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Sambeth J.E.,Research Center sarrollo En Ciencias Aplicadas Dr Jorge nco Cindeca | Romanelli G.,Research Center sarrollo En Ciencias Aplicadas Dr Jorge nco Cindeca | Romanelli G.,National University of La Plata | Autino J.C.,National University of La Plata | And 2 more authors.
Applied Catalysis A: General | Year: 2010

The aim of the present work is to predict theoretically the nature of the mechanism of catalytic behaviour, pseudoliquid or surface-type, of Wells-Dawson solid acid (WDA). For this purpose, we took into account the dipolar moment of the substrates and the presence of H5O2+ species in their structure, considering both theoretical and experimental results. In the present paper we studied experimentally the deprotection reaction of aldehydes from 1,1-diacetates. These theoretical and experimental results together with our previous works indicate that the catalytic behaviour of WDA is a function of the dipolar moment of organic molecules and the presence of H5O2+ species. The pseudoliquid or surface-type behaviour depends on the physicochemical properties of the organic structure and its possibility of interaction with H5O2+. © 2010 Elsevier B.V. All rights reserved. Source


Ruiz D.M.,National University of La Plata | Romanelli G.P.,National University of La Plata | Romanelli G.P.,Research Center sarrollo En Ciencias Aplicadas Dr Jorge nco Cindeca | Vazquez P.G.,Research Center sarrollo En Ciencias Aplicadas Dr Jorge nco Cindeca | Autino J.C.,National University of La Plata
Applied Catalysis A: General | Year: 2010

In the present work a series of eco-friendly Preyssler solid acids and their salts H14[NaP5W29MoO110] (PW), H14[NaP5W30O110] (PWMo), K12.5Na1.5[NaP5W30O110]·15H2O (PWK), K12.5Na1.5[NaP5W29MoO110]·15H2O (PWMoK) and 10% silica-supported H14[NaP5W29MoO110] (PWSiO2), and H14[NaP5W30O110] (PWMoSiO2) have been used as catalysts for the direct esterification of cinnamic acids with phenols or 2-(N-phthalimidoethanol). Effects of the reaction conditions were studied, including temperature, reaction time, and type and amount of catalyst. These solids were characterized by several techniques, such as diffuse reflectance spectroscopy, Fourier transformed infrared spectroscopy, optical and scanning electron microcopies, and X-ray diffraction, among others. The most adequate catalyst for performing the title reaction was H14[NaP5W30O110] (PWMo). The catalyst was applied for the synthesis of various substituted cinnamates, giving very good yields. © 2009 Elsevier B.V. All rights reserved. Source

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