CINDECA   05422
CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
artículos
Título:
Borated Zirconia modified with ammoniummetatungstate as catalyst in alcohol acetylation
Autor/es:
LILIAN OSIGLIO; A. G. SATHICQ; G. ROMANELLI; MIRTA N. BLANCO
Revista:
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2012 vol. 359 p. 97 - 97
ISSN:
1381-1169
Resumen:
Samples of tungsten-modified borated zirconia were prepared to be used as catalyst in2-phenoxyethano acetylation.  The  borated  zirconias  were  obtained  by  impregnation  of  two  zirconias  (S2  and  S4)  obtained by the micellar method using different zirconium precursor concentrations with boric acid solution con-taining  0.3  moles  B/dm3.  These  solids  and  the  parent  zirconias  were  impregnated  with  two  concentration levels of ammonium metatungstate solutions (0.11 and 0.22 moles W/dm3). The solids containing boron mainly  have  amorphous  characteristics  and  strong  acidity,  while  those  that  contain  only  tungsten  showedstronger  acidity  and  evidence  of  the  presence  of  a  crystalline  phase.  The  specific  surface  area  and  the pore  volume  slightly  decreased  in  the  solids  obtained  by  adding  tungsten  to  borated  zirconia,  and  more markedly in those that contain only tungsten, and the mean pore size increased with respect to theparent  support.  It  was  observed  that  in  the  2-phenoxyethanol  acetylation  using  acetic  acid  as  acylating agent  and  tungsten-modified  borated  zirconia  as  catalyst,  the  yield  to  acetylated  product  was  high  and it  is  correlated  with  the  acid  strength  of  the  catalysts.  In  turn,  the  solids  that  contain  only  tungsten  havea  correlation  with  the  acidity,  but  lead  to  low  yield  values  due  to  a  poorer  dispersion  of  the  tungsten species.  The  best  yield  was  obtained  with  the  catalyst  prepared  with  the  borated  S4  zirconia  containing 15%  g  B2O3/100  g  support  and  12.5%  g  W/100  g  support.  Using  this  catalyst  and  the  same  reaction  condi-tions, the acetylation of different alcohols and phenols was studied, the reactivity order being as follows primary  alcohols  > secondary  alcohols  >  phenols.
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