Oxidation of benzyl alcohols by nitrous and nitric acids in strong sulfuric acid media

Abstract

We have studied the oxidation of benzyl alcohols by nitrous and nitric acid in sulfuric acid media. The oxidation by nitrous acid is rapid and has an activation energy of 10.6 -t 0.8 kcal mol-'. A Hammett plot of logkp vs. u -is linear with a p value of -1.4. The oxidation by nitric acid in sulfuric acid media is autocatalytic. From the kinetic and product analyses, it is concluded that a common oxidant, the nitrosonium ion is involved when either nitrous or nitric acid is used. A mechanism is proposed which involves the abstraction of hydride from the alcohols as the rate determining step. It is demonstrated that the autoxidation of the alcohols is catalyzed by nitrous acid or nitric oxide.

Aerobic Alcohol Oxidations Mediated by Nitric Acid

“…An induction period was observed which could be eliminated by the addition of small amounts of NaNO 2 ( Figure 1, curves a-c). This observation-known from the literature [12] -points towards the crucial role of HNO 2 , which is formed upon protonation of NO 2 À . Inhibition of the reaction in the presence of urea-a known HNO 2 trap [14] -is in line with this hypothesis.…”

“…This partial oxidation is not only a model reaction of interest to (fine-)chemical synthesis, [12] the selectivity of this reaction is also very sensitive to radical side-reactions which easily cause over-oxidation of PhCHO to benzoic acid (PhCOOH). [13] Selective aerobic alcohol oxidations with catalytic amounts of HNO 3 could offer an attractive metalfree alternative to precious-metal-catalyzed systems.…”

Selective Aerobic Oxidation of Benzylic Alcohols Catalyzed by Carbon‐Based Catalysts: A Nonmetallic Oxidation System

“…Nitric acid is one of the most commonly produced compounds in the chemical industry and has been studied intensively as an oxidizing agent for alcohol oxidation. These reactions were carried out either with concentrated acid (sulphuric acid or nitric acid) as the reaction media12a,b or with NaNO 2 as the catalyst 12c. Therefore it could be postulated that nitric acid ultimately serves as the oxidant in NACOS.…”

Effect of pH conditions on the depolymerization of Wucaiwan coal by mixed acids/ultrasound method and the product structures and performance

“…Then, the aliphatic hydrocarbons linked with oxygen-containing groups such as nitro group, mineral salts, and small aromatic molecules distributed between the gaps of the first phase was dissolved in water phase when washing the system to pH = 0.012. As the washing number increase (pH = 1.99-4.09), the rest of the sediment depolymerized, and the depolymerized coal samples are composed of only aromatic compound linked with more oxygen-containing groups including hydroxyl, carboxyl, ester, carbonyl, nitro, and sulfonic groups, possessing the annulus wall of multilayer graphene fragment structures built up by sp 2 carbons, as the polycyclic aromatic hydrocarbons lost aliphatic chains or ether bonds is easier to oxidation when the proportion of mixed acid and the water reached to a certain value (Ross et al 1986). They are typical fluorescent substances of carbon nanoparticle structure (Eda et al 2010).…”