A novel approach for selective cross aldol condensation using reusable NaOH-cationic micellar systems

Abstract

The efficiency of NaOH-cationic micellar systems was demonstrated for selective cross aldol condensation of benzaldehyde with n-heptanal (as model reaction, which involves cross and self condensation reactions) in equimolar amount to synthesize jasminaldehyde (cross product) with high selectivity. In comparison of biphasic reactions in NaOH aqueous solution (in absence of surfactant), the aldol reactions in NaOH-micellar solution were faster and selective to cross product without consumption of NaOH. The reaction rate and jasminaldehyde selectivity was observed to be influenced by surfactant concentration and reaction temperature. The equimolar reaction of both aldehydes in NaOH-cetyltrimethyl ammonium bromide (CTAB: 200mM) aqueous solution resulted to highest conversion of n-heptanal (99%) with 90% selectivity to jasminaldehyde within 4h. The reusability of NaOH-CTAB system was examined for five reaction cycles.