“Base-acid mechanism for the citral/acetone reaction on MgyAlOx oxides”

VERÓNICA K. DÍEZ; J. ISABEL DI COSIMO; CARLOS R. APESTEGUÍA

Ancient Harvor, Genova, (Italy).

Congreso; 6th Congress on Catalysis by Acids and Bases; 2009

The  liquidphase  aldol  condensation  of  citral  with  acetone  (DMK)  is catalyzed  by  diluted  bases  and  forms  selectively  pseudoionones  (PS), but the process entails concerns  related  to  toxicity, corrosion, and disposal of spent  base  materials.  New  industrial  strategies  for  PS  synthesis  demand then  the  replacement  of  liquid  bases  by  solid  catalysts.  The  citral/DMK reaction  has  been  studied  on  MgAl  mixed  oxides  (MgyAlOx),  but knowledge  regarding  the  role  played  by  the  MgyAlOx  chemical composition  to  fulfill  the  requirements  of  acid/base  site  density  and strength for promoting  the selective PS formation at high rates, is lacking. The optimum MgyAlOx composition should improve the citral/DMK crossaldol condensation rate at expenses of the DMK self condensation reaction. Here, we have carried out a detailed  study of  the citral/DMK  reaction on MgO,  Al2O3,  and  MgyAlOx  with  Mg/Al  molar  ratios  of  0.11-3.  The structural, textural and acid/base properties of the samples were determined by using a variety of experimental techniques and then correlated with the catalyst performance for citral/DMK reaction.