MnO2 nanostructures as sustainable catalysts for selectivity tuning and syntheses of amine coupling products with bio-derived glycerol

Valorization of bio-renewable glycerol by catalytic amination reactions

“…53 Subsequently, the same group reported a crystalline MnO 2 nanocatalyst for the preparation of various N -formamides under aerobic conditions using glycerol. 54 The selectivity of the reaction can be tuned using mixed crystalline MnO 2 nanomaterials and their surface Mn( iii )/Mn( iv ) species ratios. In the presence of α- and γ-MnO 2 the N -formamide product with high selectivity was obtained, while β- and δ-MnO 2 gave the mixture of N -formamide and N -methylamine in equal ratio.…”

“…Quite recently, Bhanage and co-workers prepared N -methylamines employing β-MnO 2 as a catalyst in the presence of a higher amount of glycerol. 54 Under optimized conditions (0.5 mmol amine, 10 mmol glycerol, 30 mg β-MnO 2 , 10 bar air : O 2 (9 : 1), 100 °C, 5 mL dioxane, 12 h), aliphatic secondary amines reacted well with glycerol and obtained the corresponding N -methylated products in average yields (24–58%) (Scheme 9). Primary amine such as aniline failed to deliver the corresponding N -methylamine product under standard conditions.…”

“…The presence of oxidative conditions is important in order to convert Mn( iii ) into Mn( iv ), which is necessary to obtain the catalytic cycle. 54…”

Fe‐catalyzed Selective N‐Formylation Protocol for Amines Using Glycolic Acid as C1 Bio‐Building Block

“…Our group explored different MnO 2 phases for their redox properties and effect on aerobic synthesis of different amine coupling products with glycerol. [27] Additionally, our group further contributed where we developed a catalystfree, mild syntheses processes for syntheses of N-formamides exploring 5 different feedstocks with DHA & glyoxal performing at peak as building blocks. [28] Flynn et al [29] developed a mild, aerobic oxidative process for glycolaldehyde as a C1 building block for syntheses of N-formamides, however, this process was only limited to secondary amines.…”

“…Prior literature reports involve Shi and group [25,26] applying glycerol and its derivatives such as 1,3‐dihydroxyacetone (DHA) as carbon sources for syntheses of N ‐formamides using Cu‐based catalysts. Our group explored different MnO 2 phases for their redox properties and effect on aerobic synthesis of different amine coupling products with glycerol [27] . Additionally, our group further contributed where we developed a catalyst‐free, mild syntheses processes for syntheses of N ‐formamides exploring 5 different feedstocks with DHA & glyoxal performing at peak as building blocks [28] .…”