On the mechanism of alcoholysis of allylic and benzylic alcohols and of epoxides in the presence of ceric ammonium nitrate

Lewis Acids as Catalysts in Oxidation Reactions: From Homogeneous to Heterogeneous Systems

“…It is believed that these protons are responsible of the cerium ammonium nitrate-catalyzed methanolysis of allylic and benzylic alcohols. 166 This reaction can also be catalyzed equally well by other Lewis acids, thus, reinforcing the assumption that cerium ions intervene as Lewis acids in this alcoholysis. 166 Benzyl esters are formed catalytically at moderate temperatures from alkyl benzenes using sodium bromate as oxidant and cerium ammonium nitrate as catalyst in a carboxylic acid as solvent.…”

“…166 This reaction can also be catalyzed equally well by other Lewis acids, thus, reinforcing the assumption that cerium ions intervene as Lewis acids in this alcoholysis. 166 Benzyl esters are formed catalytically at moderate temperatures from alkyl benzenes using sodium bromate as oxidant and cerium ammonium nitrate as catalyst in a carboxylic acid as solvent. 167 Thus, toluene gives benzyl acetate in acetic acid.…”

Well-defined epoxide-containing styrenic polymers and their functionalization with alcohols

“…Heterogeneous acidic catalysts that have been successfully employed for this purpose include sulfonated polymers (Amberlyst‐15 and Nafion‐H), neutral alumina, mesoporous aluminosilicate, organotin phosphate condensates (OPCs), and Fe 3+ ‐montmorillonite, but it is unlikely that they could achieve sufficient interaction with the pendant functionalities of polymers to efficiently promote functionalization. Soluble compounds or complexes of main group metals, transition metals, and lanthanides are well‐known for their Lewis acidity and have been investigated specifically for their ability to catalyze the alcoholysis of epoxides. The catalytic activities of non‐metallic Lewis acids like BF 3 , CBr 4 , hydrazine sulphate, molecular iodine, iminium triflate, and trimethylsilyl triflate, as well as compounds able to participate in single‐electron reactions like 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone, tetracyanoethylene, ceric ammonium nitrate, N ‐methylpyrrolidine‐2‐one hydrotribromide, and 1‐benzyl‐2,4,6‐triphenylpyridinium tetrafluoroborate, have also been explored.…”

“…Soluble compounds or complexes of main group metals, transition metals, and lanthanides are well‐known for their Lewis acidity and have been investigated specifically for their ability to catalyze the alcoholysis of epoxides. The catalytic activities of non‐metallic Lewis acids like BF 3 , CBr 4 , hydrazine sulphate, molecular iodine, iminium triflate, and trimethylsilyl triflate, as well as compounds able to participate in single‐electron reactions like 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone, tetracyanoethylene, ceric ammonium nitrate, N ‐methylpyrrolidine‐2‐one hydrotribromide, and 1‐benzyl‐2,4,6‐triphenylpyridinium tetrafluoroborate, have also been explored. Many of these compounds are labeled as “mild” and “highly‐efficient” catalysts that are capable of rendering desired products in excellent yields (>90%) at room temperature within minutes to a few hours, but a close examination of the literature reveals that these claims often only hold true when the nucleophiles are short‐chain primary alcohols (usually methanol) and are used in large excess (10–100 eq.…”

Environmentally friendly sol - gel-based anticorrosive coatings on aluminum alloy 2024

“…The Ce 4+ is a strong oxidizing agent that can easily oxidize an alcohol to the correspondent aldehyde. In this sense, the redox process between Ce 4+ and methanol has been previously demonstrated 17 , and the oxidation product, formaldehyde, has been identified by trapping techniques 18 . The sol precursors prepared in our study were stirred by sonication in ultrasound (Sonicator Ultrasonic Processor XL) equipment for half an hour previous to their deposition on alloy samples, to avoid the complete reduction of cerium.…”