New soluble multi-site phase transfer catalysts and their catalysis for dichlorocarbene addition to citronellal assisted by ultrasound—A kinetic study

Two new soluble multi-site phase transfer catalysts (MPTCs), viz., 1,4-bis-(triethylmethylene ammonium chloride)-2,5-dimethyl benzene (BTMACD) containing di-site and 1,4-bis((3,5-bis(triethylmethyleneammonium chloride)phenoxy)methyl)benzene (TEMACPB) containing tetra-site were prepared and proved by FT-IR, 1H NMR, 13C NMR, mass and elemental analysis. The enhancement of CN peak intensity at 1179 cm−1 noticed in FT-IR, the agreement of m/z values, viz., 405 and 888 for di-site and tetra-site respectively with their theoretical values and the percentage of C, H, N elements noticed in elemental analysis has strongly supported the presence of di-site and tetra-site in the BTMACD and TEMACPB catalysts. Further, the presence of number of active-sites in each catalyst was again confirmed by determining their pseudo-first order rate constant for dichlorocarbene addition to citronellal in the presence of ultrasonic irradiation/mechanical stirring. The comparative study reveals that the kobs determined with the combination of ultrasound and mechanical stirring has shown more activity (3 fold) than with their individual effect. Further, the detailed kinetic study performed with superior tetra-site MPTC (TEMACPB) reveals that the kobs are dependent with the stirring speed, [substrate], [catalyst], [NaOH] and temperature. Based on the kinetic results, thermodynamic parameters are evaluated and an interfacial mechanism is proposed.

Two new soluble multi-site phase transfer catalysts (MPTCs), viz., 1,4-bis-(triethylmethylene ammonium chloride)-2,5-dimethyl benzene (BTMACD) containing di-site and 1,4-bis((3,5-bis(triethylmethyleneammonium chloride)phenoxy)methyl)benzene (TEMACPB) containing tetra-site were prepared and proved by FT-IR, 1H NMR, 13C NMR, mass, and elemental analyses. Further, the presence of number active-sites in each catalyst was again confirmed by determining their pseudo-first order rate constant for dichlorocarbene addition to citronellal in the presence of ultrasonic irradiation/mechanical stirring. The comparative study reveals that the kobs determined with the combination of ultrasound and mechanical stirring has shown more activity (3 fold) than with their individual effect. Further, the detailed kinetic study performed with superior tetra-site MPTC (TEMACPB) reveals that the kobs are dependent with the stirring speed, [substrate], [catalyst], [NaOH] and temperature. Based on the kinetic results, thermodynamic parameters are evaluated and an interfacial mechanism was proposed.Figure optionsDownload high-quality image (61 K)Download as PowerPoint slideHighlights
► Two new soluble multi-site phase transfer catalysts (MPTCs) prepared.
► Catalytic activity was examined by dichlorocarbene addition to citronellal reaction.
► Comparative study reveals combination of US and MS is 3 fold more active.
► Detailed kinetic study performed with superior tetra-site MPTC (TEMACPB).
► Based on the kinetic results an interfacial mechanism was proposed.