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

•NaOH-cationic micellar systems were demonstrated for selective cross aldol reaction.•Highest jasminaldehyde selectivity (∼90%) in cross aldol reaction of benzaldehyde and n-heptanal at equimolar ratio.•Selective and fast synthesis in aqueous NaOH-micellar solution at room temperature.•Effect of surfactant concentration on conversion and selectivity of cross aldol product.•Reuse of aqueous NaOH-micellar solution.

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: 200 mM) aqueous solution resulted to highest conversion of n-heptanal (99%) with 90% selectivity to jasminaldehyde within 4 h. The reusability of NaOH-CTAB system was examined for five reaction cycles.

Graphical abstractThe NaOH-cationic micellar system was employed for selective cross aldol condensation of benzaldehyde with n-heptanal in equimolar amount to synthesize jasminaldehyde (90%).Figure optionsDownload full-size imageDownload high-quality image (169 K)Download as PowerPoint slide