One-Pot Synthesis of Transition Metal-Promoted Chabazites

Abstract

The invention provides methods for a one-pot synthesis of molecular sieves of the CHA-type. The method uses molecular and non-molecular sieves as sources of silicon and aluminum. A first OSDA is selected from tetraethylenepentamine (TEPA) and triethy-lenepentamine (TETA). The synthesis mixture comprises a first metal selected from copper, iron and zinc. Optionally, the synthesis mixture may furthermore comprise a second OSDA and/or a second metal selected from manganese, cesium, magnesium, calcium, strontium, barium, yttrium, titanium, zirconium, niobium, iron, zinc, silver, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and mixtures thereof. The molecular sieves of the CHA-type obtainable by the method can be used as SCR-catalytically active substances for the removal of nitrogen oxides from exhaust gases of combustion engines.

Claims

1. A one-pot synthesis method for the preparation of a molecular sieve of the CHA-type with targeted contents of copper, iron, zinc, and mixtures thereof as well as targeted contents of alkali metals, the method comprising the steps of: (I) providing the following components: (a) a non-molecular sieve source of silicon and/or a non-molecular sieve source of aluminum; (b) an alkali metal hydroxide AOH; (c) water; (d) a first organic structure-directing agent (OSDA1), which is tetraethylenepentamine (TEPA) and/or triethylenetetramine (TETA); (e) cations of a first metal Me selected from copper, iron, zinc, and mixtures thereof; (f) optionally a molecular sieve source of silicon and aluminum; and (g) optionally seed crystals of faujasite FAU.sub.Seed; and (h) optionally at least one salt of one or more second metals P, wherein P is different from the first metal Me; and (i) optionally a second organic structure-directing template (OSDA2); (II) synthesizing and crystallizing a molecular sieve of the CHA-type, comprising the steps of aa) mixing first portions of the components a), b) and c) according to step (I); ab) optionally adding component g) according to step (I) ac) crystallization of the mixture in a reactor; ad) adding second portions of the components a), b) and c) and components d) and e) and optionally h) and/or i) to the mixture obtained in step ac); ae) crystallization of the mixture obtained in step (II)(ad) in a reactor; or ba) mixing components a), b), c), d), e), f) and optionally h) and/or i) according to step (I); bb) crystallization of the mixture obtained in step (II)(ba) in a reactor; wherein the molar ratios of the components a), b) c), d), e), f) and optionally g), h) and/or i) of step (I) obtained after the completion of steps (II)(ad) and (II)(ba) are as follows: TABLE-US-00004 SiO.sub.2/Al.sub.2O.sub.3 about 10 to about 35 SiO.sub.2/AOH about 1 to about 2 SiO.sub.2/H.sub.2O about 0.03 to about 0.2 SiO.sub.2/FAU.sub.Seed about 40 to 400 OSDA1/SiO.sub.2 about 0.01 to about 0.1 Me/Al smaller than 0.5 Me/OSDA1 equal to or smaller than 1.0 P/Me 0 to 1, OSDA2/OSDA1 0 to 0.1; and wherein in step (II)(aa).sub.30 to 75 mol-% of the non-molecular sieve source of silicon, 80 to 100 mol-% of the non-molecular sieve source of aluminum, 40 to 100 mol-% of the alkali metal hydroxide AOH and 30 to 90 mol-% of water are added, and wherein in step (II)(ad).sub.70 to 25 mol-% of the non-molecular sieve source of silicon, 20 to 0 mol-% of the non-molecular sieve source of aluminum, 60 to 0 mol-% of the alkali metal hydroxide AOH and 70 to 10 mol-% of water are added, so that the mixture obtained after the completion of step (II)(ad) contains 100 mol % each of the non-molecular sieve source of silicon and aluminum, the alkali metal hydroxide AOH and water, and the molar ratios of the components a), b) c), d), e) and optionally g), h) and/or i) of step (I) obtained after the completion of step (II)(ad) are the ones given above; and (III) separating the molecular sieve of the CHA-type.

2. The method of claim 1, wherein the non-molecular sieve source of silicon is selected from silica, fumed silica, silicic acid, silicates, colloidal silica, tetraalkyl orthosilicates, and mixtures thereof.

3. The method of claim 1, wherein the non-molecular sieve source of aluminum is selected from alumina, boehmite, aluminates, and mixtures thereof.

4. The method of claim 1, wherein the non-molecular sieve source of silicon and aluminum is selected from precipitated silica-alumina, amorphous silica-alumina, kaolin, amorphous mesoporous materials, and mixtures thereof.

5. The method according to claim 1, wherein the alkali metal hydroxide cations in the alkali metal hydroxide AOH are a mixture of sodium cations with potassium and/or ammonium cations.

6. The method according to claim 1, wherein the cation of the first metal Me is a copper cation.

7. The method according to claim 1, wherein the molecular sieve source of silicon and aluminum is selected from FAU, LTL, GME, LEV, AEI, LTA, OFF, CHA, ERI, and mixtures thereof.

8. The method according to claim 1, wherein the at least one salt of one or more second metals P is selected from salts of manganese, cesium, magnesium, calcium, strontium, barium, yttrium, titanium, zirconium, niobium, iron, zinc, silver, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and mixtures thereof.

9. The method according to claim 1, wherein the at least one metal P is not introduced into the molecular sieve of the CHA type during the one-pot synthesis, but afterwards via liquid ion exchange, incipient wetness impregnation, or solid state ion exchange.

10. The method according to claim 1, wherein only an OSDA1 is provided, which is TEPA.

11. The method according to claim 1, wherein a part or all of the alkali ions and/or the part of the transition metal are removed from the molecular sieve after the separation of the molecular sieve of the CHA-type by ion-exchange.

12. The method of claim 1, comprising the further step of removing the OSDAs from the molecular sieve of the CHA-type by calcination, evaporation, decomposition, combustion, or a combination thereof.

13. A molecular sieve of the CHA-type which is made by the method according to claim 1.

14. A process for the removal of NOx from automotive combustion exhaust gases, which comprises using the molecular sieve of the CHA-type according to claim 13 as the SCR catalytically active material for the conversion of NOx.

15. A catalyzed substrate monolith comprising an SCR catalytically active material for the conversion of NOx for use in treating automotive combustion exhaust gases, wherein the SCR catalytically active material for the conversion of NOx is the molecular sieve of the CHA-type according to claim 13.

16. An exhaust gas purification system comprising a particulate filter coated with an SCR catalyst comprising the molecular sieve of the CHA-type according to claim 13.

17. An exhaust gas purification system comprising a PNA catalyst, wherein the PNA catalytically active material comprises the molecular sieve of the CHA-type according to claim 13 and at least one platinum group metal selected from ruthenium, rhodium, palladium, osmium, iridium, platinum, and mixtures thereof.

18. An exhaust gas purification system comprising an ASC catalyst, wherein the ASC catalytically active material comprises the molecular sieve of the CHA-type according to claim 13 and at least one platinum group metal selected from ruthenium, rhodium, palladium, osmium, iridium, platinum, and mixtures thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0227] FIG. 1: XRD of the Cu-CHA before ion-exchange according to Example 1.

[0228] FIG. 2: XRD of the Cu-CHA before ion-exchange according to Example 2.

[0229] FIG. 3: XRD of the Cu-CHA according to Example 3.

[0230] FIG. 4: XRD of the CuCe-La-CHA before ion-exchange according to Example 4.

[0231] FIG. 5: XRD of the CuMn-CHA before ion-exchange according to Example 5.

[0232] FIG. 6: XRD of the CuCe-CHA before ion-exchange according to Example 5.

[0233] FIG. 7: XRD of the Cu-CHA before ion exchange according to Comparative Example 1.

[0234] FIG. 8: XRD of the Cu-CHA before ion exchange according to Comparative Example 2.

[0235] FIG. 9: XRD of the Cu-CHA before ion exchange according to Comparative Example 3.

[0236] FIG. 10: XRD of the Cu-CHA before ion exchange according to Example 7.

[0237] FIG. 11: XRD of the Cu-CHA before ion exchange according to Example 9.

[0238] FIG. 12: XRD of the CuMn-CHA before ion exchange according to Example 10.

[0239] FIG. 13: XRD of the CuMn-CHA before ion exchange according to Example 12.

[0240] FIG. 14: XRD of the CuMn-CHA before ion exchange according to Example 13.

[0241] FIG. 15: XRD of the CuMn-CHA before ion exchange according to Example 14.

EMBODIMENTS

Example 1: Synthesis of Cu-CHA and Ion-Exchange

[0242] A 0.7M Cu/1M TEPA solution was made by adding 174.78 g of CuSO.sub.4*5H.sub.2O to 1000 mL distilled water. Afterwards 189.31 g TEPA was added under stirring. 10.35 g sodium hydroxide (VWR) was added to 126.93 ml of distilled water in a plastic beaker. To this solution, 506.54 g of sodium silicate and 242.19 g of the 0.7M Cu/1M TEPA solution was added. Afterwards 114.01 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/11.42 NaOH/0.7 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 1 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced was a CHA framework type with a SAR (SiO.sub.2/Al.sub.2O.sub.3) of 8.2, Cu/Al=0.33 and Na/Al=0.47.

[0243] The sample was suspended in a 1.39 M ammonium nitrate solution (10 mL solution/1 g of sample) and mixed for 4 hours at room temperature. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contained 0.28 Cu/Al and 0.07 Na/Al.

[0244] The XRD of Example 1 before ion-exchange is shown in FIG. 1.

Example 2: Synthesis of Cu-CHA and Ion-Exchange

[0245] 8.32 g sodium hydroxide (VWR) was added to 305.13 ml of distilled water in a plastic beaker. To this solution, 507.62 g of sodium silicate, 31.00 g CuSO.sub.4*5H.sub.2O and 33.67 g TEPA was added. Afterwards 114.25 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/11.14 NaOH/0.7 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 1 L autoclave and heated for 4 days at 130? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced is a CHA framework type with a SAR of 8.8, Cu/Al=0.33 and Na/Al=0.47.

[0246] The sample was suspended in a 1.39 M ammonium nitrate solution (10 mL solution/1 g of sample) and mixed for 4 hours at room temperature. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contained 0.28 Cu/Al and 0.07 Na/Al.

[0247] The XRD of Example 2 before ion-exchange is shown in FIG. 2.

Example 3: Synthesis of Cu-CHA

[0248] A 0.5M Cu/1M TEPA solution was made by adding 124.78 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0249] 53.52 g sodium hydroxide (VWR) was added to 693.65 ml of distilled water in a plastic beaker. To this solution, 2554.96 g of sodium silicate and 1170.79 g of the 0.5 M Cu/1M TEPA solution was added. Afterwards 527.00 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/11.5 NaOH/0.5 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The product SAR was 8.5, and the product contained 0.25 Cu/Al and 0.70 Na/Al.

[0250] The sample was suspended in a 5 M ammonium nitrate solution (10 mL solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h.

[0251] The sample was calcined under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contains 0.25 Cu/Al and 0.07 Na/Al.

[0252] The XRD of Example 3 is shown in FIG. 3.

Example 4: Synthesis of CuCe-La-CHA and Ion-Exchange

[0253] A solution was made by adding 174.78 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring. Afterwards 13.8 g of La(NO3)3.Math.6H2O and 13.77 g of Ce(NO.sub.3).sub.3*6H.sub.2O was added under stirring. 17.79 g sodium hydroxide (VWR) was added to 124.88 ml of distilled water in a plastic beaker. To this solution, 500.75 g of sodium silicate and 243.90 g of the CuCe-La-TEPA solution was added. Afterwards 112.71 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12.5 NaOH/0.7 Cu/0.025 Ce/0.031 La/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 1 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced has the CHA framework type. The product had a SiO.sub.2/Al.sub.2O.sub.3 ratio of 7.7, and contained 0.32 Cu/Al, 0.02 Ce/Al and 0.012 La/Al.

[0254] The sample was suspended in a 5 M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The final product contained 0.28 Cu/Al, 0.011 Ce/Al, 0.011 La/Al and 0.09 Na/Al.

[0255] The XRD of Example 4 before ion-exchange is shown in FIG. 4.

Example 5: Synthesis of CuMn-CHA and Ion-Exchange

[0256] A Cu-Mn-TEPA solution was made by adding 139.8264 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring. Afterwards 75.28 g of Mn(NO.sub.3).sub.2*4H.sub.2O was added under stirring.

[0257] 88.23 g sodium hydroxide (VWR) was added to 644.99 ml of distilled water in a plastic beaker. To this solution, 2483.82 g of sodium silicate and 1224.16 g of the Cu-Mn-TEPA solution was added. Afterwards 559.05 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12.5 NaOH/0.56 Cu/0.3 Mn/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM).

[0258] The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced was a CHA framework type with a SAR of 8.52, and contained 0.28 Cu/Al, and 0.14 Mn/Al.

[0259] The sample was suspended in a 5M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The final sample had a SAR of 8.44 and contained 0.28 Cu/Al, 0.13 Mn/Al and 0.12 Na/Al.

[0260] The XRD of Example 5 before ion-exchange is shown in FIG. 5.

Example 6: Synthesis of CuCe-CHA

[0261] A CuCe-TEPA solution was made by adding 262.1745 g of CuSO.sub.4*5H.sub.2O to 1500 ml distilled water. Afterwards 283.965 g TEPA was added under stirring. Afterwards 130.2 g of Ce(NO.sub.3).sub.3*6H.sub.2O was added under stirring.

[0262] 88.27 g sodium hydroxide (VWR) was added to 602.39 ml of distilled water in a plastic beaker. To this solution, 2484.78 g of sodium silicate and 1265.66 g of the CuCe-TEPA solution was added. Afterwards 559.26 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12.5 NaOH/0.7 Cu/0.2 Ce/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced was a CHA framework type with a SAR of 8.8, and contained 0.32 Cu/Al, and 0.09 Ce/Al and 0.68 Na/Al.

[0263] The sample was suspended in a 5M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The final sample had a SAR of 8.8 and contained 0.29 Cu/Al, 0.09 Ce/Al and 0.11 Na/Al.

[0264] The XRD of Example 6 before ion-exchange is shown in FIG. 6.

Comparative Example 1: Standard One-Pot Synthesis of Cu-CHA Followed by Ion Exchange

[0265] A 1M Cu-TEPA solution was made by adding 249.69 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0266] 71.33 g sodium hydroxide (VWR) was added to 604.49 ml of distilled water in a plastic beaker. To this solution, 2501.20 g of sodium silicate and 1260.02 g of the 1M Cu-TEPA solution was added. Afterwards 562.96 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12 NaOH/1 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced was a CHA framework type with a SAR of 8.8. The product contained 0.47 Cu/Al and 0.45 Na/Al.

[0267] The sample was suspended in a 5M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at 80? C. The material was recovered by filtration and dried at 60? C. for 16 h, this procedure was repeated another 2 times. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C.

[0268] Afterwards the zeolite was suspended in a 0.0375M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 24 hours at room temperature. The material was recovered by filtration and dried at 60? C. for 16 h. The product contained 0.24 Cu/Al and 0.04 Na/Al

[0269] The XRD of Comparative Example 1 before ion exchange is shown in FIG. 7.

Comparative Example 2: One-Pot Synthesis of Cu-CHA

[0270] A 1M Cu-TEPA solution was made by adding 249.69 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0271] 19.64 g sodium hydroxide (VWR) was added to 190.60 ml of distilled water in a plastic beaker. To this solution, 476.45 g of sodium silicate and 119.02 g of the 1M Cu-TEPA solution was added. Afterwards CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 31 SiO.sub.2/1 Al.sub.2O.sub.3/23 NaOH/1.1 Cu/1.1 TEPA/400 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 1 L autoclave and aged for 1 days at 95? C. under stirring with an anchor stirrer (140 RPM). Afterwards the autoclave was heated to 135? C. and remained at this temperature for 1.5 days. The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced was a CHA framework type with a SAR of 9.1 and contained 0.53 Cu/Al.

[0272] The sample was suspended in a 1M ammonium nitrate solution (100 ml solution/1 g of sample) and mixed for 4 hours at 80? C. The material was recovered by filtration and dried at 60? C. for 16 h, this procedure was repeated 2 times. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooling down to 25? C. Afterwards the zeolite was suspended in a 0.0075M ammonium nitrate solution (100 ml solution/1 g of sample) and mixed for 24 hours at room temperature. The material was recovered by filtration and dried at 60? C. for 16 h. The product contains 0.28 Cu/Al.

[0273] The XRD of Comparative Example 2 before ion exchange is shown in FIG. 8.

Comparative Example 3: One-Pot Synthesis of Cu-CHA

[0274] A 1M Cu-TEPA solution was made by adding 249.69 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0275] 100.12 g sodium hydroxide (VWR) was added to 852.03 ml of distilled water in a plastic beaker. To this solution, 2240.85 g of sodium silicate and 57.55 g of the 1M Cu-TEPA solution was added. Afterwards 249.46 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 31 SiO.sub.2/1 Al.sub.2O.sub.3/23 NaOH/1 Cu/1 TEPA/400 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and was heated to 140? C. for days under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced was a CHA framework type with a SAR of 8.32 and contained 0.44 Cu/Al.

[0276] The sample was suspended in a 2M ammonium nitrate solution (20 ml solution/1 g of sample) and mixed for 4 hours at 80? C. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contained 0.35 Cu/Al.

[0277] A small amount the zeolite was suspended in a 0.075M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 24 hours at room temperature. The material was recovered by filtration and dried at 60? C. for 16 h. The product contained 0.29 Cu/Al.

[0278] The XRD of Comparative Example 3 before ion exchange is shown in FIG. 9.

Example 7: Synthesis of Cu-CHA

[0279] A first gel was made by adding 31.83 g sodium hydroxide (VWR) to 299.03 ml of distilled water in a plastic beaker. To this solution, 235.88 g of Ludox AS-40 and 102.10 g of the sodium aluminate solution was added. The first gel had the following molar ratios: 10 SiO.sub.2/1 Al.sub.2O.sub.3/8.6 NaOH/180 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 1 L autoclave and heated for 14 hours at 95? C. under stirring with an anchor stirrer (140 RPM).

[0280] Next, a 2.1M/3M Cu-TEPA solution was made by adding 524.35 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 567.93 g TEPA was added under stirring.

[0281] Then, a second gel was made by adding 169.38 g of sodium silicate and 29.38 g of ZandoSil 30 (amorphous SiO.sub.2) to 22.36 mL distilled water. To this solution, 109.90 g of the 2.1M-3M Cu-TEPA solution was added. The second gel was homogenized by vigorous stirring for 30 minutes. After the first gel was cooled to 40? C., the autoclave was opened and the 2nd gel was added to the 1 L autoclave. The final gel has the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/11.5 NaOH/0.7 Cu/1 TEPA/248 H.sub.2O. The autoclave was heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced had a CHA framework type with a SAR of 7.6, and contained 0.31 Cu/Al and 0.49 Na/Al.

[0282] The sample was suspended in a 5M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooling down to 25? C.

[0283] The final product contained 0.25 Cu/Al and 0.06 Na/Al.

[0284] The XRD of the Cu-CHA before ion exchange is shown in FIG. 10.

Example 8: Synthesis of Cu-CHA

[0285] This Example was made in the same manner as Example 7 except for the ion exchange with ammonium nitrate: was suspended in a 1M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooling down to 25? C.

[0286] The final product contained 0.30 Cu/Al and 0.08 Na/Al.

Example 9: Synthesis of Cu-CHA

[0287] A first gel was made by adding 52.71 g sodium hydroxide (VWR) to 358.90 ml of distilled water in a plastic beaker. To this solution, 25.02 g of Gibbsite was added and the solution was boiled overnight. afterwards 230.40 g of Ludox AS-40 was added. The first gel had the following molar ratios: 10 SiO.sub.2/1 Al.sub.2O.sub.3/8.6 NaOH/180 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 1 L autoclave and heated for 14 hours at 95? C. under stirring with an anchor stirrer (140 RPM).

[0288] Next, a 1.5M/3M Cu-TEPA solution was made by adding 374.535 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 567.93 g TEPA was added under stirring.

[0289] Then, a second gel was made by adding 22.15 g of sodium hydroxide (VWR) to 20.97 mL distilled water. To this solution, 188.39 g of Ludox AS-40 was added. Afterwards 101.77 g of the 1.5M-3M Cu-TEPA solution was added. The second gel was homogenized by vigorous stirring for 30 minutes. After the first gel was cooled to 40? C., the autoclave was opened and the 2nd gel was added to the 1 L autoclave. The final gel has the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12.1 NaOH/0.5 Cu/1 TEPA/248 H.sub.2O. The autoclave was heated for 1.5 days at 142? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced is a CHA framework type with a SAR of 7.6, and contains 0.23 Cu/Al and 0.53 Na/Al.

[0290] The XRD of the Cu-CHA before ion exchange is shown in FIG. 11.

Example 10: Synthesis of CuMn-CHA

[0291] A Cu-Mn-TEPA (0.5M Cu/0.3M Mn/1M TEPA) solution was made by adding 124.845 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring. Afterwards 75.28 g of Mn(NO.sub.3).sub.2*4H.sub.2O was added under stirring.

[0292] 88.39 g sodium hydroxide (VWR) was added to 653.61 ml of distilled water in a plastic beaker. To this solution, 2488.11 g of sodium silicate and 1209.64 g of the Cu-Mn-TEPA (0.5M Cu/0.3M Mn/1M TEPA) solution was added. Afterwards 560.01 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel has the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12.5 NaOH/0.5 Cu/0.3 Mn/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM).

[0293] The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced is a CHA framework type with a SAR of 8.14, and contains 0.23 Cu/Al, 0.64 Na/Al and 0.15 Mn/Al.

[0294] The sample was suspended in a 5M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The final sample has a SAR of 7.6 and contains 0.24 Cu/Al, 0.11 Na/Al and 0.14 Mn/Al.

[0295] The XRD of the CuMn-CHA before ion exchange is shown in FIG. 12.

Example 11: Ion Exchange of CuMn-CHA

[0296] The as made product of example 10 was suspended in a 5M ammonium nitrate solution (10 ml solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. This procedure was repeated a 2nd time. The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooling down to 25? C. The final sample has a SAR of 7.6 and contains 0.23 Cu/Al, 0.06 Na/Al and 0.12 Mn/Al.

Example 12: Synthesis of CuMn-CHA

[0297] A 0.5M/1M Cu-TEPA solution was made by adding 124.78 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0298] 53.52 g sodium hydroxide (VWR) was added to 693.65 ml of distilled water in a plastic beaker. To this solution, 2554.96 g of sodium silicate and 1170.79 g of the 0.5M/1M Cu-TEPA solution was added. Afterwards 527.00 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel had the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/11.5 NaOH/0.5 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced is a CHA framework type with a SAR (SiO.sub.2/Al.sub.2O.sub.3) of 8.5, Cu/Al=0.25 & Na/Al=0.70.

[0299] The sample was suspended in a 5 M ammonium nitrate solution (10 mL solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h. This procedure was repeated a 2nd time 1.11 g Mn(NO.sub.3).sub.2*4H.sub.2O was added to 50 mL distilled water and afterwards 12.5 g of the sample was added (4 mL solution/1 g of sample) and mixed for 4 hours at 40? C. The material was recovered by filtration and dried at 60? C. for 16 h.

[0300] The sample was calcined under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contains 0.25 Cu/Al, 0.04 Na/Al and 0.04 Mn/Al.

[0301] The XRD of the CuMn-CHA before ion exchange is shown in FIG. 13.

Example 13: Synthesis of CuMn-CHA

[0302] A 0.5M/1M Cu-TEPA solution was made by adding 124.78 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0303] 53.67 g sodium hydroxide (VWR) was added to 702.02 ml of distilled water in a plastic beaker. To this solution, 2562.13 g of sodium silicate and 1153.82 g of the 0.5M/1M Cu-TEPA solution was added. Afterwards 526.50 g CBV-100 (Zeolyst) was added slowly upon stirring. The final gel has the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/11.5 NaOH/0.4 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced is a CHA framework type with a SAR (SiO.sub.2/AlO.sub.3) of 8.6, Cu/Al=0.20 and Na/Al=0.95.

[0304] 13.70 g Mn(NO.sub.3).sub.2*4H.sub.2O was added to 500 mL distilled water and afterwards 122.77 g of the sample was added (4 mL solution/1 g of sample) and mixed for 4 hours at 40? C. The material was recovered by filtration and dried at 60? C. for 16 h.

[0305] The sample was suspended in a 1 M ammonium nitrate solution (10 mL solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h

[0306] The sample was calcined under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contains 0.20 Cu/Al, 0.07 Na/Al and 0.13 Mn/Al.

[0307] The XRD of the CuMn-CHA before ion exchange is shown in FIG. 14.

Example 14: Synthesis of CuMn-CHA

[0308] A 0.5M/1M Cu-TEPA solution was made by adding 124.78 g of CuSO.sub.4*5H.sub.2O to 1000 ml distilled water. Afterwards 189.31 g TEPA was added under stirring.

[0309] 92.39 g sodium hydroxide (VWR) was added to 741.37 ml of distilled water in a plastic beaker. To this solution, 2443.13 g of sodium silicate and 1165.89 g of the 0.5M/1M Cu-TEPA solution was added. Afterwards 557.14 g of FAU (Si/Al=2.6) was added slowly upon stirring. The final gel has the following molar ratios: 18 SiO.sub.2/1 Al.sub.2O.sub.3/12.1 NaOH/0.5 Cu/1 TEPA/210 H.sub.2O. The resulting mixture was homogenized by vigorous stirring for 30 minutes. This mixture was transferred to a 5 L autoclave and heated for 1.5 days at 145? C. under stirring with an anchor stirrer (140 RPM). The solid product was recovered by filtration and washing, and was dried at 60? C. for 16 h. The zeolite produced is a CHA framework type with a SAR (SiO.sub.2/Al.sub.2O.sub.3) of 8.0, Cu/Al=0.25 and Na/Al=0.75.

[0310] The sample was suspended in a 5 M ammonium nitrate solution (10 mL solution/1 g of sample) and mixed for 4 hours at RT. The material was recovered by filtration and dried at 60? C. for 16 h.

[0311] The sample was calcinated under oxygen at 550? C. for 8 h (heating rate: 1? C./min) and cooled down to 25? C. The product contains 0.25 Cu/Al and 0.09 Na/Al.

[0312] 0.66 g of Mn(NO.sub.3).sub.2*4H.sub.2O was added to 50 mL distilled water and afterwards 12.19 g of the product was added (4 mL solution/1 g of sample) and mixed for 4 hours at 40? C. The material was recovered by filtration and dried at 60? C. for 16 h. The sample was calcined under oxygen at 550? C. for 2 h (heating rate: 1? C./min) and cooled down to 25? C. The product contains 0.20 Cu/Al, 0.06 Na/Al and 0.06 Mn/Al

[0313] The XRD of the CuMn-CHA before ion exchange is shown in FIG. 15.

[0314] As can be seen from the Examples according to the present invention and the Comparative Examples, the method for synthesizing chabazites according to the present invention provides CHA with a significantly lower ratio of transition metals Me to Al than methods according to the prior art. If the as-made chabazites according to the present invention are subsequently ion-exchanged with ammonium nitrate, the amounts of both the transition metals Me and the alkali metals A are reduced, but the content of the alkali metals A is reduced to a much greater extent than that of the transition metal Me. Further promoters P can be added with or without a reduction of the content of the transition metal Me.

Example 15: SCR Performance Data

[0315] The SCR performance after hydrothermal aging was determined by heating zeolite catalyst pellets to 650? C. with a heating rate of 5? C./min, and keeping them under air flow with a humidity of 12 vol. % for 100 h. Prior to this experiment, the powder was pelletized to a particle size between 500 and 710 ?m.

[0316] 140 mg of catalyst pellets (500-710 ?m) consisting of compressed zeolite powder are loaded in a quartz fixed bed tubular continuous flow reactor with on-line reaction product analysis. A typical gas composition for NH.sub.3SCR performance evaluation consists of 500 ppm NO.sub.x 750 ppm NH.sub.3, 5% O.sub.2 and 4% H.sub.2O with a flow of 100 L*Th.sup.?1. The catalyst first undergoes a pretreatment at 550? C., then the temperature is stepwise decreased from 550 to 150? C. with 50? C. intervals. An additional temperature plateau at 175? C. is foreseen. After reaching a stable temperature, an isothermal period of 5 minutes is foreseen for reaction product sampling at each temperature plateau.

[0317] NO.sub.x and N.sub.2O at the various temperatures was determined by means of on-line FTIR (Fourier Transform Infra-Red) spectrometer. The results are shown in Table 1.

TABLE-US-00003 TABLE 1 NOx conversion and N2O formation after hydrothermal aging 150? 175? 200? 250? 300? 350? 400? 450? 500? 550? C. C. C. C. C. C. C. C. C. C. NO.sub.x conversion (%) after 100 h650? C. Comparative 12.6 38.9 73.7 97.3 99.4 99.3 98.6 97.7 96.5 93.9 example 1 Example 3 12.5 39.0 74.1 97.3 99.3 99.2 98.7 98.1 96.9 94.0 Example 7 13.2 39.7 73.9 97.8 99.6 99.7 99.2 98.7 97.6 94.6 Example 12 11.9 37.2 72.2 96.9 99.3 99.3 98.6 97.6 96.1 92.1 Example 13 15.7 43.8 75.0 96.5 99.0 98.8 97.9 97.0 95.2 90.5 Example 14 13.6 40.9 74.2 96.6 99.0 98.8 98.1 97.4 96.0 92.5 N.sub.2O (ppm) after 100 h650? C. Comparative 1.2 2.4 5.0 11.5 17.7 15.9 13.6 16.1 21.8 27.8 example 1 Example 3 1.2 2.2 4.4 10.1 15.6 14.4 12.8 15.2 20.4 25.8 Example 7 1.2 2.3 4.7 10.7 15.9 14.8 13.0 15.0 20.1 25.3 Example 12 1.2 2.2 4.3 9.3 14.4 12.9 10.9 12.6 17.4 22.3 Example 13 1.2 2.1 3.8 8.3 11.6 9.8 9.0 11.1 14.8 18.7 Example 14 1.1 1.8 3.2 7.0 11.0 9.6 8.4 10.0 13.9 17.8