16 documents found, page 1 of 2
Stability of clay-based catalysts in contact with water vapour
Cansado, I.P.P; Carrott, M. M. L. R.; Carrott, P.J.M.; Castilho, P.; Catrinescu, C.; Fernandes, C.; Breen, C.The search for cleaner processes is one of the major challenges in modern chemical industries. In this context clay derived materials are environmentally friendly catalysts that can be easily tailored to optimize their catalytic activity for a precise reaction of interest. Furthermore, clay-based catalysts can be easily separated, recovered and reused and their versatility, low cost, high catalytic activity and...
Porosity in ion-exchanged and acid activated clays evaluated using n-nonane pre...
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Carrott, P.J.M.; Russo, P.A.; Castilho, P.; Fernandes, C.; Catrinescu, C.; Breen, C.The applicability of the n-nonane pre-adsorption method for characterising the porosity in clays is presented. Na-SD, a Naþ-exchanged purified bentonite, and materials obtained by Al3þ-exchange and acid treatments of Na-SD and SAz-1 were used. Nitrogen adsorption isotherms, at 196 C, were determined before and after n-nonane pre-adsorption on each of the samples. In all materials, n-nonane remained adsorbed in ...
Selective methoxylation of α-pinene to α-terpinyl methyl ether over Al3+ ion-ex...
Catrinescu, C.; Fernandes, C.; Castilho, P.; Breen, C.In this study, we report the use of clay-based catalysts in the methoxylation of -pinene, for the selective synthesis of -terpinyl methyl ether, TME. The main reaction products and intermediates were identified by GC–MS. The reaction conditions (stirring rate and catalystload)that afford a kinetic regime were estab lished. SAz-1 (Cheto, Arizona, USA) source clay and a montmorillonite (SD) from Porto Santo, Made...
Selective methoxylation of limonene over ion-exchanged and acid-activated clays
Catrinescu, C.; Fernandes, C.; Castilho, P.; Breen, C.; Ribeiro Carrott, M.M.L.; Cansado, I.P.P.In this study, we report the use of clay-based catalysts in the methoxylation of limonene, for the selective synthesis of terpinyl methyl ether. Na-SAz-1, Ca-SWy-2 and Sap-Ca source clays and a montmorillonite (SD) from Porto Santo, Madeira Archipelago, Portugal were modified by (i) ion-exchange with Al, Fe, Ni and Na and (ii) acid activation, to produce catalysts with markedly different acidic and textural pro...
Catalisadores derivados de uma argila do Porto Santo: efeito da ativação ácida ...
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Russo, P.A.; Carrott, P.J.M.; Catrinescu, C.; Castilho, P.; Fernandes, C.; Breen, C.No âmbito de um projeto de investigação em curso (PTDC/CTM-CER/121295/2010), materiais derivados de argilas, de várias proveniências e submetidas a diferentes tratamentos de modificação, estão a ser usados como catalisadores em várias reações de interesse, como, por exemplo, na metoxilação do limoneno e na conversão do glicerol. Uma das possíveis vantagens, face a outros catalisadores alternativos, relaciona-se...
Adsorption and pre-adsorption for the detailed characterisation of clay catalysts
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Carrott, P.J.M.; Castilho, P.; Catrinescu, C.; Fernandes, C.; Breen, C.Ion exchange and acid activation are easy and appropriate modification treatments for obtaining versatile clay derived catalysts which can be tailored for a precise reaction of interest. Depending on the specific conditions and also on the nature of the starting clays, the alterations in the porosity and the surface chemistry that occur can be determinant for the catalytic performance, in particular for selecti...
Selective methoxylation of limonene over ion-exchanged and acid-activated clays
Castilho, P.; Catrinescu, C.; Spínola, V.; Fernandes, C.; Ribeiro Carrott, M.; Cansado, I.; Breen, C.In this work, the use of clay-based catalysts, with markedly different acidity and textural properties, in the methoxylation of limonene for the selective synthesis of -terpinyl methyl ether, is reported.
Porosity of clay catalysts for biomass conversion: a comparative study
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Castilho, P.; Carrott, P.J.M.; Catrinescu, C.; Fernandes, C.; Breen, C.A detailed description of the porosity, in particular of microporosity, was reported and allowed a clear comparison of the effects on the porosity of chemical treatments on clays from the Source Clays Repository (USA) and SD clay from Porto Santo (Portugal).
Porosity of acid activated Porto Santo bentonites assessed by n-nonane pre-adso...
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Russo, P. A.; Carrott, P.J.M.; Catrinescu, C.; Castilho, P.; Fernandes, C.; Breen, C.In previous work, we found that the materials produced by acid treatment of a bentonite collected at Serra de Dentro (Porto Santo Island, Portugal) exhibited high catalytic activity in the oxidation of limonene to p-cymene. Although a considerable increase in surface area was observed for the more active samples, a detailed description of the porosity is necessary to understand its role in the catalytic perform...
Selective methoxylation of limonene over ion-exchanged and acid-activated clays
Catrinescu, C.; Fernandes, C.; Castilho, P.; Breen, C.; Carrott, M.M.L. Ribeiro; Cansado, I.P.P.In this study, we report the use of clay-based catalysts in the methoxylation of limonene, for the selective synthesis of -terpinyl methyl ether. Na-SAz-1, Ca-SWy-2 and Sap-Ca source clays and a montmorillonite (SD) from Porto Santo,Madeira Archipelago, Portugal weremodified by (i) ion-exchange with Al, Fe, Ni and Na and (ii) acid activation, to produce catalysts with markedly different acidic and textural prop...