Impregnação do ácido 12-fosfotúngstico em sílica - parte I: determinação de parâmetros de impregnação, caracterização e avaliação da atividade catalítica

Scroccaro, Karine Isabel; Tanobe, Valcineide Oliveira de Andrade; Côcco, Lílian Cristina; Yamamoto, Carlos Itsuo

doi:10.1590/s0100-40422012000700011

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(1 citation statement)

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“…This behavior of H 3 PW supported material is in agreement with others that have detected very low leaching under adequate preparation conditions. 59,60 To verify that the catalysis was truly heterogeneous, the optimized esterification reaction was repeated three times. The 30 wt.% H 3 PW/SiO 2 -Al 2 O 3 catalyst was recovered by centrifugation, washed with ethanol, dried in an oven at 100 °C and calcined at 200 °C before reuse.…”

Section: Resultsmentioning

confidence: 99%

Acidity and Characterization of 12-Tungstophosphoric Acid Supported on Silica-Alumina

Mattos¹,

Carvalho²,

Freitas³

et al. 2016

Journal of the Brazilian Chemical Society

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This work deals with preparation and characterization of H 3 PW 12 O 40 (H 3 PW) supported on silica-alumina. Impregnation of H 3 PW (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.% H 3 PW/SiO 2 -Al 2 O 3 had the highest activity under the conditions: catalyst calcination at 300 °C, temperature of 100 °C, 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 °C).

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Section: Resultsmentioning

confidence: 99%