Propargylation of indene-1,3-dione under a new phase-transfer catalyst combined with ultrasonication – A kinetic study

• A new phase-transfer catalyst was used for propargylation of indene-1,3-dione.
• Effect of ultrasound was studied in this reaction.
• Different frequency of ultrasound irradiation was tested.
• A suitable reaction mechanism was proposed for this reaction.

In the present study, kinetics of synthesis of 2,2-di(prop-2-ynyl)-1H-indene-1,3(2H)-dione was successfully carried out by propargylation of indene-1,3-dione with propargyl bromide using aqueous potassium hydroxide and catalyzed by a newly synthesized phase-transfer catalyst viz., N-benzyl-N-ethyl-N-isopropylpropan-2-ammonium bromide, PTC under ultrasonic (40 kHz, 300 W) assisted organic solvent condition. The pseudo first-order kinetic equation was applied to describe the overall reaction. Under ultrasound irradiation (40 kHz, 300 W) in a batch reactor, it shows that the overall reaction rate can be greatly enhanced with ultrasound irradiation than without ultrasound.