Cobalt‐Copper Nanoparticles Catalyzed Selective Oxidation Reactions: Efficient Catalysis at Room Temperature

Abstract

Bimetallic nanoparticles (NPs) play a pivotal role in promoting high activity and selectivity towards various industrially important reactions in comparison to single metal NPs due to their modulated electronic and surface properties. Herein, we report the synthesis of non‐precious CoCu NPs, which serve as an excellent catalyst for the selective oxidation of a wide range of electronically diverse benzyl alcohols to benzaldehydes, in the presence of tert‐butyl hydroperoxide (TBHP) as an oxidant at room temperature. The excellent catalytic activity of CoCu NPs is ascribed to a two‐fold synergistic effect arising from the combination of enhanced peroxide decomposition, active Co2+ catalyst regeneration driven by the faster redox processes (between Co3+ and Cu+), and a feasible cobalt dimerisation‐regeneration process. The recoverability and reusability of CoCu NPs are also demonstrated. With the merits of low‐cost and recyclable catalysis under mild conditions, the present catalyst represents an efficient and potential alternative to precious metal catalysts.

A Stable Polyoxometalate-Based Metal–Organic Framework as Highly Efficient Heterogeneous Catalyst for Oxidation of Alcohols

“…Whereafter, this catalytic system was proceeded under O 2 and N 2 atmospheres, respectively, but no obvious difference could be observed, which indicated that O 2 molecules did not participate in the process (Table S5, entries 1–3). On the basis of the observations above, a possible reaction mechanism in Scheme was proposed according to the literatures . Initially, TBHP ( t BuOOH) reacted with Cu sites of POM-Cu­(Ι) catalyst in a so-called Haber–Weiss catalytic mechanism, resulting in a transformation from t BuOOH into tert -butoxyl ( t BuO·) radical and hydroxyl ion (OH – ). , Subsequently, accompanied by the leaving of a t BuOH, the generated t BuO· interacted with 1-phenylethanol to form the radical ( 1 ), which would convert into the intermediate ( 2 ) with the effect of Cu­(ΙΙ) sites in HENU-1 .…”

“…The oxidation of alcohols into carbonyl compounds is a frequently important research topic in the laboratory, for aldehyde/​ketone products take up the key position in the chemical industry including the fine chemical and pharmaceutical industry. , Traditionally, various stoichiometric amounts of oxidizing agents (e.g., MnO 2 , CrO 3 , SeO 2 , KMnO 4 , K 2 Cr 2 O 7 , etc.) have been widely used in industry but under severe conditions such as high pressure or temperatures and/or with strong mineral acids . Also, a mass of environmentally harmful toxic inorganic salts is usually generated from these chemical transformations .…”

Synthesis and Structures of Ruthenium Carbonyl Complexes Bearing Pyridine-Alkoxide Ligands and Their Catalytic Activity in Alcohol Oxidation

“…Compared with above oxidants, tert -butyl hydroperoxide (TBHP) is an alternative suitable oxidant and widely used in oxidation reactions, particularly in olefin epoxidation (Chen and Luck, 2016; Kashani et al, 2018) and C–H bond oxidation (Murahashi et al, 2000; Kudrik and Sorokin, 2017; Sarma et al, 2018). There are also some successful examples of using TBHP as an external oxidant in alcohol oxidation (Sarkar et al, 2014; Annunziata et al, 2018; Borah et al, 2018). In spite of this progress, less attention has been paid to this research area.…”

Mild Liquid Phase Oxidation of Benzyl Alcohol in the Presence of Microporous Framework Copper Silicates

“…Hence, the copper silicates promoted tBuOOH activation, which may give tert-butylperoxyl, tert-butoxyl and hydroxyl radicals (Equations 1, 2), [35][36][37][38][39] in line with different transitions metal-catalysed peroxidative oxidation reactions. [40][41][42] The radicals may react with BzOH (RCH 2 -OH in Equations 3, 4) giving benzyl alcohol radicals (RCH · -OH in Equations 5-7), [18,38,43] and subsequently BzAld (RCHO). [38,43] According to the literature for BzOH reaction with molecular oxygen, BzOH inhibits BzAcid formation.…”

“…[40][41][42] The radicals may react with BzOH (RCH 2 -OH in Equations 3, 4) giving benzyl alcohol radicals (RCH · -OH in Equations 5-7), [18,38,43] and subsequently BzAld (RCHO). [38,43] According to the literature for BzOH reaction with molecular oxygen, BzOH inhibits BzAcid formation. [44] Since considerable amounts of BzAcid were formed in the presence of the copper silicates, one may neglect the influence of molecular oxygen in BzAcid formation.…”