Investigação

CARACTERIZAÇÃO GEOMECÂNICA DE MATERIAIS ROCHOSOS, DE ORIGEM VULCÂNICA, DA ILHA DA MADEIRA

Este artigo tem como objectivo contribuir para a caracterização geomecânica de materiais rochosos da Ilha da Madeira. Para tal procedeu-se ao ensaio de algumas amostras de diferentes litologias, pertencentes a diferentes (...)

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PORTO SANTO CLAYS AS ENVIRONMENTALLY FRIENDLY CATALYSTS FOR THE CONVERSION OF RENEWABLE TERPENE FEEDSTOCKS. LIMONENE AROMATIZATION TO P-CYMENE

Cezar Catrinescu, Cesar Fernandes, Paula Castilho, Christopher Breen, Manuela Carrott

A bentonite collected at Serra de Dentro, Porto Santo Island, Portugal was selected as the starting material for the preparation of ion-exchanged clay catalysts. The pristine clay was characterized in terms of chemical composition (XRF), structure (XRD an FTIR spectroscopy), textural properties (nitrogen adsorption), acidity (TG of cyclohexylamine saturated samples) and catalytic activity (limonene conversion). Results show that clays exchanged with acidic cations (Al3+, Ni2+) are very active in limonene conversion, but the selectivity for p-cymene is low ( 15 %). In contrast, over the Na+-exchanged form, the reaction is slower but the selectivity to p-cymene is significantly increased (around 35 %). The inherent dehydrogenation activity of the SD clay could be considered responsible for this process.

Environmental Engineering and Management Journal, September 2006, Vol.5, No.3, 275-284
http://omicron.ch.tuiasi.ro/EEMJ/