Smectite clay KSF as effective catalyst for oxidation of m-tyrosol with H 2 O 2 to hydroxytyrosol

A successful procedure to demonstrate the ability to produce high-added value phenolic hydroxytyrosol by oxidation of m-tyrosol was developed, using clay KSF/H 2 O with peroxide hydrogen to afford excellent yields (more than 60%). Three different operating parameters, including m-tyrosol, H 2 O 2 concentration and amount of catalyst were performed using an experimental design methodology “Box–Behnken” for hydroxytyrosol production. All derivative compounds in reaction mixture during reaction time were identified using mass spectrometry. Hydroxytyrosol 3,4-dihydroxystyrene; 3-hydroxyphenyl acetic acid and 2.5-dihydroxyphenylethanol were the major compounds. By means of 2,2-diphenyl-1-picrylhydrazyl DPPH method, the antioxidant activity was realized, indicating that the strongest antiradical activity (IC 50% = 21.57 mg/mL) was detected when the concentration of hydroxytyrosol is higher. The developed synthesis, investigated for the first time, is operationally simple and could find application for industrial purposes. © 2019, Akadémiai Kiadó, Budapest, Hungary.