1 research outputs found
UV Cross-Linked Polymer Stabilized Gold Nanoparticles as a Reusable Dip-Catalyst for Aerobic Oxidation of Alcohols and Cross-Aldol Reactions
In this work, a gold nanoparticle (AuNP)-embedded composite
polymer
membrane for dip-catalysis is developed. Primarily, a polyvinylpyrrolidone-stabilized
AuNP (PVP-AuNP) with an average size of 6.50 nm was synthesized by
the reduction of a composite solution of Au salt and PVP. Next, the
composite membrane was fabricated by simply depositing the PVP-AuNP
on the Nylon membrane followed by UV cross-linking. The composite
membrane having the cross-linked PVP-AuNP was utilized as a dip-catalyst
for the aerobic oxidation of alcohols to carbonyl compounds under
oxygen and clean reaction conditions. The catalyst was further tested
for performing cross-aldol reactions. The PVP-AuNP-catalyzed oxidation
reaction also has other noteworthy characteristics, such as a low
catalyst loading (Au, 1.2 mol %), high yield, and selectivity with
a broad substrate scope (aliphatic, aromatic, biphenyl, and heterocyclic
alcohols). The turnover number (TON) and turnover frequency (TOF)
for the oxidation reaction of the alcohol are calculated to be 74.5
and 12.41 h–1, respectively. The P4VP-AuNP dip-catalysts
are highly stable under the reaction conditions without significant
leaching of Au into the solution. The dip-catalyst demonstrates outstanding
reusability up to 10 catalytic cycles while maintaining high catalytic
performance and structural features. It can be easily recovered by
simply pulling it out from the reaction mixture once the reaction
is complete, followed by washing and drying. The practical usefulness
of the suggested method was further demonstrated by the PVP-AuNP-catalyzed
gram-scale synthesis of high-value chemicals like acetophenone. Although
the AuNPs are already used for different reactions, their integration
into dip-catalysts for oxidation of alcohols and cross-aldol reactions
with a wide substrate scope is rare. Overall, these findings demonstrate
that developing composite dip-catalyst systems is a realistic strategy
for creating high-value chemicals in a sustainable and environmentally
friendly way