tailieunhanh - Catalytic activity of Cr2O3/sepiolite in the oxidation of benzyl alcohol

Cr2O3/sepiolite samples with different loadings have been synthesized from corresponding nitrate salts at constant pH conditions and characterized by several physical methods including X-ray diffraction, TEM, nitrogen physisorption, and TGA, etc. The asprepared materials have large surface area, high distribution of Cr2O3 nanoxides on the nanofibrous sepiolite. The prepared solids were used as heterogeneous catalysts for the oxidation of benzyl alcohol with t-BuOOH. Chromium oxides were found to be active sites for the liquid oxidation of benzyl alcohol to aldehyde. The catalytic activity varied with reaction time and temperature. The appropriate temperature is about 60-70 oC with conversion of 40-60 % and benzaldehyde selectivity of 90 % | Vietnam Journal of Science and Technology 56 (3) (2018) 295-302 DOI: CATALYTIC ACTIVITY OF Cr2O3/SEPIOLITE IN THE OXIDATION OF BENZYL ALCOHOL Nguyen Tien Thao1, *, Nguyen Thi Nhu1, 2, Ngo Thi Thuan1 1 Faculty of Chemistry, VNU University of Science, Vietnam National University, 19 Le Thanh Tong Str., Hoan Kiem, Ha Noi 2 Institute of Environment, Vietnam Maritime University, 484 Lạch Tray Str. Le Chan, Hai Phong * Email: ntthao@, nguyentienthao@ Received: 4 December 2017; Accepted for publication: 10 April 2018 Abstract. Cr2O3/sepiolite samples with different loadings have been synthesized from corresponding nitrate salts at constant pH conditions and characterized by several physical methods including X-ray diffraction, TEM, nitrogen physisorption, and TGA, etc. The asprepared materials have large surface area, high distribution of Cr2O3 nanoxides on the nanofibrous sepiolite. The prepared solids were used as heterogeneous catalysts for the oxidation of benzyl alcohol with t-BuOOH. Chromium oxides were found to be active sites for the liquid oxidation of benzyl alcohol to aldehyde. The catalytic activity varied with reaction time and temperature. The appropriate temperature is about 60-70 oC with conversion of 40-60 % and benzaldehyde selectivity of 90 %. Keywords: benzyl alcohol, sepiolite, fiber, benzaldehyde, Cr2O3. Classification numbers: ; ; . 1. INTRODUCTION The oxidation of alcoholic compounds to carbonyls was known as an important reaction in organic synthesis due to its oxidation products are widely applied in the synthesis of fine chemicals [1, 2]. Conventionally, large amounts of heavy transition metal salts, metal oxides, and peracids are used in the oxidation reaction of organic compounds. As a consequence, these methods always create a huge amount of heavy metal wastes that further violate with environmental regulations [2, 3]. This makes researchers seek alternative procedures .

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