Activity patterns of metal oxide catalysts in the synthesis of N-phenylpropionamide from propanoic acid and aniline

Abstract

The reactivities of various commercial and lab-made oxide samples (e.g., γ-Al 2 O 3 , CeO 2 , ZrO 2 and TiO 2 ) in the heterogeneous catalytic synthesis of N-phenylpropionamide (T, 383 K) from aniline and propanoic acid have been investigated. All the materials studied drive the direct synthesis of the amide to an extent depending on both the chemical and structural properties. A 0th-order kinetic dependence on the substrate concentrations suggests that the reaction proceeds via a Langmuir-Hinshelwood (L-H) pathway under kinetic control of the adsorption-desorption steps (the rate determining step, r.d.s.). The comparative analysis of the activity data on the basis of the relative surface specific kinetic constant discloses a superior surface reactivity of TiO 2 , CeO 2 and ZrO 2 over the γ-Al 2 O 3 system, and also highlights marked differences in the catalytic functionality of the titania samples. IR spectroscopic studies of the carboxylic acids and amine adsorption and interaction patterns show the formation of the bidentate, bridging, and unidentate carboxylate intermediates accounting for the different amidation functionalities of the studied materials.

Critical role of additive-induced molecular interaction on the operational stability of perovskite light-emitting diodes

“…This can be rationally interpreted from previously reported cases of catalytic amidation between amino and carboxyl groups by the solid-base properties of ZnO. [33][34][35] We show a schematic illustration of the catalytic amidation from the formed ion pairs between the AAC molecules and the excessive FA + cations in Fig- ure 3D. Generally, for the solution-processed ZnO films, there are unsaturated Lewis acid-base pairs on the imperfect surface, of which the exposed Zn 2+ cations and the O 2À anions act as Lewis acid and Lewis base sites, respectively.…”

The enhancement of direct amide synthesis reaction rate over TiO 2 @SiO 2 @NiFe 2 O 4 magnetic catalysts in the continuous flow under radiofrequency heating

“…This study follows our previous work [20,28,31] where we developed different titaniacontaining composite catalysts for this reaction. The main problems with these catalysts were (i) the relatively fast catalyst deactivation due to product inhibition, as a result of a strong product adsorption on the titania surface and (ii) limited reaction rate.…”

“…Chaudhari et al [30] studied the amide synthesis over acids and sulfated tungstates, and identified that catalytic activity significantly depends on the acid type. Arena et al [31] showed the following reaction rate sequence is observed TiO2 (P25) > ZrO2 ≈ CeO2 > γ-Al2O3 caused by the chemical and surface properties of the catalysts. To the best of our knowledge however, there is very little systematic studies about the effect of sulfation treatment on the direct amide synthesis reaction rates to allow for efficient catalyst development.…”

Recent developments in catalytic amide bond formation

“…Heterogeneous catalysts employing other transition metals are also known and can offer simpler alternatives to systems that require intricate ligands. Iron [97] and various metal oxides [98] (most successfully TiO ) supported on silica having been reported, under neat conditions for the former free system. [97] Another report of heterogeneous catalysis employed silver/iron nanoparticles.…”