Kinetics of phase-transfer-catalyzed oxidations ofp-substituted benzyl alcohols with aqueous hypochlorite

Abstract

A series of p-substituted benzyl alcohols have been oxidized to their corresponding aldehydes using aqueous hypochlorite and phase-transfer catalyst (PTC) conditions. The reaction constant, 9, has been determined to be +1.03. Possible mechanisms are suggested.

Synthesis and structural characterization of CO2-soluble oxidizers [Bu4N]BrO3 and [Bu4N]ClO3 and their dissolution in cosolvent-modified CO2 for reservoir applications

“…35 For example, tetrabutylammonium hypochlorite can be generated in situ and transferred to an organic phase where benzyl alcohol is oxidized to aldehyde. [36][37][38] Tetrabutylammonium cation has also been paired with bromite 39 Tetrabutylammonium bromate monohydrate crystallizes as colorless block-like crystals from an aqueous solution. The asymmetric unit consists solely of the ammonium cation, bromate anion and water of crystallization.…”

Hypochlorite-Induced Ipso-Substitution Reactions of Aromatic Alcohols and Related Compounds

“…13 Significantly, this substituent has been found to have a deactivating effect on the OCl -/PTC oxidation of benzyl alcohols. 14 Reaction of 1a with aqueous NaOCl at pH 8-9, PTC and dichloromethane resulted in ca. 30-40% yield of 4-methoxychlorobenzene [4-chloroanisole (2a)] through ipso substitution in addition to 4methoxybenzaldehyde [anisaldehyde (3)], the expected oxidation product.…”

Competing Reactions of Secondary Alcohols with Sodium Hypochlorite Promoted by Phase-Transfer Catalysis

“…Under basic conditions, the utilization of a phase transfer catalyst (PTC) such as tetra- n -butylammonium hydrogen sulfate (TBAHS) facilitates secondary alcohol to ketone transformation in two phase systems, with ethyl acetate exhibiting better results than dichloromethane as the organic phase . Kinetic studies, conducted in air, of substituted 1-phenylethanols as well as benzyl alcohols have shown that such oxidations are facilitated by electron withdrawing substituents and point toward an ionic reaction mechanism.…”