to 450° C. with fixed temperature ramps, and 50° C. intervals. Isothermal periods of 60 to 120 minutes are foreseen before reaction product sampling at each temperature plateau. A return point to 150° C. enables detection of degradation of catalytic performance during the testing.

(24) Table 2 shows the NO.sub.x conversion for each temperature measured.

(25) FIG. 4 shows the graphical representation of the NO.sub.x conversion test.

(26) TABLE-US-00002 TABLE 2 NO.sub.x conversion of the zeolite powder obtained in Embodiment 1. The gas composition consisted of 500 ppm NO, 450 ppm NH.sub.3, 5% O.sub.2, 2% CO.sub.2, 2.2% H.sub.2O, and the gas hourly space velocity (GHSV) was fixed at 30 000 h−1, obtained with 0.5 cm3 catalyst bed and a gas flow of 250 mL/min. The bottom row of the table shows the NO.sub.x conversion at the return point of 150° C. The bottom row demonstrates that there was no degradation of catalytic performance during the testing as the NO.sub.x conversion did not decrease in comparison to the start. The start was also at 150° C., see top row, and the NO.sub.x conversion rates at the start and at the end (top and bottom row) were almost identical. Temperature (° C.) NO.sub.x conversion (%) 150 79.4 175 90.9 200 93.8 250 85.9 300 85.6 350 84.7 400 83.0 450 82.0 150 79.9

COMPARATIVE EXAMPLE 1

(27) 3 g of zeolite Y with SAR=30 (Si/Al=15) (CBV-720, Zeolyst International) was suspended in 27 mL of a 1.2 M solution of sodium hydroxide at room temperature. To this solution 1.5 mL of a 1 M Cu-TEPA solution was added. The final gel has the following molar ratios: SiO.sub.2/0.033 Al.sub.2O.sub.3/0.033 Cu-TEPA/0.70 NaOH/34 H.sub.2O. This suspension was stirred for 15 min at room temperature and kept static and heated at 95° C. for 456 h in a closed PP bottle. The zeolite produced has an X-ray diffraction pattern corresponding to a pure CHA framework type.

COMPARATIVE EXAMPLE 2

(28) 0.28 g aluminium-tri-sec-butoxide (Fluka) was added upon stirring to 12.43 g tetraethylammonium hydroxide (35 wt.-%, Sigma-Aldrich) in a 60 mL PP bottle at room temperature. This mixture was stirred mechanically for 10 minutes. To this solution, 5.46 g Ludox AS-40 (Sigma-Aldrich) was added drop wise upon stirring within 5 min at room temperature and afterwards 1.65 g hexamethonium bromide (Acros) was added at once. Another 0.25 g of potassium chloride (LabChem) and 5.02 g of distilled water was added slowly. The final gel has the following molar ratios: SiO.sub.2/0.015 Al.sub.2O.sub.3/0.092 KCl/0.81 TEAOH/0.13 RBr/25 H.sub.2O where R is the hexamethonium organic template. This solution remained stirring for 24 h in the closed PP bottle at room temperature and forms a liquid gel. This mixture was heated for 168 h at 160° C. under dynamic conditions under autogenous pressure. The solid product was recovered by filtration and washing with 500 mL deionized water and was dried at 60° C. overnight. The zeolite produced has an X-ray diffraction pattern corresponding to crystalline material but not as an ERI framework type. The product obtained was a mixture of different zeolite frameworks.

COMPARATIVE EXAMPLE 3

(29) 0.28 g aluminium-tri-sec-butoxide (Fluka) was added upon stirring to 12.43 g tetraethylammonium hydroxide (35 wt.-%, Sigma-Aldrich) in a 60 mL PP bottle at room temperature. This mixture was stirred mechanically for 10 minutes. To this solution, 5.46 g Ludox AS-40 (Sigma-Aldrich) was added drop wise upon stirring within 5 min at room temperature and afterwards 1.65 g hexamethonium bromide (Acros) was added at once. Another 0.25 g of potassium chloride (LabChem) and 5.02 g of distilled water was added slowly within 10 min at room temperature. The final gel has the following molar ratios: SiO.sub.2/0.015 Al.sub.2O.sub.3/0.092 KCl/0.81 TEAOH/0.13 RBr/25 H.sub.2O where R is the hexamethonium organic template. This solution remained stirring for 24 h in the closed PP bottle at room temperature and forms a liquid gel. This mixture was heated for 336 h at 100° C. under dynamic conditions under autogenous pressure. The solid product was recovered by filtration and washing with 500 mL deionized water, and was dried at 60° C. for 8 to 16 h. The zeolite produced has an X-ray diffraction pattern corresponding to a pure ERI framework type.

(30) Table 2 shows the Bragg distances, the 2 theta positions and the relative intensities of the zeolite obtained in Embodiment 1 after to calcination, i.e. the ERI/CHA zeolite according to the present invention, as well as the corresponding values of the CHA framework type zeolite according to Comparative Example 1, and of the ERI framework zeolite according to Comparative Example 3, respectively.

(31) TABLE-US-00003 TABLE 3 Position and relative intensities of reflections of the calcined ERI/CHA zeolite according to Embodiment 1 compared to zeolites with pure ERI or CHA framework type as obtained in Comparative Examples 3 and 1, respectively CHA framework ERI framework type type ERI/CHA Comparative Comparative Embodiment 1 Example 1 Example 3 2θ (°) I/I.sub.0 2θ (°) I/I.sub.0 2θ (°) I/I.sub.0 7.77 81 7.85 100 9.56 100 9.54 79 9.76 53 9.77 20 11.72 42 11.82 23 12.97 54 12.95 31 13.51 69 13.62 44 14.08 50 14.04 17 14.08 50 14.21 20 15.61 38 15.72 12 16.13 47 16.08 40 16.69 38 16.74 13 17.91 43 17.88 29 19.31 39 19.17 13 19.31 39 19.39 15 19.57 37 19.71 18 20.75 95 20.71 100 20.75 95 20.84 22 21.54 41 21.64 19 22.14 30 22.15 15 22.57 31 22.49 16 23.26 39 23.17 26 23.58 43 23.67 26 23.86 50 23.99 31 24.89 62 25.07 37 25.14 44 25.08 37 26.12 36 26.05 29 27.28 39 27.42 21 27.87 28 27.81 17 28.41 40 28.31 17 28.41 40 28.59 20 30.86 51 30.78 63 31.39 39 31.22 32 31.58 49 31.75 28

(32) Some of the 2Θ values of the ERI/CHA zeolite according to Embodiment 1 are listed twice in the above table 3 because they correspond to 2Θ values of pure CHA and pure ERI, respectively. These 2Θ values are listed in table 4

(33) TABLE-US-00004 TABLE 4 2Θ values of the ERI/CHA intergrowth according to the present invention and the respective 2Θ values of pure CHA and pure ERI. 2Θ ERI/CHA intergrowth (°) 2Θ CHA (°) 2Θ ERI (°) 14.08 14.21 14.04 19.31 19.39 19.17 20.75 20.84 20.71 28.41 28.59 28.31