Synthesis of mesoporous MgO catalyst templated by a PDMS–PEO comb-like copolymer for biodiesel production

Abstract

Mesoporous MgO catalyst was synthesized from Mg(NO3)2 via a sol-gel process by templating an amphiphilic comb-like copolymer, poly(dimethylsiloxane–ethylene oxide) (PDMS–PEO). The copolymer morphology was worm-like and microphase-separated in a good solvent but micellar in a selective solvent, such as toluene and water. By templating micelles of PDMS–PEO copolymer, mesoporous MgO with a high surface area was generated after calcination at 500°C, as confirmed by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. Mesoporous MgO was used as a heterogeneous solid catalyst to produce biodiesel from canola oil. PDMS–PEO templated MgO (t-MgO) converted biodiesel more efficiently (~98.2% methyl ester content) than non-templated MgO (nt-MgO, 82.8%). The number and strength of basic sites of MgO catalyst were also investigated using CO2-temperature-programmed desorption (CO2-TPD) analysis.