Synthesis of zeolite with the CHA crystal structure, synthesis process and use thereof for catalytic applications
The present invention relates to a new synthesis process of a crystalline material with the CHA structure, which comprises the following steps: i) Preparation of a mixture that comprises one source of water, one source of a tetravalent element Y, one source of an alkaline or alkaline earth cation (A), one source of a trivalent element X, and one organic molecule (OSDA1) with the structure [R 1 R 2 R 3 R 4 N + ]Q − , being the molar composition: n X 2 O 3 :YO 2 :a A:m OSDA1:z H 2 O, ii) crystallization of the mixture obtained in i) in a reactor, iii) recovery of the crystalline material obtained in ii).
1. A process of synthesizing a crystalline material with the CHA zeolite structure comprising, at least, the following steps:
i) Preparation of a mixture that comprises at least one source of water, at least one source of a tetravalent element Y, at least one source of an alkaline or alkaline earth cation A, at least one source of a trivalent element X, and at least one organic molecule (OSDA1) with the structure [R 1 R 2 R 3 R 4 N + ]Q − ,
wherein R 1 , R 2 , R 3 and R 4 are selected from linear alkyl groups, and wherein R 1 , R 2 , R 3 and R 4 each have between 1 and 4 carbon atoms, but at least two of them must have at least two carbon atoms, and wherein Q − is an anion, being the molar composition:
n X 2 O 3 :YO 2 :a A: m OSDA1: z H 2 O
wherein
n ranges between 0 and 0.1;
a ranges between 0 and 2;
m ranges between 0.01 and 2;
z ranges between 1 and 200;
ii) Crystallization of the mixture obtained in i) in a reactor
iii) Recovery of the crystalline material obtained in ii).
2. The process according to claim 1 , wherein the source of the tetravalent element Y is selected from silicon, tin, titanium, germanium, and combinations thereof.
3. The process according to claim 2 , wherein the source of the tetravalent element Y is a source of silicon selected from silicon oxide, silicon halide, colloidal silica, fumed silica, tetraalkyl orthosilicate, silicate, silicic acid, a previously synthesised crystalline material, a previously synthesised amorphous material, and combinations thereof.
4. The process according to claim 3 , wherein the source of silicon is selected from a previously synthesised crystalline material, a previously synthesised amorphous material and combinations thereof.
5. The process according to claim 4 , wherein the previously synthesised materials contain other heteroatoms in their structure.
6. The process according to claim 1 , wherein the source of the trivalent element X is selected from aluminium, boron, iron, indium, gallium, and combinations thereof.
7. The process according to claim 6 , wherein the source of the trivalent element X is aluminium.
8. The process according to claim 1 , wherein the OSDA1 is selected from tetraethylammonium, methyl triethylammonium, propyl triethylammonium, diethyl dipropylammonium, diethyl dimethylammonium, and combinations thereof.
9. The process according to claim 8 , wherein said OSDA1 is tetraethylammonium.
10. The process according to claim 1 , wherein the crystallization process described in ii) is performed in autoclaves, under static or dynamic conditions.
11. The process according to claim 1 , wherein the crystallization process described in ii) is performed at a temperature ranging between 100° C. and 200° C.
12. The process according to claim 1 , wherein the crystallization time of the process described in ii) ranges between 6 hours and 50 days.
13. The process according to claim 1 , further comprising the addition of CHA crystals to the synthesis mixture, as seeds, in a quantity of up to 25% by weight with respect to the total quantity of oxides.
14. The process according to claim 13 , wherein the CHA crystals are added before the crystallization process or during the crystallization process.
15. The process according to claim 1 , wherein recovery step iii) is performed by means of a separation technique selected from decantation, filtration, ultrafiltration, centrifugation, and combinations thereof.
16. The process according to claim 1 , wherein it further comprises the elimination of the organic content retained inside the material by means of an extraction process.
17. The process according to claim 1 , wherein it further comprises the elimination of the organic content retained inside the material by means of a heat treatment at temperatures ranging between 100° C. and 1000° C. for a period of time ranging between 2 minutes and 25 hours.
18. The process according to claim 1 , wherein the material obtained is pelletized.
19. The process according to claim 1 , wherein any cation present in the material may be exchanged with other cations by means of ion exchange.
20. The process according to claim 19 , wherein the exchanged cation is selected from metals, protons, proton precursors, and mixtures thereof.
21. The process according to claim 20 , wherein the exchanged cation is a metal selected from rare earths, metals of groups IIA, IIIA, IVA, VA, IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIII, and combinations thereof.
22. The process according to claim 21 , wherein the metal is copper.
23. A zeolite material with the CHA structure obtained according to the process described in claim 1 , wherein it has the following molar composition:
o X 2 O 3 :YO 2 :p A: q OSDA1: r H 2 O
wherein
X is a trivalent element;
Y is a tetravalent element;
A is an alkaline or alkaline earth cation;
o ranges between 0 and 0.1;
p ranges between 0 and 1;
q ranges between 0.01 and 1; and
r ranges between 0 and 2.
24. The zeolite material with the CHA structure according to claim 23 , having the following molar composition after being calcined:
n X 2 O 3 :YO 2
where
X is a trivalent element;
Y is a tetravalent element; and
n ranges between 0 and 0.1.
25. The zeolite material with the CHA structure according to claim 23 , wherein the tetravalent element Y is selected from silicon, tin, titanium, germanium, and combinations thereof.
26. The zeolite material with the CHA structure according to claim 23 , wherein the trivalent element X is selected from aluminium, boron, iron, indium, gallium, and combinations thereof.
27. A method for converting, eliminating, or separating feeds formed by organic compounds in a high-added-value product, which comprises bringing said feed into contact with a zeolite material with the CHA structure made according to the process of claim 1 .
28. A method of producing an olefin, which comprises contacting an oxygenated organic compound with a zeolite material with the CHA structure made according to the process of claim 1 .
29. A method of selective catalytic reduction (SCR) of NOx (nitrogen oxides) in a gas stream, which comprises contacting the gas stream with a zeolite material with the CHA structure made according to the process of claim 1 .