WO2024017884A1

WO2024017884A1 - Process for the catalytic activation of n2o

Info

Publication number: WO2024017884A1
Application number: PCT/EP2023/069905
Authority: WO
Inventors: Trees Maria DE BAERDEMAEKER; Andrei-Nicolae PARVULESCU; Toshiyuki Yokoi
Original assignee: Basf Se
Priority date: 2022-07-19
Filing date: 2023-07-18
Publication date: 2024-01-25

Abstract

The present invention relates to a process for the activation of N₂O comprising (i) providing a gas stream comprising N₂O; (ii) contacting the gas stream provided in (i) with a catalyst at a temperature in the range of from 300 to 600 °C, wherein the catalyst comprises a zeolitic material having the AEI-type framework structure, wherein the framework structure of the zeolitic material comprises SiO₂ and Al₂O₃, and wherein the zeolitic material contains copper.

Description

Process for the catalytic activation of N₂O TECHNICAL FIELD The present invention relates to a process for the activation of N₂O comprising contacting a gas stream containing N₂O with a catalyst comprising a zeolitic material having the AEI-type frame- work structure, wherein the zeolitic material contains copper. INTRODUCTION Zeolitic materials having framework type AEI are known to be potentially effective as catalysts or catalyst components for treating combustion exhaust gas in industrial applications, for exam- ple for converting nitrogen oxides (NOx) in an exhaust gas stream. Synthetic AEI zeolitic materi- als are generally produced by precipitating crystals of the zeolitic material from a synthesis mix- ture which contains the sources of the elements from which the zeolitic framework is built, such as a source of silicon and a source of aluminum. An alternative approach may be the prepara- tion via zeolitic framework conversion according to which a starting material which is a suitable zeolitic material having a framework type other than AEI is suitably reacted to obtain the zeolitic material having framework type AEI. Thus, US 5,958,370 relates to SSZ-39 and to its preparation using cyclic or polycyclic quater- nary ammonium cations as templating agent. Moliner, M. et al. in Chem. Commun.2012, 48, pages 8264-8266, on the other hand, concerns Cu-SSZ-39 and its use for the SCR of nitrogen oxides NOx, wherein the SSZ-39 is produced with the use of N,N-dimethyl-3,5-dimethylpiperi- dinium cations as the organotemplate. Maruo, T. et al. in Chem. Lett.2014, 43, page 302-304 relates to the synthesis of AEI zeolites by hydrothermal conversion of FAU zeolites in the pres- ence of tetraethylphosphonium cations. Martín, N. et al. in Chem. Commun.2015, 51, 11030- 11033 concerns the synthesis of Cu-SSZ-39 and its use as a catalyst in the SCR of nitrogen ox- ides NOx. As regards the methods of synthesis of the SSZ-39 zeolite in said document, these include the use of N,N-dimethyl-3,5-dimethylpiperidinium cations as well as of tetrae- thylphosphonium cations. Dusselier, M. et al. in ACS Catal.2015, 5, 10, 6078-6085, on the other hand, describe methanol to olefin catalysis using hydrothermally treated SSZ-39. US 2015/0118150 A1 describes zeolite synthesis methods involving the use of N,N-dimethyl- 3,5-dimethylpiperidinium and N,N-dimethyl-2,6-dimethylpiperidinium cations, respectively. WO 2016/149234 A1 and Ransom, R. et al. in Ind. Eng. Chem. Res.2017, 56, 4350−4356 respec- tively relate to the synthesis of SSZ-39 via interzeolitic conversion of faujasite using N,N-dime- thyl-3,5-dimethylpiperidinium cations as the organotemplate. WO 2018/113566 A1, on the other hand, relates to the synthesis of zeolites via solvent-free interzeolitic conversion, wherein the synthesis of SSZ-39 from interzeolitic conversion of zeolite Y using N,N-dimethyl-2,6-dimethylpi- peridinium cations is described. WO 2016/149234 A1 and Ransom, R. et al. in Ind. Eng. Chem. Res.2017, 56, 4350-4356 re- spectively relate to the synthesis of SSZ-39 using different isomer ratios of the cis and trans iso- mers of the N,N-dimethyl-3,5-dimethylpiperidinium cation. WO 2020/098796 A1, on the other hand, concerns the production of an AEI-type zeolitic material via solvent-free interzeolitic con- version, wherein N,N-dimethyl-3,5-dimethylpiperidinium having a specific ratio of cis and trans isomers was employed. WO 2018/234044 A1 relates to a process for the oxidation of lower alkanes in the presence of ammonia over a copper loaded zeolite catalyst. Memioglu, O. et al., “A potential catalyst for continuous methane partial oxidation to methanol using N₂O : Cu-SSZ-39”, Chem. Comm. 2021, 57, 1364-1367, on the other hand, describes the use of Cu-SSZ-39 as a catalyst for con- tinuous methane partial oxidation to methanol, wherein conversions are performed at 573 and 598 K (300 and 325 °C), respectively. WO 2017/134007 A1 concerns a method for the removal of nitrous oxide from an off gas over an iron loaded zeolite having the AEI-type framework structure. US 2016/264428 A1 discloses the production of zeolites by selective use of the trans isomer of 3,5-dimethyl-N,N-dimethylpiperidinium hydroxide, or of a mixture of cis and trans isomers with an enhanced content of the trans isomer. Despite the current applications involving the use of zeolitic material of the AEI-type framework structure, there remains the need for new applications which may further exploit the unique physical and chemical characteristics of this highly specific framework structure type among ze- olitic materials, in particular as a catalyst when used in conjunction with catalytically active tran- sition metals. DETAILED DESCRIPTION It was therefore the object of the present invention to provide novel applications for zeolitic ma- terials of the AEI-type framework structure when employed in conjunction with copper. Thus, it has surprisingly been found that at elevated temperatures, zeolitic materials of the AEI-type framework structure loaded with copper are able to activate N₂O to the effect that it may react with reducing agents such as hydrocarbons to a substantial extent. In particular, it has unex- pectedly been found that activation of N₂O with zeolitic materials of the AEI-type framework structure loaded with copper may even allow for near total to total conversion thereof in the presence of hydrocarbons such as methane as a reducing agent. Accordingly, it has surpris- ingly been found that AEI-type zeolitic materials loaded with copper may allow for the controlled conversion of N₂O at elevated temperatures in chemical conversions such as the oxidation of hydrocarbons. Furthermore, it has unexpectedly been found that the use of specific isomer ra- tios among the chiral structure directing agents used in the synthesis of the AEI-type framework structure leads to striking differences in the rate of N₂O activation, in particular in the intermedi- ate temperature ranges. The present invention therefore relates to a process for the activation of N₂O comprising (i) providing a gas stream comprising N₂O; (ii) contacting the gas stream provided in (i) with a catalyst at a temperature in the range of from 300 to 600 °C, wherein the catalyst comprises a zeolitic material having the AEI-type framework structure, wherein the framework structure of the zeolitic material comprises SiO₂ and Al₂O₃, and wherein the zeolitic material contains copper. It is preferred that the gas stream in (i) contains N₂O in an amount ranging from 1 to 100 vol.-%, more preferably from 5 to 90 vol.-%, more preferably from 10 to 80 vol.-%, more preferably from 15 to 70 vol.-%, more preferably from 20 to 60 vol.-%, more preferably from 25 to 55 vol.-%, more preferably from 30 to 50 vol.-%, more preferably from 35 to 45 vol.-%, and more prefera- bly from 38 to 42 vol.-%. It is preferred that the gas stream in (i) further comprises a reducing agent. It is preferred that the reducing agent is selected from the group consisting of hydrocarbons, more preferably from the group consisting of (C₁-C₈)alkanes, more preferably from the group consisting of (C₁-C₇)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₆)alkanes, including mixtures of two or more thereof, more prefera- bly from the group consisting of (C₁-C₅)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₄)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₃)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₂)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of methane and ethane, in- cluding mixtures thereof, wherein more preferably the reducing agent comprises methane, wherein more preferably the reducing agent is methane. It is preferred that contacting in (ii) of the gas stream provided in (i) with a catalyst is conducted at a temperature in the range of from 350 to 550 °C, more preferably of from 400 to 550 °C, and more preferably of from 450 to 500 °C. It is preferred that the SiO₂ : Al₂O₃ molar ratio of the zeolitic material having the AEI-type frame- work structure is in the range of from 4 to 200, more preferably of from 6 to 120, more prefera- bly of from 8 to 80, more preferably of from 10 to 50, more preferably of from 12 to 35, more preferably of from 14 to 30, more preferably of from 16 to 25, more preferably of from 18 to 22, and more preferably of from 19.5 to 20.5. It is preferred that the zeolitic material having the AEI-type framework structure is ion ex- changed with copper. It is preferred that the zeolitic material having the AEI-type framework structure contains copper in an amount in the range of from 0.1 to 12 wt.-% based on 100 wt.-% of the zeolitic material having the AEI-type framework structure, wherein copper is calculated as the element, wherein more preferably the zeolitic material having the AEI-type framework structure contains copper in an amount in the range of from 0.3 to 10 wt.-%, more preferably of from 0.5 to 8 wt.-%, more preferably of from 0.7 to 6 wt.-%, more preferably of from 0.9 to 4 wt.-%, more preferably of from 1.1 to 3 wt.-%, more preferably of from 1.3 to 2.5 wt.-%, more preferably of from 1.5 to 2.3 wt.- %, more preferably of from 1.7 to 2 wt.-%, and more preferably of from 1.8 to 1.9 wt.-% based on 100 wt.-% of the zeolitic material having the AEI-type framework structure. It is preferred that the zeolitic material having the AEI-type framework structure comprised in the catalyst is prepared by a process comprising (1) preparing a mixture comprising one or more sources of SiO₂, a first zeolitic material com- prising SiO₂ and Al₂O₃ in its framework structure and having an FAU-type framework structure, one or more cationic structure directing agents, and water; (2) heating the mixture obtained in (1) for obtaining a second zeolitic material comprising SiO₂ and Al₂O₃ in its framework structure and having an AEI-type framework structure. In the case where the zeolitic material having the AEI-type framework structure comprised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the one or more cationic structure directing agents are selected from the group consisting of N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpyrrolidinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpiperi- dinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylhexahydroazepinium, and mixtures of two or more thereof, more preferably from the group consisting of N,N-di(C₁-C₃)alkyl-3,5-di(C₁-C₃)alkylpyrrolidinium, N,N-di(C₁-C₃)alkyl-3,5-di(C₁-C₃)alkylpiperidinium, N,N-di(C₁-C₃)alkyl-3,5-di(C₁-C₃)alkylhexahy- droazepinium, and mixtures of two or more thereof, more preferably from the group consisting of N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylpyrrolidinium , N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylpiperidinium, N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylhexahy- droazepinium, and mixtures of two or more thereof, more preferably from the group consisting of N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylpiperidinium, and mixtures of two or more thereof, wherein more preferably the one or more cationic structure directing agents comprises N,N-dimethyl-3,5-dimethylpiperidinium, wherein more preferably the one or more cationic structure directing agents consists of N,N-dimethyl-3,5-dimethylpiperi- dinium. In the case where the one or more cationic structure directing agents are selected from the group consisting of N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpyrrolidinium, N,N-di(C₁-C₄)alkyl-3,5- di(C₁-C₄)alkylpiperidinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylhexahydroazepinium, and mix- tures of two or more thereof, it is preferred according to a first alternative that the cis : trans mo- lar ratio of the cis isomer to the trans isomer in the one or more cationic structure directing agents relative to the alkyl groups at the 3 and 5 positions of the heterocyclic amine ring is in the range of from 0.01:1 to 0.95:1, more preferably of from 0.03:1 to 0.9:1, more preferably of from 0.05:1 to 0.7:1, more preferably of from 0.07:1 to 0.5:1, more preferably of from 0.1:1 to 0.45:1, more preferably of from 0.13:1 to 0.4:1, more preferably of from 0.15:1 to 0.35:1, more preferably of from 0.18:1 to 0.33:1, more preferably of from 0.2:1 to 0.3:1, and more preferably of from 0.23:1 to 0.27:1. In the case where the one or more cationic structure directing agents are selected from the group consisting of N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpyrrolidinium, N,N-di(C₁-C₄)alkyl-3,5- di(C₁-C₄)alkylpiperidinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylhexahydroazepinium, and mix- tures of two or more thereof, it is preferred according to a second alternative that the trans : cis molar ratio of the trans isomer to the cis isomer in the one or more cationic structure directing agents relative to the alkyl groups at the 3 and 5 positions of the heterocyclic amine ring is in the range of from 1:1 to 0:1, more preferably of from 0.8:1 to 0:1, more preferably of from 0.5:1 to 0:1, more preferably of from 0.4:1 to 0:1, more preferably of from 0.3:1 to 0:1, more prefera- bly of from 0.2:1 to 0:1, more preferably of from 0.1:1 to 0:1, more preferably of from 0.05:1 to 0:1, and more preferably of from 0.01:1 to 0:1. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the one or more cationic structure directing agents are provided as salts, pref- erably as one or more salts selected from the group consisting of halides, sulfate, nitrate, phos- phate, acetate, and mixtures of two or more thereof, more preferably from the group consisting of bromide, chloride, hydroxide, sulfate, and mixtures of two or more thereof, wherein more pref- erably the one or more cationic structure directing agents are provided as hydroxides and/or bromides, and more preferably as hydroxides. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the framework structure of the first zeolitic material displays a SiO₂ : Al₂O₃ mo- lar ratio ranging from 1.5 to 100, more preferably of from 2 to 50, more preferably of from 2.5 to 25, more preferably of from 3 to 15, more preferably of from 3.5 to 10, more preferably of from 4 to 7, and more preferably of from 4.5 to 5. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the mixture prepared in (1) and heated in (2) displays an SDA : Si molar ratio of the one or more cationic structure directing agents (SDA) to Si contained in the mixture in the range of from 0.01 to 1.5, more preferably of from 0.05 to 1.2, more preferably of from 0.1 to 0.8, more preferably of from 0.3 to 0.6, more preferably of from 0.5 to 0.45, more preferably of from 0.8 to 0.35, more preferably of from 0.1 to 0.3, more preferably of from 0.13 to 0.25, and more preferably of from 0.15 to 0.2. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the one or more sources of SiO₂ is selected from the group consisting of fumed silica, silica hydrosols, reactive amorphous solid silicas, silica gel, silicic acid, water glass, so- dium metasilicate hydrate, sesquisilicate, disilicate, colloidal silica, silicic acid esters, and mix- tures of two or more thereof, more preferably from the group consisting of fumed silica, silica hy- drosols, reactive amorphous solid silicas, silica gel, silicic acid, colloidal silica, silicic acid esters, and mixtures of two or more thereof, more preferably from the group consisting of fumed silica, silica hydrosols, reactive amorphous solid silicas, silica gel, colloidal silica, and mixtures of two or more thereof, wherein even more preferably the one or more sources for YO₂ comprises fumed silica and/or colloidal silica, preferably fumed silica. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the first zeolitic material having an FAU-type framework structure is selected from the group consisting of ZSM-3, Faujasite, [Al-Ge-O]-FAU, CSZ-1, ECR-30, Zeolite X, Zeo- lite Y, LZ-210, SAPO-37, ZSM-20, Na-X, US-Y, Na-Y, [Ga-Ge-O]-FAU, Li-LSX, [Ga-Al-Si-O]- FAU, and [Ga-Si-O]-FAU, including mixtures of two or more thereof, more preferably from the group consisting of ZSM-3, Faujasite, CSZ-1, ECR-30, Zeolite X, Zeo- lite Y, LZ-210, ZSM-20, Na-X, US-Y, Na-Y, and Li-LSX, including mixtures of two or more thereof, more preferably from the group consisting of Faujasite, Zeolite X, Zeolite Y, Na-X, US-Y, and Na-Y, including mixtures of two or more thereof, more preferably from the group consisting of Faujasite, Zeolite X, and Zeolite Y, including mix- tures of two or more thereof, wherein more preferably the first zeolitic material having an FAU-type framework structure com- prises zeolite X and/or zeolite Y, preferably zeolite Y, wherein more preferably the first zeolitic material having an FAU-type framework structure is ze- olite X and/or zeolite Y, preferably zeolite Y. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the mixture prepared in (1) further comprises OH-. In the case where the mixture prepared in (1) further comprises OH-, it is preferred that the OH- : Si molar ratio of hydroxide to Si contained in the mixture prepared in (1) is in the range of from 0.01 to 5, more preferably from 0.05 to 3, more preferably from 0.1 to 1.5, more preferably from 0.2 to 1, more preferably from 0.3 to 0.8, and more preferably from 0.5 to 0.7, and more prefera- bly from 0.6 to 0.65. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the mixture prepared in (1) further comprises one or more alkali metals M, more preferably one or more alkali metals M selected from the group consisting of Na, K, and mix- tures thereof, wherein more preferably the mixture prepared in (1) further comprises Na as the alkali metal M. In the case where the mixture prepared in (1) further comprises one or more alkali metals M, it is preferred that the M : Si atomic ratio of the one or more alkali metals M to Si contained in the mixture prepared in (1) is in the range of from 0.01 to 2.5, more preferably of from 0.05 to 1.5, more preferably of from 0.1 to 1.0, more preferably of from 0.3 to 0.7, more preferably of from 0.4 to 0.5, and more preferably of from 0.45 to 0.47. Further in the case where the mixture prepared in (1) further comprises one or more alkali met- als M, it is preferred that the one or more alkali metals M are comprised in the mixture prepared in (1) as hydroxide. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the mixture prepared in (1) contains water at an H₂O : Si molar ratio in the range of from 1 to 60, more preferably of from 5 to 40, more preferably of from 10 to 30, more preferably of from 15 to 25, and more preferably of from 18 to 22. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that heating in (2) is conducted at a temperature in the range of from 80 to 250 °C, more preferably from 100 to 230 °C, more preferably from 110 to 220 °C, more preferably from 115 to 210 °C, more preferably from 120 to 200 °C, more preferably from 125 to 190 °C, more preferably from 130 to 180 °C, more preferably from 135 to 170 °C, more preferably from 140 to 160 °C, and more preferably from 145 to 155 °C. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that heating in (2) is conducted under autogenous pressure, more preferably under hydrothermal conditions. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the heating in (2) is performed in a pressure tight vessel, more preferably in an autoclave. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that heating in (2) is conducted for a duration in the range of from 3 h to 10 d, more preferably from 6 h to 8 d, more preferably from 12 h to 6 d, more preferably from 1 to 5 d, more preferably from 1.5 to 4.5 d, more preferably from 2 to 4 d, and more preferably from 2.5 to 3.5 d. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the second zeolitic material obtained in (2) having an AEI-type framework struc- ture is selected from the group consisting of SSZ-39, SAPO-18, SIZ-8, including mixtures of two or more thereof, wherein more preferably the second zeolitic material obtained in (2) comprises SSZ-39, and wherein more preferably the second zeolitic material obtained in (2) is SSZ-39. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the process further comprises (3) calcining the second zeolitic material obtained in (2). Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the process further comprises (4) subjecting the zeolitic material obtained in (2) or (3) to an ion-exchange procedure, wherein one or more ionic extra-framework elements contained in the zeolite framework is ion- exchanged against H⁺ and/or NH₄ ⁺, more preferably against NH₄ ⁺. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the process further comprises (5) subjecting the zeolitic material obtained in (2), (3), or (4) to an ion-exchange procedure, wherein one or more ionic extra-framework elements contained in the zeolite framework is ion- exchanged against copper. In the case where the process further comprises (5) as defined hereinabove, it is preferred that the process further comprises (6) calcining the zeolitic material obtained in (5). In the case where the process further comprises (3) and/or (6) as defined herein above, it is preferred that the temperature of calcination in (3) and/or (6) is in the range of from 300 to 900 °C, more preferably of from 400 to 700 °C, more preferably of from 450 to 650 °C, and more preferably of from 500 to 600 °C. Further in the case where the process further comprises (3) and/or (6) as defined herein above, it is preferred that calcining in (3) and/or (6) is conducted for a period in the range of from 0.5 to 10 h, more preferably from 1 to 15 h, more preferably from 2 to 12 h, more preferably from 3 to 9 h, more preferably from 4 to 7 h, more preferably from 4.5 to 6.5 h, and more preferably from 5 to 6 h. Further in the case where the zeolitic material having the AEI-type framework structure com- prised in the catalyst is prepared by a process comprising (1) and (2) as defined hereinabove, it is preferred that the mixture in (1) further comprises seed crystals, wherein the seed crystals more preferably comprise a zeolitic material having an AEI-type framework structure, wherein more preferably the zeolitic material consists of a zeolitic material having an AEI-type framework structure. In the case where the mixture in (1) further comprises seed crystals, it is preferred that the zeo- litic material having an AEI-type framework structure comprised in the seed crystals is selected from the group consisting of SSZ-39, SAPO-18, SIZ-8, including mixtures of two or more thereof, wherein more preferably the zeolitic material having an AEI-type framework structure comprised in the seed crystals is SSZ-39. Further in the case where the mixture in (1) further comprises seed crystals, it is preferred that the amount of seed crystals in the mixture prepared in (1) and heated in (2) ranges from 3 to 12 wt.-% based on 100 wt.-% of Si in the mixture prepared in (1) calculated as the element, more preferably from 3.5 to 10 wt.-%, more preferably from 4 to 9 wt.-%, more preferably from 4.5 to 7 wt.-%, and more preferably from 5 to 6 wt.-% based on 100 wt.-% of Si in the mixture prepared in (1) calculated as the element. The present invention is further illustrated by the following set of embodiments and combina- tions of embodiments resulting from the dependencies and back-references as indicated. In par- ticular, it is noted that in each instance where a range of embodiments is mentioned, for exam- ple in the context of a term such as "The composite oxide of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The composite oxide of any one of embodiments 1, 2, 3, and 4". Further, it is explicitly noted that the following set of embodiments is not the set of claims determining the extent of protection, but represents a suitably structured part of the description directed to general and preferred aspects of the present invention. 1. A process for the activation of N₂O comprising (i) providing a gas stream comprising N₂O; (ii) contacting the gas stream provided in (i) with a catalyst at a temperature in the range of from 300 to 600 °C, wherein the catalyst comprises a zeolitic material having the AEI-type framework structure, wherein the framework structure of the zeolitic material comprises SiO₂ and Al₂O₃, and wherein the zeolitic material contains copper. 2. The process of embodiment 1, wherein the gas stream in (i) contains N₂O in an amount ranging from 1 to 100 vol.-%, preferably from 5 to 90 vol.-%, more preferably from 10 to 80 vol.-%, more preferably from 15 to 70 vol.-%, more preferably from 20 to 60 vol.-%, more preferably from 25 to 55 vol.-%, more preferably from 30 to 50 vol.-%, more prefera- bly from 35 to 45 vol.-%, and more preferably from 38 to 42 vol.-%. 3. The process of embodiment 1 or 2, wherein the gas stream in (i) further comprises a re- ducing agent. 4. The process of any of embodiments 1 to 3, wherein the reducing agent is selected from the group consisting of hydrocarbons, preferably from the group consisting of (C₁-C₈)al- kanes, more preferably from the group consisting of (C₁-C₇)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₆)alkanes, includ- ing mixtures of two or more thereof, more preferably from the group consisting of (C₁- C₅)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₄)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₃)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of (C₁-C₂)alkanes, including mixtures of two or more thereof, more preferably from the group consisting of methane and ethane, including mixtures thereof, wherein more preferably the reducing agent comprises methane, wherein more preferably the reducing agent is methane. 5. The process of any of embodiments 1 to 4, wherein contacting in (ii) of the gas stream provided in (i) with a catalyst is conducted at a temperature in the range of from 350 to 550 °C, preferably of from 400 to 550 °C, and more preferably of from 450 to 500 °C. 6. The process of any of embodiments 1 to 5, wherein the SiO₂ : Al₂O₃ molar ratio of the zeo- litic material having the AEI-type framework structure is in the range of from 4 to 200, pref- erably of from 6 to 120, more preferably of from 8 to 80, more preferably of from 10 to 50, more preferably of from 12 to 35, more preferably of from 14 to 30, more preferably of from 16 to 25, more preferably of from 18 to 22, and more preferably of from 19.5 to 20.5. 7. The process of any of embodiments 1 to 6, wherein the zeolitic material having the AEI- type framework structure is ion exchanged with copper. 8. The process of any of embodiments 1 to 7, wherein the zeolitic material having the AEI- type framework structure contains copper in an amount in the range of from 0.1 to 12 wt.- % based on 100 wt.-% of the zeolitic material having the AEI-type framework structure, wherein copper is calculated as the element, wherein preferably the zeolitic material hav- ing the AEI-type framework structure contains copper in an amount in the range of from 0.3 to 10 wt.-%, more preferably of from 0.5 to 8 wt.-%, more preferably of from 0.7 to 6 wt.-%, more preferably of from 0.9 to 4 wt.-%, more preferably of from 1.1 to 3 wt.-%, more preferably of from 1.3 to 2.5 wt.-%, more preferably of from 1.5 to 2.3 wt.-%, more preferably of from 1.7 to 2 wt.-%, and more preferably of from 1.8 to 1.9 wt.-% based on 100 wt.-% of the zeolitic material having the AEI-type framework structure. 9. The process of any of embodiments 1 to 8, wherein the zeolitic material having the AEI- type framework structure comprised in the catalyst is prepared by a process comprising (1) preparing a mixture comprising one or more sources of SiO₂, a first zeolitic material comprising SiO₂ and Al₂O₃ in its framework structure and having an FAU-type framework structure, one or more cationic structure directing agents, and water; (2) heating the mixture obtained in (1) for obtaining a second zeolitic material compris- ing SiO₂ and Al₂O₃ in its framework structure and having an AEI-type framework structure. 10. The process of embodiment 9, wherein the one or more cationic structure directing agents are selected from the group consisting of N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpyrroli- dinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpiperidinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁- C₄)alkylhexahydroazepinium, and mixtures of two or more thereof, preferably from the group consisting of N,N-di(C₁-C₃)alkyl-3,5-di(C₁-C₃)alkylpyrrolidinium, N,N-di(C₁-C₃)alkyl-3,5-di(C₁-C₃)alkylpiperidinium, N,N-di(C₁-C₃)alkyl-3,5-di(C₁-C₃)alkylhex- ahydroazepinium, and mixtures of two or more thereof, more preferably from the group consisting of N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylpyrroli- dinium, N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylpiperidinium, N,N-di(C₁-C₂)alkyl-3,5-di(C₁- C₂)alkylhexahydroazepinium, and mixtures of two or more thereof, more preferably from the group consisting of N,N-di(C₁-C₂)alkyl-3,5-di(C₁-C₂)alkylpiperi- dinium, and mixtures of two or more thereof, wherein more preferably the one or more cat- ionic structure directing agents comprises N,N-dimethyl-3,5-dimethylpiperidinium, wherein more preferably the one or more cationic structure directing agents consists of N,N-dime- thyl-3,5-dimethylpiperidinium. 11. The process of embodiment 10, wherein the cis : trans molar ratio of the cis isomer to the trans isomer in the one or more cationic structure directing agents relative to the alkyl groups at the 3 and 5 positions of the heterocyclic amine ring is in the range of from 0.01:1 to 0.95:1, preferably of from 0.03:1 to 0.9:1, more preferably of from 0.05:1 to 0.7:1, more preferably of from 0.07:1 to 0.5:1, more preferably of from 0.1:1 to 0.45:1, more pref- erably of from 0.13:1 to 0.4:1, more preferably of from 0.15:1 to 0.35:1, more preferably of from 0.18:1 to 0.33:1, more preferably of from 0.2:1 to 0.3:1, and more preferably of from 0.23:1 to 0.27:1. 12. The process of embodiment 10, wherein the trans : cis molar ratio of the trans isomer to the cis isomer in the one or more cationic structure directing agents relative to the alkyl groups at the 3 and 5 positions of the heterocyclic amine ring is in the range of from 1:1 to 0:1, preferably of from 0.8:1 to 0:1, more preferably of from 0.5:1 to 0:1, more preferably of from 0.4:1 to 0:1, more preferably of from 0.3:1 to 0:1, more preferably of from 0.2:1 to 0:1, more preferably of from 0.1:1 to 0:1, more preferably of from 0.05:1 to 0:1, and more preferably of from 0.01:1 to 0:1. 13. The process of any of embodiments 9 to 12, wherein the one or more cationic structure directing agents are provided as salts, preferably as one or more salts selected from the group consisting of halides, sulfate, nitrate, phosphate, acetate, and mixtures of two or more thereof, more preferably from the group consisting of bromide, chloride, hydroxide, sulfate, and mixtures of two or more thereof, wherein more preferably the one or more cat- ionic structure directing agents are provided as hydroxides and/or bromides, and more preferably as hydroxides. 14. The process of any of embodiments 9 to 13, wherein the framework structure of the first zeolitic material displays a SiO₂ : Al₂O₃ molar ratio ranging from 1.5 to 100, preferably of from 2 to 50, more preferably of from 2.5 to 25, more preferably of from 3 to 15, more pref- erably of from 3.5 to 10, more preferably of from 4 to 7, and more preferably of from 4.5 to 5. 15. The process of any of embodiments 9 to 14, wherein the mixture prepared in (1) and heated in (2) displays an SDA : Si molar ratio of the one or more cationic structure direct- ing agents (SDA) to Si contained in the mixture in the range of from 0.01 to 1.5, preferably of from 0.05 to 1.2, more preferably of from 0.1 to 0.8, more preferably of from 0.3 to 0.6, more preferably of from 0.5 to 0.45, more preferably of from 0.8 to 0.35, more preferably of from 0.1 to 0.3, more preferably of from 0.13 to 0.25, and more preferably of from 0.15 to 0.2. 16. The process of any of embodiments 9 to 15, wherein the one or more sources of SiO₂ is selected from the group consisting of fumed silica, silica hydrosols, reactive amorphous solid silicas, silica gel, silicic acid, water glass, sodium metasilicate hydrate, sesquisilicate, disilicate, colloidal silica, silicic acid esters, and mixtures of two or more thereof, preferably from the group consisting of fumed silica, silica hydrosols, reactive amorphous solid sili- cas, silica gel, silicic acid, colloidal silica, silicic acid esters, and mixtures of two or more thereof, more preferably from the group consisting of fumed silica, silica hydrosols, reac- tive amorphous solid silicas, silica gel, colloidal silica, and mixtures of two or more thereof, wherein even more preferably the one or more sources for YO₂ comprises fumed silica and/or colloidal silica, preferably fumed silica. 17. The process of any of embodiments 9 to 16, wherein the first zeolitic material having an FAU-type framework structure is selected from the group consisting of ZSM-3, Faujasite, [Al-Ge-O]-FAU, CSZ-1, ECR-30, Zeolite X, Zeolite Y, LZ-210, SAPO-37, ZSM-20, Na-X, US-Y, Na-Y, [Ga-Ge-O]-FAU, Li-LSX, [Ga-Al-Si-O]-FAU, and [Ga-Si-O]-FAU, including mixtures of two or more thereof, preferably from the group consisting of ZSM-3, Faujasite, CSZ-1, ECR-30, Zeolite X, Zeo- lite Y, LZ-210, ZSM-20, Na-X, US-Y, Na-Y, and Li-LSX, including mixtures of two or more thereof, more preferably from the group consisting of Faujasite, Zeolite X, Zeolite Y, Na-X, US-Y, and Na-Y, including mixtures of two or more thereof, more preferably from the group consisting of Faujasite, Zeolite X, and Zeolite Y, including mixtures of two or more thereof, wherein more preferably the first zeolitic material having an FAU-type framework structure comprises zeolite X and/or zeolite Y, preferably zeolite Y, wherein more preferably the first zeolitic material having an FAU-type framework structure is zeolite X and/or zeolite Y, preferably zeolite Y. 18. The process of any of embodiments 9 to 17, wherein the mixture prepared in (1) further comprises OH-. 19. The process of embodiment 18, wherein the OH- : Si molar ratio of hydroxide to Si con- tained in the mixture prepared in (1) is in the range of from 0.01 to 5, preferably from 0.05 to 3, more preferably from 0.1 to 1.5, more preferably from 0.2 to 1, more preferably from 0.3 to 0.8, and more preferably from 0.5 to 0.7, and more preferably from 0.6 to 0.65. 20. The process of any of embodiments 9 to 19, wherein the mixture prepared in (1) further comprises one or more alkali metals M, preferably one or more alkali metals M selected from the group consisting of Na, K, and mixtures thereof, wherein more preferably the mixture prepared in (1) further comprises Na as the alkali metal M. 21. The process of embodiment 20, wherein the M : Si atomic ratio of the one or more alkali metals M to Si contained in the mixture prepared in (1) is in the range of from 0.01 to 2.5, preferably of from 0.05 to 1.5, more preferably of from 0.1 to 1.0, more preferably of from 0.3 to 0.7, more preferably of from 0.4 to 0.5, and more preferably of from 0.45 to 0.47. 22. The process of embodiment 20 or 21, wherein the one or more alkali metals M are com- prised in the mixture prepared in (1) as hydroxide. 23. The process of any of embodiments 9 to 22, wherein the mixture prepared in (1) contains water at an H₂O : Si molar ratio in the range of from 1 to 60, preferably of from 5 to 40, more preferably of from 10 to 30, more preferably of from 15 to 25, and more preferably of from 18 to 22. 24. The process of any of embodiments 9 to 23, wherein heating in (2) is conducted at a tem- perature in the range of from 80 to 250 °C, preferably from 100 to 230 °C, more preferably from 110 to 220 °C, more preferably from 115 to 210 °C, more preferably from 120 to 200 °C, more preferably from 125 to 190 °C, more preferably from 130 to 180 °C, more prefer- ably from 135 to 170 °C, more preferably from 140 to 160 °C, and more preferably from 145 to 155 °C. 25. The process of any of embodiments 9 to 24, wherein heating in (2) is conducted under au- togenous pressure, preferably under hydrothermal conditions. 26. The process of any of embodiments 9 to 25, wherein the heating in (2) is performed in a pressure tight vessel, preferably in an autoclave. 27. The process of any of embodiments 9 to 26, wherein heating in (2) is conducted for a du- ration in the range of from 3 h to 10 d, preferably from 6 h to 8 d, more preferably from 12 h to 6 d, more preferably from 1 to 5 d, more preferably from 1.5 to 4.5 d, more preferably from 2 to 4 d, and more preferably from 2.5 to 3.5 d. 28. The process of any of embodiments 9 to 27, wherein the second zeolitic material obtained in (2) having an AEI-type framework structure is selected from the group consisting of SSZ-39, SAPO-18, SIZ-8, including mixtures of two or more thereof, wherein more prefer- ably the second zeolitic material obtained in (2) comprises SSZ-39, and wherein more preferably the second zeolitic material obtained in (2) is SSZ-39. 29. The process of any of embodiments 9 to 28, further comprising (3) calcining the second zeolitic material obtained in (2). 30. The process of any of embodiments 9 to 29, further comprising (4) subjecting the zeolitic material obtained in (2) or (3) to an ion-exchange procedure, wherein one or more ionic extra-framework elements contained in the zeolite framework is ion-exchanged against H⁺ and/or NH₄ ⁺, more preferably against NH₄ ⁺. 31. The process of any of embodiments 9 to 30, further comprising (5) subjecting the zeolitic material obtained in (2), (3), or (4) to an ion-exchange proce- dure, wherein one or more ionic extra-framework elements contained in the zeolite frame- work is ion-exchanged against copper. 32. The process of embodiment 31, further comprising (6) calcining the zeolitic material obtained in (5). 33. The process of any of embodiments 29 to 32, wherein the temperature of calcination in (3) and/or (6) is in the range of from 300 to 900°C, preferably of from 400 to 700°C, more preferably of from 450 to 650°C, and more preferably of from 500 to 600°C. 34. The process of any of embodiments 29 to 33, wherein calcining in (3) and/or (6) is con- ducted for a period in the range of from 0.5 to 10 h, preferably from 1 to 15 h, more prefer- ably from 2 to 12 h, more preferably from 3 to 9 h, more preferably from 4 to 7 h, more preferably from 4.5 to 6.5 h, and more preferably from 5 to 6 h. 35. The process of any of embodiments 9 to 34, wherein the mixture in (1) further comprises seed crystals, wherein the seed crystals preferably comprise a zeolitic material having an AEI-type framework structure, wherein more preferably the zeolitic material consists of a zeolitic material having an AEI-type framework structure. 36. The process of embodiment 35, wherein the zeolitic material having an AEI-type frame- work structure comprised in the seed crystals is selected from the group consisting of SSZ-39, SAPO-18, SIZ-8, including mixtures of two or more thereof, wherein preferably the zeolitic material having an AEI-type framework structure comprised in the seed crystals is SSZ-39. 37. The process of embodiment 35 or 36, wherein the amount of seed crystals in the mixture prepared in (1) and heated in (2) ranges from 3 to 12 wt.-% based on 100 wt.-% of Si in the mixture prepared in (1) calculated as the element, preferably from 3.5 to 10 wt.-%, more preferably from 4 to 9 wt.-%, more preferably from 4.5 to 7 wt.-%, and more prefera- bly from 5 to 6 wt.-% based on 100 wt.-% of Si in the mixture prepared in (1) calculated as the element. DESCRIPTION OF THE FIGURES Fig.1 displays the cis (chemical structure on the left hand side) and trans (chemical struc- ture on the right hand side) isomers of N,N-dimethyl-3,5-dimethylpiperidinium hy- droxide. Fig.2 displays the results from catalyst testing using the AEI(100) zeolite samples from Reference Example 1 respectively loaded with different amounts of copper, wherein the N₂O conversion in % is plotted along the ordinate, and the temperature in °C is plotted along the abscissa. Fig.3 displays the results from catalyst testing using the AEI(20) zeolite samples from Ref- erence Example 1 respectively loaded with different amounts of copper, wherein the N₂O conversion in % is plotted along the ordinate, and the temperature in °C is plot- ted along the abscissa. EXPERIMENTAL SECTION Characterization methods XRD patterns were collected on a Rint-Ultima III (Rigaku) using a Cu Kα X-ray source (40 kV, 20 mA). Elemental analyses of the samples were performed on an inductively coupled plasma-atomic emission spectrometer (ICP-AES, Shimadzu ICPE-9000). Reference Example 1: Cu/AEI zeolite catalysts preparation The AEI-type aluminosilicate zeolites were prepared by using N,N-dimethyl-3,5-dimethylpiperi- dinium hydroxide with different cis :trans isomer (see Figure 1) ratios (SACHEM, Inc.) as or- ganic structure directing agent (OSDA). Fumed silica (Cab-O-Sil M5, Cabot) was added into the solution containing N,N-dimethyl-3,5-dimethylpiperidinium hydroxide, NaOH (8M, Wako) and ze- olite Y having an Si/Al atomic ratio of 2.4 (JRC-Z-HY4.8, JGC Catalysts and Chemicals Ltd). The suspension with the molar composition of 1 SiO₂: 0.017 Al₂O₃: 0.17 OSDA: 0.46 NaOH: 20 H₂O was transferred to a Teflon-lined stainless-steel autoclave and crystallized at 150 °C for 3 days under tumbling condition. The as-synthesized samples were recovered after filtering, washing and drying at 100 °C overnight. The framework structure type of the zeolitic material obtained was verified by X-ray diffraction. The samples prepared using the OSDA with 20% cis and 100% cis isomer (both obtained from SACHEM, Inc.) were designated as AEI(20) and AEI(100), respectively. The OSDA was re- moved by calcination at 600 °C in air for 6 h. Then, the calcined samples were exchanged with 2.5 M NH₄NO₃ aqueous solution at 80 °C for 3 h to obtain the NH4-form ones. To research the effect of Cu loading on the reaction performance, 1, 5 and 50 mmol/L Cu(NO₃)₂ solutions were used to exchange with the NH₄-type AEI(20) and AEI(100) zeolites at a 100 mL/g liquid-to-solid ratio stirring at 80 °C for 24 h. The suspension was filtered, washed, dried and calcined in air at 550 °C for 5 h. The obtained samples were noted as xCu/AEI(20) and xCu/AEI(100), where x means the concentration of the Cu(NO₃)₂ solution. The Si : Al and Cu : Al molar ratios of the re- spective samples are displayed in Table 1 below, together with the copper loading values as de- termined by ICP-AES. Table 1: Chemical composition of the samples obtained according to Reference Example 1 as obtained from ICP-AES.

Example 1: Catalytic testing The continuous oxidation of methane reaction was performed in a fixed-bed flow reactor. In each run, 100 mg of catalyst in a granular form (particle size 500−1000 μm) was charged into a quartz tube (inner diameter 4 mm), which was placed in an electric tube furnace. The catalyst was pretreated at 500 °C for 1 h in an Ar and steam flow. The reaction was conducted at the temperature ranging from 300 to 450 °C in a flowing gas mixture of CH4, N₂O, H₂O and Ar with flow rates of 10, 10, 2 and 3 mL·min⁻¹. The outlet gas, containing the products, unreacted CH₄ and N₂O were analyzed using two on-line gas chromatographs (GC; GC-2014, Shimadzu). One of the GCs was used with a Shincarbon ST 50/80 packed column (3 mm × 6 m) and a TCD de- tector. Specifically, GC-TCD with a methanizer was used to detect H₂, N₂O, CO, CO₂ and CH₄. As may be taken from the results from catalyst testing displayed in Figure 2, the AEI(100) zeo- lite samples (i.e. the AEI-type zeolite obtained using the cis isomer of N,N-dimethyl-3,5-dime- thylpiperidinium hydroxide) from reference Example 1 respectively loaded with different amounts of copper afford a comparatively low conversion of N₂O with methane up to a tempera- ture of about 350 °C. When increasing the temperature up to 400 °C, a substantial increase in the N₂O conversion rate is observed, wherein said increase is particularly apparent for the sam- ples having a higher copper loading. When further raising the temperature to 450 °C, said trend continues, wherein the samples with higher copper loadings lead to a significant increase in N₂O conversion, in particular for the sample displaying the higher loading, which reaches com- plete conversion of N₂O at 450 °C. On the other hand, the results from catalyst testing using the AEI(20) zeolite samples (i.e. the AEI-type zeolite obtained using the N,N-dimethyl-3,5-dimethylpiperidinium hydroxide at a cis : trans molar ratio of 0.25) from Reference Example 1 respectively loaded with different amounts of copper displayed in Figure 3 show distinctly different N₂O conversion rates depending on the temperature and the degree of loading with copper. Thus, although results at the lowest copper loading levels are comparable, the intermediate sample with regard to copper loading displays a somewhat higher N₂O conversion rate at 400 °C, yet a far lower N₂O conversion rate at 450 °C compared to the results displayed in Figure 2 for the corresponding copper loaded AEI(100) ze- olite sample. On the other hand, the sample with the highest copper loading displays a far higher N₂O conversion rate at 400°C comparted to the result obtained at that temperature for the corresponding copper loaded AEI(100) zeolite sample. Accordingly, it has surprisingly been found that the inventive process allows for the activation of N₂O to unprecedented levels for its controlled catalytic conversion. Furthermore, it has quite un- expectedly been found that depending on the cis : trans ratio of the N,N-dimethyl-3,5-dime- thylpiperidinium hydroxide used as OSDA in the synthesis of the AEI-type zeolite, the catalyst may display completely different N₂O activation degrees at comparable loading of copper, such that catalytic conversion may be fine-tuned depending on the required activity for a given reac- tion at a given temperature, thus affording not only a highly effective, but also a highly versatile process for the activation of N₂O for chemical conversion. Cited Literature: - US 5,958,370 - Moliner, M. et al. in Chem. Commun.2012, 48, pages 8264-8266 - Maruo, T. et al. in Chem. Lett.2014, 43, page 302-304 - Martín, N. et al. in Chem. Commun.2015, 51, 11030-11033 - Dusselier, M. et al. in ACS Catal.2015, 5, 10, 6078-6085 - US 2015/0118150 A1 - WO 2016/149234 A1 - Ransom, R. et al. in Ind. Eng. Chem. Res.2017, 56, 4350−4356 - WO 2018/113566 A1 - WO 2020/098796 A1 - WO 2018/234044 A1 - Memioglu, O. et al. in Chem. Comm.2021, 57, 1364-1367 - WO 2017/134007 A1 - US 2016/264428 A1

Claims

Claims 1. A process for the activation of N₂O comprising (i) providing a gas stream comprising N₂O; (ii) contacting the gas stream provided in (i) with a catalyst at a temperature in the range of from 300 to 600 °C, wherein the catalyst comprises a zeolitic material having the AEI-type framework structure, wherein the framework structure of the zeolitic material comprises SiO₂ and Al₂O₃, and wherein the zeolitic material contains copper. 2. The process of claim 1, wherein the gas stream in (i) contains N₂O in an amount ranging from 1 to 100 vol.-%. 3. The process of claim 1 or 2, wherein the gas stream in (i) further comprises a reducing agent, wherein the reducing agent is selected from the group consisting of hydrocarbons. 4. The process of any of claims 1 to 3, wherein in (ii), contacting the gas stream provided in (i) with a catalyst is carried out at a temperature in the range of from 350 to 550 °C. 5. The process of any of claims 1 to 4, wherein the zeolitic material having the AEI-type framework structure is ion exchanged with copper. 6. The process of any of claims 1 to 5, wherein the zeolitic material having the AEI-type framework structure contains copper in an amount in the range of from 0.1 to 12 wt.-% based on 100 wt.-% of the zeolitic material having the AEI-type framework structure, wherein copper is calculated as the element. 7. The process of any of claims 1 to 6, wherein the zeolitic material having the AEI-type framework structure comprised in the catalyst is prepared by a process comprising (1) preparing a mixture comprising one or more sources of SiO₂, a first zeolitic material comprising SiO₂ and Al₂O₃ in its framework structure and having an FAU-type framework structure, one or more cationic structure directing agents, and water; (2) heating the mixture obtained in (1) for obtaining a second zeolitic material compris- ing SiO₂ and Al₂O₃ in its framework structure and having an AEI-type framework structure 8. The process of claim 7, wherein the one or more cationic structure directing agents are selected from the group consisting of N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpyrrolidinium , N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylpiperidinium, N,N-di(C₁-C₄)alkyl-3,5-di(C₁-C₄)alkylhex- ahydroazepinium, and mixtures of two or more thereof. 9. The process of claim 8, wherein the cis : trans molar ratio of the cis isomer to the trans isomer in the one or more cationic structure directing agents relative to the alkyl groups at the 3 and 5 positions of the heterocyclic amine ring is in the range of from 0.01:1 to 0.95:1. 10. The process of claim 8, wherein the trans : cis molar ratio of the trans isomer to the cis isomer in the one or more cationic structure directing agents relative to the alkyl groups at the 3 and 5 positions of the heterocyclic amine ring is in the range of from 1:1 to 0:1. 11. The process of any of claims 7 to 10, wherein the one or more sources of SiO₂ is selected from the group consisting of fumed silica, silica hydrosols, reactive amorphous solid sili- cas, silica gel, silicic acid, water glass, sodium metasilicate hydrate, sesquisilicate, disili- cate, colloidal silica, silicic acid esters, and mixtures of two or more thereof. 12. The process of any of claims 7 to 11, wherein the mixture prepared in (1) further com- prises OH-. 13. The process of claim 12, wherein the OH- : Si molar ratio of hydroxide to Si contained in the mixture prepared in (1) is in the range of from 0.01 to 5. 14. The process of any of claims 7 to 13, wherein the mixture prepared in (1) contains water at an H₂O : Si molar ratio in the range of from 1 to 60. 15. The process of any of claims 7 to 14, wherein heating in (2) is conducted under autoge- nous pressure, preferably under hydrothermal conditions.