Enhancing the accessibility to basic sites of as-synthesized silicas applied in catalytic transesterification

Autor(es)

Zapelini, Iago W. ^[1] ; Silva, Laura L. ^[1] ; Oliveira, Cristiano L. P. ^[2] ; Cardoso, Dilson ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Chem Engn Dept, Catalysis Lab, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Inst Phys, Rua Matao 1371, BR-05508090 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Applied Surface Science; v. 507, MAR 30 2020.
• Citações Web of Science: 0

Resumo

Heterogeneous catalysis for biodiesel production is a current challenge due to the low activity of solid catalysts, especially caused by diffusional resistances. Hybrid silicas, containing = SiO(-)CTA(+) provide high conversions in the transesterification of oils and model molecules, but this activity is limited to the external surface area. The generation of surface roughness in the silica particles can increase the external area of the catalysts and expose the catalytic sites. Rough silicas containing cetyltrimethylammonium (CTA(+)) surfactant were prepared using different {[}CTABr]/{[}TEOS] molar ratios in a biphasic system formed by diethyl ether and water. The resulting solids were characterized by FTIR, O1s XPS, TG, SEM, and TEM. These materials were applied as basic catalysts in a model transesterification reaction representing the formation of biodiesel. Increasing the CTA(+) content in the synthesis resulted in higher turnover frequencies, due to the smaller particle size and greater surface roughness of the material, which enhanced the accessibility of reagents to the basic siloxy sites. (AU)

• Processo FAPESP: 16/21033-2 - Preparação e modificação de sílicas híbridas esféricas para transesterificação catalítica
• Beneficiário: Iago William Zapelini
• Modalidade de apoio: Bolsas no Brasil - Mestrado