Original scientific paper

Amorphization Effects on the Basic Sites of Nanometric Magnesium Oxide

Neftalí Lenin Villarreal Carreño ; Instituto de Química, DQAI, Universidade Federal de Pelotas, Capão do Leão, RS, Brazil
David Keyson ; Departamento de Química, Universidade Federal de São Carlos, São Carlos – SP, Brasil
Marcia Tsuyama Escote ; Departamento de Química, Universidade Federal de São Carlos, São Carlos – SP, Brasil
Edson Roberto Leite ; Departamento de Química, Universidade Federal de São Carlos, São Carlos – SP, Brasil
Elson Longo ; Departamento de Química, Universidade Federal de São Carlos, São Carlos – SP, Brasil
Humberto Vieira Fajardo ; Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis – SC, Brasil
Luiz Fernando Dias Probst ; Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis – SC, Brasil
Antoninho Valentini ; Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará, Fortaleza – CE, Brasil
Miryam Rincón Joya ; Departamento de Física, Universidade Federal de São Carlos, São Carlos – SP, Brasil
Paulo Sergio Pizani ; Departamento de Física, Universidade Federal de São Carlos, São Carlos – SP, Brasil

Abstract

The paper reports the catalytic action of the basic sites of nanocrystalline particles of rare
earth-doped magnesium oxide in the aldolization reaction between acetone and methanol leading
to the C–C bond formation of an a,b-unsaturated compound (methyl vinyl ketone), also forming
methyl ethyl ketone and isopropyl alcohol. Undoped and doped MgO samples were prepared by
high-energy mechanical milling of commercial Mg, Y and Ce oxide powders. Catalytic activity
and surface basicity of these compounds were strongly influenced by doping and the time of mechanical
milling (amorphization process). Such milling leads to the formation of nanocrystalline
materials. Influence of mechanical processing of these compounds was investigated by means of
N2 adsorption (BET), X-ray diffraction (XRD), TEM, CO2 chemisorption and room temperature
photoluminescence emission. Strong changes of polar groups such as hydroxyl groups on the
surface of the solid were directly related to the photoluminescence emission observed.

Keywords

magnesium oxide; amorphization; catalysts; photoluminescence; aldol condensation

Hrčak ID:

31129

URI

https://hrcak.srce.hr/31129

Publication date:

15.11.2008.

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