Synthesis of new polymer-supported multi-site phase transfer catalysts and their catalysis for the C-alkylation of 1-indanone in association with ultrasound: A kinetic study

摘要

Three different types of polymer supported multi-site phase transfer catalysts having two, four and six active sites are synthesized by simple routes. The available number of active sites in each catalyst was established based on the results derived from various microscopic and spectroscopic techniques. Similarly, the catalytic ability of each catalyst was studied by determining their pseudo-first order rate constants for C-alkylation of 1-indanone. The comparative catalytic study reveals that the k_(obs) determined under the influence of combination of ultrasound and mechanical stirring showed five and three fold increase in the activity compared to the individual effect. Similarly, the catalytic efficiency was found to be in the order: six-site >four-site >two-site >single-site irrespective of individual effect of ultrasound/mechanical stirring or both, thus confirming the availability of active sites in each catalyst. Furthermore, the detailed kinetics of C-alkylation of 1-indanone was conducted using the superior six-site PSBTTMACEMPE catalyst by varying stirring speed, [substrate], [catalyst], [NaOH], and temperature. Based on the observed kinetic results and activation energy, a suitable mechanism was proposed.