Ionone synthesis on solid acid catalysts

V.K. DÍEZ; C.R. APESTEGUÍA; I. DI COSIMO

San Francisco, California, USA

Congreso; 21st Meeting of the North American Catalysis Society; 2009

Figure 2: Effect of reaction time (T=383 K, HPAS-59) Ionones (a, b, g) are valuable chemicals. The b-ionone is used in the synthesis of vitamin A, whereas a- and g-ionone are employed in fragrances. Ionones are commercially produced from citral via a two-step process that involves liquid catalysts. In particular, the second step, the cyclization of pseudoionone (PS), is promoted by sulfuric acid. Few works report the use of solid acids for this step but yields (49 %) [1] are still lower than those of the homogeneous reaction (70-90 %). In this work we postulate two silica-supported acid catalysts to selectively convert PS into ionones: heteropolyacid (HPA) and triflic acid (TFA). Our goal was to investigate the effect of the acid species and reaction conditions on the ionone synthesis and on the ionone isomer distribution.