Nano silica boron sulfuric acid as a dual Brønsted/Lewis acid and a heterogeneous catalyst in Baeyer–Villiger oxidation of ketones with hydrogen peroxide

Abstract

In this work, new applications of one solid acid, nano silica boron sulfuric acid (NSBSA) as a dual Bronsted/Lewis acid in Baeyer–Villiger (B–V) oxidation of ketones with hydrogen peroxide has been introduced; which, because their very small size and large surface area, can improve the capability of this heterogeneous catalyst and promote the B–V oxidation process. The synthesized nano matter was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and FT-IR. It was found that the H2O2/NSBSA system showed good efficiency in the B–V oxidation of alicyclic, aliphatic and aromatic ketones to either esters or lactones. The effects of reaction conditions, such as amount of catalyst, reaction temperature, reaction time and different solvents on the catalytic performance of NSBSA were also investigated. Notably, the process has advantages such as mild reaction conditions, simple operation and high product yield. To the best of our knowledge, the use of the H2O2/NSBSA system in B–V reactions has never been reported. It should be pointed out that H2O2, as an environmentally benign oxidant, produces water as the safest by-product and NSBSA can also be recycled and reused for several times without extremely loss of its catalytic activity.