Hydrogen Peroxide as a Green Oxidant for the Selective Catalytic Oxidation of Benzylic and Heterocyclic Alcohols in Different Media: An Overview

Abstract

Among a plethora of known and established oxidant in organic chemistry, hydrogen peroxide stands in a special position. It is commercially and inexpensively available, highly effective, selective, and more importantly it is compatible with current environmental concerns, dictated by principles of green chemistry. Several chemicals or their intermediates that are important in our daily life such as pharmaceuticals, flavors, fragrances, etc. are products of oxidation of alcohols. In this review, we introduce hydrogen peroxide as an effective, selective, green and privileged oxidant for the catalyzed oxidation of primary and secondary benzylic and heterocyclic alcohols to corresponding carbonyl compounds in different media such as aqueous media, under solvent-free conditions, various organic solvent, and dual-phase system.

Redox Active Hexanuclear Mixed Valence Dicationic Ce(III)/Ce(IV) Coordination Clusters

“…Our report is the second example Ce‐ion catalyzed TEMPO free oxidation of benzyl alcohol [ 35 ] although there are several previously reported synthetic methods of TEMPO free oxidation alcohols to aldehydes. [ 36–37 ] To have an insight into the reaction mechanism, the UV/Vis and ESI mass spectrometric techniques were utilized. Complex 3 2+ (NO 3 – ) 2 was treated with O 2 using a balloon at 100 °C in DMF for 5 h and its UV/Vis spectrum and ESI mass spectrum were recorded and compared with those of the freshly prepared DMF solution of 3 2+ (NO 3 – ) 2 .…”

“…There are several other examples of TEMPO free oxidations of alcohols. [ 36–37 ] Hydrogen peroxide (H 2 O 2 ) was utilized as an oxidizing agent along with several catalysts. [ 37 ] Several other metal‐based catalysts were also utilized for O 2 mediated TEMPO free oxidation of alcohols nearly one and half decades ago.…”

“…[ 36–37 ] Hydrogen peroxide (H 2 O 2 ) was utilized as an oxidizing agent along with several catalysts. [ 37 ] Several other metal‐based catalysts were also utilized for O 2 mediated TEMPO free oxidation of alcohols nearly one and half decades ago. [ 36 ] Very recently, both peroxide bridged dinuclear Ce(IV) and monomeric Ce(III) complexes were shown to oxidise the aromatic alcohols to their corresponding aldehydes in high yields.…”

Activated carbon supported Co1.5PW12O40 as efficient catalyst for the production of 1, 2 cyclohexane diol by oxidation of cyclohexene with H2O2 in the presence of CO2

“…Both are clean and cheap but it is evident that O 2 is the ideal oxidant to be used. However, O 2 is rarely used because it is kinetically inert and requires harsh conditions of temperature and/or pressure to be activated (14). H 2 O 2 is a highly efficient oxidant with an active oxygen content of 47.1 wt% (15) but it can decompose dangerously if used in high concentrations.…”

“…H 2 O 2 is considered as a green oxidant because it only produces H 2 O as a by-product. This is why it is widely used in the chemical industry and in environmental protection (16)(17)(18). Although many reactions can be obtained using O 2 , the use of H 2 O 2 as an oxidant has the advantage of carrying out reactions under milder conditions.…”