Selective Production of Secondary Amine by the Photocatalytic Cascade Reaction Between Nitrobenzene and Benzyl Alcohol over Nanostructured Bi₂MoO₆ and Pd Nanoparticles Decorated with Bi₂MoO₆

Abstract

The synthesis of secondary amine by the photoalkylation of nitrobenzene with benzyl alcohol using a simple light source and sunlight is a challenging task. Herein, a onepot cascade protocol is employed to synthesize secondary amine by the reaction between nitrobenzene and benzyl alcohol. The one-pot cascade protocol involves four reactions: (a) photocatalytic reduction of nitrobenzene to aniline, (b) photocatalytic oxidation of benzyl alcohol to benzaldehyde, (c) reaction between aniline and benzaldehyde to form imine, and (d) photocatalytic reduction of imine to a secondary amine. The cascade protocol to synthesize secondary amine is accomplished using Bi 2 MoO 6 and Pd nanoparticles decorated Bi 2 MoO 6 catalysts. The surface characteristics, oxidation states, and elemental compositions of the materials are characterized by several physicochemical characterization techniques. Optoelectronic and photoelectrochemical measurements are carried out to determine the bandgap, band edge potentials, photocurrents, charge carrier's separation, etc. An excellent yield of secondary amine is achieved with simple household white LED bulbs. The catalyst also exhibits similar or even better activity in sunlight. The structureactivity relationship is established using catalytic activity data, control reactions, physicochemical, optoelectronic characteristics, and scavenging studies. Bi 2 MoO 6 and Pd nanoparticles decorated Bi 2 MoO 6 exhibit excellent photostability and recyclability. The simple catalyst design with a sustainable and economical light source for the synthesis of useful secondary amine from the nitrobenzene and benzyl alcohol would attract the researchers to develop similar catalytic protocols for other industrially important chemicals.

Simultaneous Pd Nanoparticle Deposition and Enhancement in the Surface Oxygen Vacancy of Bi2MoO6 Nanoflakes for Room Temperature Vanillin Hydrodeoxygenation

“…These peaks could be best fitted by the combination of four peaks with binding energies of 334.6, 336.1, 340.0, and 341.7 eV. The peaks at 334.6 and 340.0 eV are attributed to the Pd 0 species while the remaining two peaks at 336.1 and 341.7 eV ascribe to the Pd 2+ species in Pd(1%)/BMO nanoflakes. , It could be concluded here that for catalytic transformation, a significant amount of Pd 0 species is present in Pd(1%)/BMO nanoflakes. The presence of Pd was further confirmed by the surface atomic concentration of Pd over various synthesized catalysts (Table S1).…”

“…In the BMO sample, two peaks located at 232.3 and 235.5 eV could be assigned to Mo 6+ 3d 5/2 and 3d 3/2 electronic configurations, respectively. For the Pd(1%)/BMO sample, these peaks slightly shifted to 232.0 and 235.3 eV for 3d 5/2 and 3d 3/2 electronic configurations, respectively . This shift in binding energy resulted due to the formation of reduced Mo (6– x )+ sites in the Pd(1%)/BMO nanoflakes .…”

Metal‐Free N‐Doped Carbon Catalyst Derived from Chitosan for Aqueous Formic Acid‐Mediated Selective Reductive Formylation of Quinoline and Nitroarenes

“…The yellow material was poured into a mortar pestle, grounded into a powder, and designated g-C 3 N 4. [43] Synthesis of cellulose-derived carbon catalyst 1 g cellulose was charged in an alumina boat and mounted in a tubular furnace. The material was subjected to carbonization at the ramp rate of 5 °C min À 1 up to desired temperature in a static Ar environment for 1 h. The resultant black material was grounded into powder and designated as C CEL .…”

In Situ Construction of Single-Site Ti Active Centers on Carbon Nitride for Photocatalytic Chemoselective Hydrogen Transfer Reduction

“…4,20−24 More importantly, the redox process involving photogenerated electrons and holes in the photocatalytic process provides a possibility for the coupled reaction of the reduction of nitroaromatics with the oxidation of some organic compounds (such as aromatic alcohols), 25−27 as well as the coupling of oxidation and reduction products (condensation of aromatic amines and aromatic aldehydes for the formation of imine) to obtain important organic compounds. 28 For these reactions, in addition to the environmental problems and efficiency, more attention should be paid to the chemical selectivity of some nitro compounds containing sensitive functional groups (such as C�C, C�C, C�O, C�N, C�N, C−X (X is halogen)). Because the functional group is an important component of some special compounds and its existence allows further functionalization through cross-coupling or related chemistry, the efficient and green chemoselective reduction of substituted nitroaromatics to aromatic amines is very important but still a challenge.…”

“…Recently, many studies have been devoted to the development of efficient, highly selective, and green catalytic systems for the selective reduction of nitroaromatics. In particular, heterogeneous photocatalysis has attracted much attention due to its advantages of recyclability, using sunlight, low energy consumption, and mild reaction conditions. − Many photocatalytic materials have been widely reported for the photocatalytic reduction of nitro compounds through direct reduction with water, , hydrogenation with H 2 as a reductant, , and the hydrogen transfer reduction reaction with other sacrificial agents. ,− More importantly, the redox process involving photogenerated electrons and holes in the photocatalytic process provides a possibility for the coupled reaction of the reduction of nitroaromatics with the oxidation of some organic compounds (such as aromatic alcohols), − as well as the coupling of oxidation and reduction products (condensation of aromatic amines and aromatic aldehydes for the formation of imine) to obtain important organic compounds . For these reactions, in addition to the environmental problems and efficiency, more attention should be paid to the chemical selectivity of some nitro compounds containing sensitive functional groups (such as CC, CC, CO, CN, CN, C–X (X is halogen)).…”