Formal arylation of NH₃ to produce diphenylamines over supported Pd catalysts

Abstract

In the presence of supported Pd nanoparticle catalysts, e.g., Pd/AlO, various diphenylamines could be synthesized through acceptorless formal arylation using NH or its surrogates, e.g., urea, as nitrogen sources and cyclohexanones as arylation sources. The observed catalysis was truly heterogeneous, and the catalyst was reusable with retention of its high catalytic performance.

Elucidating the Role of Rh/C on the Pathways and Kinetics of Ketone‐to‐Secondary Amines Reaction

“…Their results suggest that the reaction proceeds according to the general steps described by Taniguchi et al [17] . and Koizumi et al., [18] in which the product distribution is affected by the hydrogenation of the imine to form cyclohexylamine or its dehydrogenation to form aniline. However, no analysis has been performed to study the kinetically relevant step or plausible reaction mechanism.…”

“…The ketone condenses with the amine to produce an imine intermediate ( 3 ), which is subsequently converted into the desired amine ( 4 ) via hydrogenation or dehydrogenation (Scheme 1). [17,18] This process usually implies the formation of side products (tertiary amines, alcohols, etc.) and thus, catalytic materials must be used to control the selectivity toward the desired product [15,19–21] …”

Experimental protocol for the study of One-pot amination of Cyclohexanone-to-secondary amines over Carbon-supported Pd

“…In this sense, the sustainable transformation of lignocellulose-based substrates (e.g., aldehydes, ketones, phenols, alkenes and alkynes) into amines have been reported as a promising way to replace oil from its actual applications [6] , [7] , [8] , [9] . Among them, the heterogeneously catalyzed reductive amination of ketones has drawn great attention as a method for the synthesis of primary or higher-order amines [10 , 11] . This paper describes a protocol based on our research on Liquid phase amination of Cyclohexanone-to-Secondary amines over Carbon-supported Pd catalysts.…”

Selective Synthesis of Primary Anilines from NH3 and Cyclohexanones by Utilizing Preferential Adsorption of Styrene on the Pd Nanoparticle Surface

“…[8] Since the direct use of NH 3 as an itrogen source in chemical synthesis is attractive from the viewpoints of step and atom economy, [9] thed evelopment of the direct conversion of NH 3 and cyclohexanones into primary anilines is an important task. [10] However,c onsidering the results obtained for the dehydrogenative aromatization strategy [5] including our previous studies, [8,11,12] there is acritical issue in achieving the selective synthesis of primary anilines;i .e., the desired primary anilines are typically more reactive than NH 3 for the condensation with cyclohexanone substrates,r eadily affording the corresponding imines (i.e., N-cyclohexylidene-anilines) (step 2, Figure 1a). Then, the imines are reduced via the transfer of hydrogen from the primary aniline production, thereby affording undesirable N-cyclohexylanilines (step 3, Figure 1a).…”