Process for the direct synthesis of Cu-SAPO-34

Abstract

A process for the direct synthesis of Cu-SAPO-34 comprising at least the steps: preparation of a mixture of water, at least one silicon source, at least one Al source, at least one P source, at least one Cu source, at least one 0SDA1 (any polyamine), and at least one OSDA2 source (where OSDA2 is any organic molecule capable of directing the synthesis of SAPO 34); and where the final synthesis mixture has the molar composition: a Si:0.5 Al:c Cu:d OSDA1:e OSDA2:f H2O wherein a is in the range from 0.01 to 0.3; b is in the range from 0.2 to 0.49; c is in the range from 0.001 to 0.6; d is in the range from 0.001 to 0.6; e is in the range from 0.001 to 2; f is in the range 1 to 200; hydrothermal treatment of the mixture at 80200 C. until formation of the crystalline material, and recovery of the crystalline material.

Claims

1. Process for the direct synthesis of Cu-SAPO-34 comprising the steps of: (i) preparing a synthesis mixture containing water, at least one silicon source, at least one Al source, at least one P source, at least one Cu source, at least one OSDA1 wherein the OSDA1 is a polyamine selected from the group of tetraethylenepentamine, triethylenetetramine, 1,4,8,11-tetraazacyclotetradecane or 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, and at least one OSDA2, wherein the OSDA2 is an organic compound different from polyamine and capable of directing the synthesis of the SAPO-34 and a final synthesis mixture having a molar composition of: a Si:0.5 Al:b P:c Cu:d OSDA1:e OSDA2:fH2O where a is in the range from 0.01 to 0.3; where b is in the range from 0.2 to 0.49; where c is in the range from 0.001 to 0.6; where d is in the range from 0.001 to 0.6; where e is in the range from 0.001 to 2; where f is in the range from 1 to 200; (ii) hydrothermally treating the mixture at 80-200 C. until formation of crystalline material, (iii) recovering of the crystalline material, (iv) removing OSDA1 and OSDA2 from the crystalline material.

2. The process according to claim 1, wherein the OSDA1 comprises at least one of tetraethylenepentamine, triethylenetetramine, 1,4,8,11-tetraazacyclotetradecane, 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane.

3. The process of claim 1, wherein the OSDA2 comprises at least one of diethylamine, dipropylamine, triethanolamine, cyclohexylamine, morpholine, salts of tetraethylammonium, pidepiridine.

4. The process of claim 1, wherein the final synthesis mixture comprises the following molar compositions: a Si:0.5 Al:b P:c Cu:d OSDA1:e OSDA2:fH2O wherein a is in the range from 0.05 to 0.3; wherein b is in the range from 0.2 to 0.45; wherein c is in the range from 0.01 to 0.4; wherein d is in the range from 0.01 to 0.4; wherein e is in the range from 0.1 to 1; and wherein f is in the range from 2 to 100.

5. The process of claim 1, wherein the crystallization step (ii) is performed in an autoclave, under static or dynamic conditions.

6. The process of claim 1, wherein the temperature in step (ii) is in the range of 100 to 200 C.

7. The process of claim 1, wherein the crystallization time in step (ii) is in the range from 6 hours to 50 days.

8. The process of claim 1, wherein crystals of a CHA zeolite or zeotype are added as seeds, in quantities up to 25% by weight with respect to the total amount of oxides in the synthesis mixture before or during the crystallization of Cu-SAPO-34.

9. The process of claim 1, wherein the elimination of OSDA 1and OSDA2 in step (iv) from the crystalline material is performed by extraction and/or thermal treatment at temperatures above 25 C., during a period of time between 2 minutes and 25 hours.

10. The process of claim 1, wherein the pH value of the synthesis mixture is below 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: PXRD patterns of the as-prepared and calcined form of Cu-SAPO-34 of Example 54.

(2) FIG. 2 shows the SEM image of the Cu-SAPO-34 material of Example 54, revealing a crystal size of 6-8 m.

(3) FIG. 2: SEM image of Cu-SAPO-34 of Example 54.

(4) FIG. 3 shows the UV-Vis spectra of the Cu-TEPA complex in solution (a) and the as-prepared Cu-SAPO-34 of Example 54 (b). Both spectra exhibit a strong band at 270 nm, revealing that Cu-TEPA complex is retained after crystallization, leading the presence of Cu2+extra-framework cations after organic removal.

(5) FIG. 3: UV-Vis spectra of Cu-TEPA complex in solution (a), and as-prepared Cu-SAPO-34 of Example 54.

Example 58

Direct synthesis of Cu-SAPO-34 using a cyclic polyamine for the formation of Cu-complex (Cu-1,4,8,11-tetraazacyclotetradecane, Cu-cyclam) in combination with a cooperative OSDA (diethylamine, DEA)

(6) The present examples attempted to control the Cu-loading into the Cu-SAPO-34, but using a different polyamine in the formation of Cu-complex. In the present example, the cyclic polyamine 1,4,8,11-tetraazacyclotetradecane, also called cyclam, is introduced in the synthesis gel, together with a cooperative OSDA, such as diethylamine (DEA).

(7) A typical preparation of present example was as follows: as a first step, the Cu-complex molecule was prepared. To do that, 100 mg of 20% wt of an aqueous solution of copper (II) sulfate (98% wt, Alfa) was mixed with 25 mg of 1,4,8,11-tetraazacyclotetradecane (cyclam, 98% wt, Aldrich), and kept under stirring during 2 hours. As a second step, 282 mg of distilled water and 128 mg of phosphoric acid (85% wt, Aldrich) were added, and stirred during 5 minutes. Afterwards, 94 mg of alumina (75% wt, Condea) and 75 mg of silica (Ludox AS40 40% wt, Aldrich) sources were introduced in the gel mixture. Finally, 82 mg of diethylamine (99% wt, Aldrich) was added in the gel and maintained under stirring during 30 minutes. The molar gel compositions were the next: P/Al=0.8; Si/(P+Al)=0.2; Cu-cyclam/(Al+P)=0.05; DEA/(Si+Al)=0.45; H2O/(Si+Al)=10. Once the synthesis gel was prepared, it was transferred to an autoclave with a Teflon liner, and heated to a temperature of 150 C. during 5 days under static conditions. The sample after hydrothermal crystallization was filtered and washed with abundant distilled water, and finally dried at 100 C.

(8) The sample was calcined at 550 C. in air in order to remove the organic moieties precluded inside of the microporous material during the crystallization process.

Example 59

Characterization of Cu-SAPO-34 synthesized in the Example 58

(9) The sample synthesized in Example 58 has been characterized by PXRD, scanning electron microscopy (SEM), and UV-Vis spectroscopy. Figure 4 shows the PXRD of the Cu-SAPO-34 material of Example 58 in its as-prepared and calcined form, confirming the structure and high-crystallinity of SAPO-34 before and after calcination.

(10) FIG. 4: PXRD patterns of the as-prepared and calcined form of Cu-SAPO-34 of Example 58.

(11) FIG. 5 shows the SEM image of the Cu-SAPO-34 material of Example 58, revealing a crystal size of 10-15 m. FIG. 5: SEM image of Cu-SAPO-34 of Example 58.

(12) FIG. 6 shows the UV-Vis spectrum of the as-prepared Cu-SAPO-34 of Example 58. This spectrum exhibits a strong band at 270 nm, revealing that Cu-cyclam complex is retained after crystallization, leading the presence of Cu2+ extra-framework cations after organic removal.

(13) FIG. 6: UV-Vis spectrum of as-prepared Cu-SAPO-34 of Example 58

Example 60

Preparation of Cu-exchanged SAPO-34

(14) The procedure used for the synthesis of SAPO-34 was: 2.05 g of phosphoric acid (85% wt, Aldrich) was diluted in 8.7 g of distilled water, stirring the resultant solution during 5 minutes. Afterwards, 1.5 g of alumina (75% wt, Condea) and 1.04 g of silica (Ludox AS40 40% wt, Aldrich) were introduced in the gel mixture. Finally, 1.65 g of diethylamine (99% wt, Aldrich) was added in the gel, maintaining under agitation during 30 minutes. Once the synthesis gel was prepared, it was transferred to an autoclave with a Teflon liner, and heated to a temperature of 200 C. during 72 hours under static conditions. The sample after hydrothermal crystallization was filtered and washed with abundant distilled water, and finally dried at 100 C. The sample was characterized by PXRD, showing the characteristic PXRD pattern of SAPO-34. The sample was calcined at 550 C. in air in order to remove the organic moieties precluded inside of the microporous material during the crystallization process.

(15) In order to perform the Cu ion exchange on this SAPO-34 material, the calcined sample was first washed with NaNO3 (0.04M), and afterwards, the sample was exchanged at room temperature with a Cu(CH3CO2)2 solution (solid/liquid ratio of 10 g/L). Finally, the sample was filtered and washed with distilled water, and calcined at 550 C. for 4 h.

Example 61

Catalytic tests on SCR of NOx Over Different Cu-SAPO-34 Synthesized by the Present Invention

(16) The activity of the samples for the catalytic reduction of NOx was studied in a fixed bed, quartz tubular reactor of 2.2 cm of diameter and 53 cm of length. In a typical experiment, the catalyst was prepared with a particle size of 0.25-0.42 mm. It was introduced in the reactor, heated up to 550 C. (see reaction conditions in Table IX) and maintained at these temperatures for one hour under nitrogen flow. After that the desired reaction temperature was set and the reaction feed admitted. The SCR of NOx was studied using NH3 as reductor. The NOx present in the outlet gases from the reactor were analyzed continuously by means of a chemiluminiscence detector (Thermo 62C).

(17) TABLE-US-00009 TABLE IX Reaction conditions for SCR of NOx. Total gas flow (mL/min) 300 Catalyst load (mg) 40 NO concentration (ppm) 500 NH3 concentration (ppm) 530 O2 concentration (%) 7 H2O concentration (%) 5 Testing temperature interval ( C.) 170-550

(18) The catalytic results are summarized in Table X

(19) TABLE-US-00010 TABLE X NOx conversion (%) at various temperatures (200, 250, 300, 350, 400, 450, 500 C.) using different Cu-SAPO-34 materials synthesized following the methodology presented in this invention. NOx conversion (%) at different temperatures 200 C. 250 C. 300 C. 350 C. 400 C. 450 C. 500 C. Exam- 32 41 47 50 52 55 40 ple 5 Exam- 31 58 75 82 82 75 70 ple 25 Exam- 22 48 53 70 71 67 61 ple 30 Exam- 65 91 95 97 90 80 68 ple 52 Exam- 65 89 92 95 94 89 77 ple 53 Exam- 88 100 100 100 100 98 87 ple 54 Exam- 28 52 58 65 72 68 30 ple 60