caa a22 4500 469059141 CHVBK 20180323132852.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF01053859 doi (NATIONALLICENCE)springer-10.1007/BF01053859 Influence of quaternary onium salts, crown ethers and cryptands on olefin epoxidations promoted by HOCl/ClO− in the Presence of Mn(III)-tetrakis(2,6-dichlorophenyl)porphyrin chloride [Elektronische Daten] [Stefano Banfi, Fernando Montanari, Silvio Quici, Gaguik Torossian] Reaction rates of alkene epoxidations, promoted by aqueous NaOCl and catalyzed by Mn(III)-tetrakis(2,6-dichlorophenyl)porphyrin chloride1 (P) in the presence of a lipophilic axial ligand (L) (e.g.N-hexylimidazole) and carried out under H2O/CH2Cl2 two phase conditions at 0°C, are strongly enhanced by lowering the pH of the aqueous phase from 12.7 to 9.5. Under these conditions, a further relevant increase in the reaction rates can be achieved by adding phase-transfer catalysts (PT), e.g. quaternary ammonium salt 3, lipophilic crown ether4 or cryptand5, provided that the amount of L is very small (L/P=1 for very reactive alkenes, e.g. cyclooctene, and 10 for poorly reactive ones, e.g. 1-dodecene). In the case of cyclooctene epoxidation, the use of 0.006-0.03 mol. equiv. of PT completes the reaction in 1-10 min., the initial rates being up to 600 turnovers/min. with (2.2.2,C10) cryptand. In the absence of the axial ligand, the quaternary ammonium salt3 and cryptand5 show an inhibitory effect. Such an effect is due to the formation of the poorly reactive Mn(P)CI species, by Cl− extraction to the organic phase. However, dibenzo crown ether 4 does not show this effect. In the presence of 4, and with L/P =1, the 1-dodecene epoxidation reaches 94% in 1 min. The ‘unique' behavior of crown ethers can be explained by their ineffectiveness in extracting alkali chlorides, providing a very low concentration of Cl− in the organic phase and thus avoiding the Mn(III)-porphyrin deactivation. Kluwer Academic Publishers, 1992 Mn(III)-tetraarylporphyrin nationallicence olefin epoxidations nationallicence HOCl/ClO− nationallicence two-phase conditions nationallicence influence of phase-transfer catalysts nationallicence effect of Cl− nationallicence competitive extraction of Cl− and ClO− nationallicence quaternary onium salts nationallicence crown ethers nationallicence cryptands nationallicence Banfi Stefano Centro CNR and Dipartimento di Chimica Organica e Industriale dell'Università, Via Golgi 19, 20133, Milano, Italy aut Montanari Fernando Centro CNR and Dipartimento di Chimica Organica e Industriale dell'Università, Via Golgi 19, 20133, Milano, Italy aut Quici Silvio Centro CNR and Dipartimento di Chimica Organica e Industriale dell'Università, Via Golgi 19, 20133, Milano, Italy aut Torossian Gaguik Chemical Department, Polytechnical Institute, Erevan, 375009, Armenia, USSR aut Journal of inclusion phenomena and molecular recognition in chemistry Kluwer Academic Publishers 12/1-4(1992-01-01), 159-173 0923-0750 12:1-4<159 1992 12 10847 https://doi.org/10.1007/BF01053859 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01053859 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Banfi Stefano Centro CNR and Dipartimento di Chimica Organica e Industriale dell'Università, Via Golgi 19, 20133, Milano, Italy aut NATIONALLICENCE 700 1- Montanari Fernando Centro CNR and Dipartimento di Chimica Organica e Industriale dell'Università, Via Golgi 19, 20133, Milano, Italy aut NATIONALLICENCE 700 1- Quici Silvio Centro CNR and Dipartimento di Chimica Organica e Industriale dell'Università, Via Golgi 19, 20133, Milano, Italy aut NATIONALLICENCE 700 1- Torossian Gaguik Chemical Department, Polytechnical Institute, Erevan, 375009, Armenia, USSR aut NATIONALLICENCE 773 0- Journal of inclusion phenomena and molecular recognition in chemistry Kluwer Academic Publishers 12/1-4(1992-01-01), 159-173 0923-0750 12:1-4<159 1992 12 10847 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer