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Commercial SSZ‐13 zeolite with different n(Si)/n(Al) ratios and from different suppliers were subjected to a post‐synthetic treatment in order to create mesopores of up to 15 nm. Furthermore, the materials were modified with copper ions and thoroughly physico‐chemically characterized. The modified textural properties varied the nature of copper species, and thus, activity in the selective catalytic reduction of NOx with ammonia (NH3‐SCR‐DeNOx). Pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) studies with hexane as probe liquid revealed improved intracrystalline diffusion for some Cu‐containing SSZ‐13 materials. The NH3‐SCR‐DeNOx pathways are verified via in situ DR UV‐Vis, in situ FT‐IR and EPR, temperature‐programmed studies as well as SSITKA studies that provide a mechanistic understanding of the reaction. Kinetic modelling results demonstrate the highest NH3‐SCR‐DeNOx reaction rates and up to 20 % lower energy barriers with n(Si)/n(Al) ratio of 6.5 for all modified forms (i. e., (NH4)Cu‐SSZ‐13_6.5 and Cu‐SSZ‐13_6.5_NaOH/0.1) and cause only negligible parasitic ammonia oxidation. The modelling of the stop‐flow experiments further demonstrates that the SCR pathway via the HONO surface intermediate is present but barely contributes to the overall NO conversion compared to the dominant path between adsorbed NH3 and NO from the gas phase. [ABSTRACT FROM AUTHOR]

The development of a sustainable and simple catalytic system for N‐formylation of N‐heterocycles with methanol by direct coupling remains a challenge, owing to many competing side reactions, given the sensitivity of N‐heterocycles to many catalytic oxidation or dehydrogenation systems. This work concerns the development of an in situ‐generated CuI catalytic system for oxidative N‐formylation of N‐heterocycles with methanol that is based on the case study of a more typical 1,2,3,4‐tetrahydroquinoline as substrate. Aside from N‐heterocycles, some acyclic amines are also transformed into the corresponding N‐formamides in moderate yields. Furthermore, a probable reaction mechanism and reaction pathway are proposed and extension of work based on some findings leads to a demonstration that the formed ⋅O2− and ⋅OOH radicals in the catalytic system is related to the formation of undesired tar‐like products. [ABSTRACT FROM AUTHOR]

Biomass derived glycolaldehyde was employed as C1 building block for the N‐formylation of secondary amines using air as oxidant. The reaction is atom economic, highly selective and proceeds under catalyst free conditions. This strategy can be used for the synthesis of cyclic and acyclic formylamines, including DMF. Mechanistic studies suggest a radical oxidation pathway. [ABSTRACT FROM AUTHOR]

Commercial SSZ-13 zeolite with different n(Si)/n(Al) ratios and from different suppliers were subjected to a post-synthetic treatment in order to create mesopores of up to 15 nm. Furthermore, the materials were modified with copper ions and thoroughly physico-chemically characterized. The modified textural properties varied the nature of copper species, and thus, activity in the selective catalytic reduction of NO x with ammonia (NH 3 -SCR-DeNO x ). Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) studies with hexane as probe liquid revealed improved intracrystalline diffusion for some Cu-containing SSZ-13 materials. The NH 3 -SCR-DeNO x pathways are verified via in situ DR UV-Vis, in situ FT-IR and EPR, temperature-programmed studies as well as SSITKA studies that provide a mechanistic understanding of the reaction. Kinetic modelling results demonstrate the highest NH 3 -SCR-DeNO x reaction rates and up to 20 % lower energy barriers with n(Si)/n(Al) ratio of 6.5 for all modified forms (i. e., (NH 4 )Cu-SSZ-13_6.5 and Cu-SSZ-13_6.5_NaOH/0.1) and cause only negligible parasitic ammonia oxidation. The modelling of the stop-flow experiments further demonstrates that the SCR pathway via the HONO surface intermediate is present but barely contributes to the overall NO conversion compared to the dominant path between adsorbed NH 3 and NO from the gas phase., (© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.)