Catalytic activity of novel soluble multi-site phase transfer catalyst in dichlorocarbene addition to α-pinene

A novel soluble multi-site phase transfer catalyst (MPTC), viz., 2,4,6-tris(triethylammoniummethylene chloride) mesitylene (TTEAMCM) containing three active sites was synthesized and characterized through FT-IR, 1H NMR, 13C NMR and [chloride ion] analyses. The spectral and [chloride ion] results strongly confirm the presence of three active sites in the catalyst. The catalytic efficacy of this new soluble MPTC was examined by determining the pseudo-first order rate constant for dichlorocarbene addition to α-pinene reaction using low concentration of NaOH (20%) at 40 °C and comparing the observed rate constant with the rate constant of the same reaction catalyzed by commercially available single-site PTCs under identical reaction conditions. The observed result shows that TTEAMCM has a higher reactivity (≈threefold) than the single-site PTCs in terms of rate constant. Further, a thorough kinetic study was conducted for dichlorocarbene addition to α-pinene using TTEAMCM by varying the experimental parameters such as stirring speed, [substrate], [NaOH], [catalyst] and temperature and it was found that the rate constants show dependence on all the experimental parameters. The activation energy and thermodynamic parameters viz., enthalpy, entropy and free energy change were also calculated. Based on the observed kinetic and thermodynamic parameters, an interfacial mechanism was proposed for dichlorocarbene addition to α-pinene.

Graphical abstractA novel soluble multi-site phase transfer catalyst containing three active sites was synthesized and characterized. The catalytic efficacy was examined through dichlorocarbene addition to α-pinene reaction using NaOH (20%, w/w) at 40 °C and compared with commercial single-site PTCs under identical reaction conditions. A detailed kinetic study was conducted for dichlorocarbene addition to α-pinene using TTEAMCM.Figure optionsDownload full-size imageDownload as PowerPoint slide