Oxidation of Alcohols to Aldehydes and Ketones

Base-Free Aerobic Oxidation of Alcohols over Copper-Based Complex under Ambient Condition

“…The selective oxidation of alcohols to aldehydes and ketones is among the most important reactions in both organic synthesis and the chemical industry because the products are precursors and intermediates of many drugs, fine chemicals, vitamins, and fragrances. − O 2 or air is a very attractive alternatives to traditional stoichiometric oxidants such as chromium salts, activated DMSO, peroxides, , and hypervalent iodines . Many heterogeneous , and homogeneous , catalysts have been developed using different metals, such as Ru, , Pd, Co, Cu, Pt, Rh, V, Os, Ce, Ni, Mo, and Au. , However, to the best of our knowledge, efficient oxidation of alcohols requires elevated temperature or adding external alkali such as potassium tert -butylate, carbonate, , and organic base .…”

Redox Layer Deposition of Thin Films of MnO2 on Nanostructured Substrates from Aqueous Solutions

“…[39][40][41][42] Such morphology of the layer could be a result of partial solubilization of the film, 43 a different packing density of precursor molecules on certain faces of the growing MnOx layer or a high aspect ratio of the seed crystals generated at the beginning of deposition. 44,45 Furthermore, the sheet-like morphology could also arise due to a side reaction between PA molecules and the manganese oxide deposited during the previous deposition cycle: 46 followed by removal of the loose Mn(OH)2 during the washing step. Although oxidation of unsaturated alcohols with MnO2 typically requires more than 1 h of exposure time, vigorous shaking and nearly anhydrous conditions (in this case excess of water results in deactivation of MnO2), 46 a small degree of this reaction could nevertheless occur between the PA molecules in 0.1 M solution and the as-deposited manganese oxide, forming point defects in the coating layer.…”

“…44,45 Furthermore, the sheet-like morphology could also arise due to a side reaction between PA molecules and the manganese oxide deposited during the previous deposition cycle: 46 followed by removal of the loose Mn(OH)2 during the washing step. Although oxidation of unsaturated alcohols with MnO2 typically requires more than 1 h of exposure time, vigorous shaking and nearly anhydrous conditions (in this case excess of water results in deactivation of MnO2), 46 a small degree of this reaction could nevertheless occur between the PA molecules in 0.1 M solution and the as-deposited manganese oxide, forming point defects in the coating layer. Acting as natural nucleation sites, these defects could promote the 3D morphology of the layer observed after higher number of deposition cycles.…”

“…It is worth noting that the corrosion inhibition studies of iron in HCl showed an actual increase in PA adsorption with temperature due to the formation of polymeric PA films at higher temperature 27,78 (polymerization of PA was also reported in the pure aqueous solution heated at 95 o C). 22 From the kinetic point of view, although the increase of temperature decreases the time needed to reach the adsorption equilibrium, it may also accelerate the side reaction of PA with the as-deposited MnO2, 46 which could decrease the saturation GPC and increase porosity of the end material. Therefore, the effect of temperature on the growth of the layer remains open for further investigations.…”

Metal-free mechanochemical oxidations in Ertalyte® jars

“…The conversion of primary and secondary alcohols to the corresponding carbonyl compounds (aldehydes and ketones, respectively) is of such importance in organic chemistry that it finds very few parallels in other synthetic organic processes [1–2]. These transformations can be achieved by using a wide range of oxidizing reagents [3], but most of them are difficult-to-handle and suffer from waste problems due to large amounts of byproducts, thus decreasing the atom efficiency [4–5]. The discovery of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, commonly known as TEMPO by Lebedev and Kazarnowskii in 1960 has been hailed as a significant breakthrough in the field of redox reactions, allowing the fast and selective oxidation of alcohols to the related carbonyl compounds under very mild conditions [6–7].…”