Selectivity in the Oxidation of Aliphatic Ketones by thallic sulphate in aqueous medium

Abstract

AbstractThe effects of temperature, structure and sulphuric acid concentration on the selectivity of the oxidation of aliphatic ketones (R1COR2) (1a–g) by thallic sulphate have been investigated. With increasing temperature the quantity of internal α‐hydroxyketone (3a–d) decreases and the quantity of 1‐hydroxyketone (2a–d) increases in the oxidation of methyl alkyl ketones (R2>CH3) (1a–d). The same concerns to the oxidation products of hexan‐3‐one (1e): 2‐hydroxy‐hexan‐3‐one (2e) and 4‐hydroxy‐hexan‐3‐one (3e), respectively. “The inverse selectivity temperature” (IST) for oxidation of linear methyl alkyl ketones (1a–c) and hexan‐3‐one (1e) has been found. With the use of the linear free‐energy relationship it has been found that the selectivity of the reaction decreases with increasing the polar and steric effects of substituents R1, R2. With increasing the sulphuric acid concentration the selectivity of the oxidation of methyl alkyl ketones (1a, 1d) increases.