US 12,263,471 B2
Rapid synthesis of a catalyst comprising a zeolite having an AFX structure and at least one transition metal for selective NOx reduction
Bogdan Harbuzaru, Rueil-Malmaison (FR); and David Berthout, Rueil-Malmaison (FR)
Assigned to IFP Energies nouvelles, Rueil-Malmaison (FR)
Appl. No. 17/604,273
Filed by IFP Energies nouvelles, Rueil-Malmaison (FR)
PCT Filed Apr. 14, 2020, PCT No. PCT/EP2020/060474
§ 371(c)(1), (2) Date Oct. 15, 2021,
PCT Pub. No. WO2020/212354, PCT Pub. Date Oct. 22, 2020.
Claims priority of application No. 1904198 (FR), filed on Apr. 19, 2019.
Prior Publication US 2022/0193645 A1, Jun. 23, 2022
Int. Cl. B01J 35/36 (2024.01); B01J 29/76 (2006.01); B01J 35/56 (2024.01); B01J 37/00 (2006.01); B01J 37/02 (2006.01); B01J 37/04 (2006.01); B01J 37/08 (2006.01); F01N 3/20 (2006.01)
CPC B01J 29/76 (2013.01) [B01J 35/56 (2024.01); B01J 37/0009 (2013.01); B01J 37/0215 (2013.01); B01J 37/04 (2013.01); B01J 37/08 (2013.01); F01N 3/2066 (2013.01); F01N 2570/14 (2013.01)] 16 Claims
 
1. A process for preparing a catalyst based on a zeolite of AFX structural type and on at least one transition metal, comprising at least the following steps:
i) the mixing, in an aqueous medium, of at least one source of at least one silicon oxide SiO2, of at least one source of at least one aluminium oxide Al2O3, of an organic nitrogen-comprising compound R, also referred to as specific structuring agent, 1,6-bis(methylpiperidinium)hexane dihydroxide, of at least one alkali metal and/or one alkaline-earth metal M with a valency n, n being an integer greater than or equal to 1, the reaction mixture having the following molar composition:
SiO2/Al2O3 between 2 and 100,
H2O/SiO2 between 5 and 60,
R/SiO2 between 0.05 and 0.50,
M2/nO/SiO2 between 0.05 and 0.40,
wherein M is one or more alkali and/or alkaline-earth metal(s) chosen from lithium, sodium, potassium, calcium, magnesium and a mixture of at least two of these metals, step i) being performed for a time enabling a homogeneous mixture known as a precursor gel to be obtained;
ii) the hydrothermal treatment of the precursor gel obtained at the end of step i) under autogenous pressure at a temperature of between 120° C. and 250° C., for a time of between 2 and 12 hours, until the zeolite of AFX structural type is formed,
iii) at least one ion exchange comprising bringing the solid obtained at the end of the previous step into contact with a solution comprising at least one species capable of releasing a transition metal in solution in reactive form, with stirring at ambient temperature for a time of between 1 hour and 2 days;
iv) a heat treatment comprising drying of the solid obtained at the end of the previous step at a temperature of between 20 and 150° C. for a time of between 2 and 24 hours, followed by at least one calcination under—optionally dry—air at a temperature of between 450 and 700° C., for a time of between 2 and 20 hours.