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Interfacial Generation of a Carbanion: The Key Step of PTC Reaction Directly Observed by Second Harmonic Generation
Author(s) -
Hamkalo Michal,
Fita Piotr,
Fedorynski Michal,
Makosza Mieczyslaw
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201705597
Subject(s) - carbanion , phase (matter) , chemistry , adsorption , aqueous two phase system , second harmonic generation , ion , catalysis , aqueous solution , ion exchange , inorganic chemistry , chemical physics , organic chemistry , physics , optics , laser
We present the first unambiguous evidence of the interfacial mechanism of phase‐transfer catalysis (PTC) by direct observation of the formation of carbanions in the interfacial region between the aqueous and the organic phase by using a surface‐sensitive spectroscopic method known as second harmonic generation (SHG). Ion exchange of carbanions adsorbed at the surface after addition of lipophilic tetraalkylammonium salts (TAA) to organic phase and transport of the lipophilic ion‐pairs to the organic phase is observed. Results allow for the formulation of a more detailed mechanism of PTC.