Dehydration of (Perfluoroalkyl)tetramethylcyclopentenols

0369888 - ÚCHP 2012 RIV CH eng J - Journal Article
Čermák, Jan - Nguyen Thi, T.H. - Včelák, Jaroslav - Krupková, Alena
Dehydration of (Perfluoroalkyl)tetramethylcyclopentenols.
Molecules. Roč. 16, č. 5 (2011), s. 4031-4044. E-ISSN 1420-3049
R&D Projects: GA AV ČR IAA4072203; GA MŠMT(CZ) LC06070
Institutional research plan: CEZ:AV0Z40720504
Keywords : dehydration * fluorous cyclopentadienes * cyclopentenols
Subject RIV: CC - Organic Chemistry
Impact factor: 2.386, year: 2011

Perfluoroalkyl tetramethylcyclopentenols (alkyl = n-butyl, n-hexyl, n-octyl) were dehydrated to a complex mixture of endo, endo-(perfluoroalkyl) tetramethyl-cyclopentadienes and their endo-, exo-isomers. It was found in preliminary screening experiments that the best reagent for this transformation, giving an 89% yield of isomeric product mixture, was P2O5 in benzene at 80-90 °C. Products were characterized on the basis of their mass spectra and retention time information, and some peaks in the mass spectra were identified from their molecular fragments. Structures were assigned to the three most abundant products of (perfluorohexyl)tetramethylcyclopentenol dehydration. Formal dehydration kinetics showed a second order reaction in benzene but zeroth order with induction period in chlorobenzene, suggesting mass transfer limitations in the more polar chlorobenzene. Some of the products were formed by consecutive isomerization of the others, as shown by the kinetic analysis.
Permanent Link: http://hdl.handle.net/11104/0203849