2-methoxynaphthalene acylation using aluminum or copper salts of tungstophosphoric and tungstosilicic acids as catalysts

LETICIA MÉNDEZ; ROSARIO TORVISO; LUIS PIZZIO; MIRTA BLANCO

Saragoza España

Congreso; 9th Congress on Catalysis and Fine Chemicals (CAFC9); 2010

the results obtained in the acylation in liquid phase of 2-methoxynaphthalene (2MN) with acetic anhydride (AA), using Al3+ or Cu2+ salts of tungstophosphoric (TPA) and tungstosilicic (TSA) acids are presented.  The Keggin structure of the tungstophophoric and tungstosilicic is present intact in the synthesized salts. The salts of TPA are thermally more stable than those of TSA. On the other hand, they present very strong acid sites, being higher the acid strength of the Al3+ salts. The nature of the solvent used to carry out the reaction has an important influence on the conversion, being better to use weakly donor ones. The synthesized salts are an excellent alternative respect to the classic catalysts to be used in the studied reaction performed without solvent, because they led to very high conversion, with 1-acetyl-2-methoxynaphthalene (1-A-2MN) as main product. The best yields were obtained with the aluminum salts, in accordance to their higher acidity.