INVESTIGADORES
ROMANELLI Gustavo Pablo
artículos
Título:
Tungstophosphoric acid/zirconia composites prepared by the solgel method:
Autor/es:
T. RIVERA; A. SOSA; G. ROMANELLI; M. BLANCO; L. PIZZIO
Revista:
APPLIED CATALYSIS A-GENERAL
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 443 p. 207 - 213
ISSN:
0926-860X
Resumen:
Samples of zirconia modified with different contents of tungstophosphoric acid (TPA) were synthesized
from zirconium propoxide via solgel reactions using polyethylene glycol as template and were characterized
by different physicochemical techniques (BET, XRD, FT-IR, and 31P MAS-NMR). The SBET of the
solids decreases and the microporosity increases with the increase of the TPA content. According to FT-IR
and 31P MAS-NMR studies, the main species present in the samples is [PW12O40]3− anion, which was partially
transformed into [P2W21O71]6− and [PW11O39]7− anions during the synthesis and drying steps. The
XRD patterns of the modified samples exhibit neither the characteristic peaks of TPA nor those attributed
to its decomposition products.
Aryl-14H-dibenzo[a,j]xanthenes have been synthesized by a one-pot condensation of 2-naphthol and
aryl aldehydes, catalyzed by tungstophosphoric acid/zirconia composites in a solvent-free medium using
conventional heating. The present approach offers the advantages of clean reaction, simple methodology,
short reaction time, and high yield. The reaction work-up is very simple and the catalyst can be
easily separated from the reaction mixture and reused several times in subsequent reactions without
appreciable loss of the catalytic activity.