Título:	Acidity and characterization of 12-Tungstophosphoric acid supported on Silica-alumina
Autor(es):	Mattos, Flávia Cardoso Genaro de Carvalho, Eduardo N. C. B. de Freitas, Elon F. de Paiva, Mateus F. Ghesti, Grace Ferreira Macedo, Julio Lemos de Dias, Sílvia Cláudia Loureiro Dias, José Alves
Assunto:	Sílica-alumina Álcool Esterificação
Data de publicação:	Fev-2017
Editora:	Sociedade Brasileira de Química
Referência:	MATTOS, Flávia C. G. de et al. Acidity and characterization of 12-Tungstophosphoric acid supported on Silica-alumina. Journal of the Brazilian Chemical Society, São Paulo, v. 28, n. 2, p. 336-347, fev. 2017. Disponível em: <http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532017000200336&lng=en&nrm=iso>. Acesso em: 7 fev. 2018. doi: http://dx.doi.org/10.5935/0103-5053.20160183.
Abstract:	This work deals with preparation and characterization of H3PW12O40 (H3PW) supported on silica-alumina. Impregnation of H3PW (15, 20, 30 and 40 wt.%) on commercial silica-alumina support in acidic aqueous solution is effective for preparing this catalyst keeping its Keggin structure, according to different methods of characterization. The catalysts were tested in a model reaction of acetic acid with ethanol and 30 wt.% H3PW/SiO2-Al2O3 had the highest activity under the conditions: catalyst calcination at 300 ºC, temperature of 100 ºC, acetic acid:ethanol molar ratio of 2:1 and catalyst:acetic acid mass ratio of 10 wt.%. The reaction yield was 79 and 100% selectivity for ethyl acetate over three reutilizations, for reaction time of 2 h. The calculated total acid site distribution was 0.299 mmol g-1 (97% of the theoretical probed by pyridine), and most of these (0.236 mmol g-1) were Brønsted weak-medium strength (pyridine desorption between 300 and 500 ºC).
Unidade Acadêmica:	Instituto de Química (IQ)
Licença:	Journal of the Brazilian Chemical Society - This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0). Fonte: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532017000200336&lng=en&nrm=iso. Acesso em: 7 fev. 2018.
DOI:	http://dx.doi.org/10.5935/0103-5053.20160183
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