tailieunhanh - Oxidation of benzyl alcohol to benzaldehyde over MnOx/sepiolite catalysts

MnOx/sepiolite catalysts were synthesized by precipitation method accompanied by the calcination at 4100C. The prepated solids have been characterized by XRD, SEM, TPR-H2. MnOx particles were deposited on the surface of the sepiolite fibers and act as active sites for the oxidation of benzyl alcohol using tert-butyl hydroperoxide (TBHP) as an oxidizing agent. The catalysts showed a good conversion of benzyl alcohol to benzaldehyde at 60 oC. The influence of the reaction time and reaction temperature was considered. | Vietnam Journal of Chemistry, International Edition, 55(6): 729-733, 2017 DOI: Oxidation of benzyl alcohol to benzaldehyde over MnOx/sepiolite catalysts Nguyen Thi Nhu1,2, Quach Toan Anh1, Nguyen Tien Thao1* 1 Faculty of Chemistry, VNU University of Science, Vietnam National University, Hanoi 2 Institute of Environment, Vietnam Maritime University Received 12 June 2017; Accepted for publication 29 December 2017 Abstract MnOx/sepiolite catalysts were synthesized by precipitation method accompanied by the calcination at 4100C. The prepated solids have been characterized by XRD, SEM, TPR-H2. MnOx particles were deposited on the surface of the sepiolite fibers and act as active sites for the oxidation of benzyl alcohol using tert-butyl hydroperoxide (TBHP) as an oxidizing agent. The catalysts showed a good conversion of benzyl alcohol to benzaldehyde at 60 oC. The influence of the reaction time and reaction temperature was considered. Keywords. MnOx/sepiolite, oxidation, benzyl alcohol conversion, TBHP, benzaldehyde. 1. INTRODUCTION The selective oxidation of benzyl alcohol to benzaldehyde is an important reaction in the pharmaceutical, dyestuff, agrochemical and perfume industries. For a long time ago, benzaldehyde was produced by hydrolyzing benzyl chloride or by oxidizing toluene 0. Product mixture from these reactions has low selectivity to desired product or contaminates chlorine causing drawbacks for environmental influence 2. An other way is to use homogeneous catalysts as CrO3/H+ or a complex of transition metal in oxidation of benzyl alcohol that meet difficulties as the separation and recycling catalysts. Therefore, development of heterogeneous catalysts for the selective oxidation of benzyl alcohol became more attractive for many chemists. Recently, a vast number of supported noble-metal catalysts (such as Pt, Pd, Au) have exhibited very low selective oxidation of alkyl benzene at mild conditions 2. However, these .