53586-62-2Relevant academic research and scientific papers
Conformation in 2,3-Difluorobutanes
Angelini, G.,Gavuzzo, E.,Segre, A. L.,Speranza, M.
, p. 8762 - 8766 (2007/10/02)
A conformational analysis for meso- and d,l-2,3-difluorobutanes has been carried out, employing 1H and 19F NMR and theoretical calculations.The real configurations of the two isomers were assigned by specific optical rotation measurements of the products coming from an optically active precursor.Gauche conformations were predominant for meso (E) isomer, while the d,l (T) isomer showed all possible staggered rotamers almost equally populated.Finally remarks for NMR peak assignment of homo- and copolymers partially fluorinated by using gauche additive effects are given.
Stereochemical Consequences of Halogen Atom Substitution. 1. Rotational Conformer Effects in Gaseous Diastereomeric 2,3-Dihalobutanes
Sharma, Ram B.,Ferrieri, Richard A.,Meyer, Richard J.,Rack, Edward P.,Wolf, Alfred P.
, p. 2316 - 2320 (2007/10/02)
The stereochemical consequences of translationally excited 38Cl-for-X (X = F, Cl) substitution in (2S,3R)-meso- and (2S,3S)-dl-difluorobutane, (2S,3R)-dl- and (2S,3R)-dl-chlorofluorobutane, and (2S,3R)-meso- and (2S,3S)-dl-dichlorobutane were studied in the gas phase.Although retention of configuration was determined to be the dominant substitution pathway, substantial inversion product yields were observed in all cases.A comparison of these yields revealed that the (S,R) configuration within each set always gave a smaller yield of the inverted product than the (S,S) configuration.This observation was consistent with the hypothesis that back-side substitution was a direct mechanism and that steric hindrance to such attack was subject to differences in the rotational conformer populations within each substrate configuration.In contrast, the measured yields of retention products were insensitive to substrate configuration.
Reaction of OH with CH3CH2F. The Extent of H Abstraction from the α and β Positions
Singleton, Donald L.,Paraskevopoulos, George,Irwin, Robert S.
, p. 2339 - 2343 (2007/10/02)
The mechanism of the reaction of OH radicals with C2H5F was determined from the yields of the reaction products.Hydroxyl radicals were generated in the gas phase by photolysis of H2O at 184.9 nm, and products were analyzed by gas chromathography and mass spectrometry.The reaction proceeds by abstraction of hydrogen primarily from the α position, and the major products were meso- and d,l-2,3-C4H8F2, 1,3-C4H8F2, 2-C4H9F, and H2.The minor products were 1,4-C4H8F2, 1-C4H9F, 1-and 2-C3H7F, C2H6, C2H4, C2H3F, and C2H2.It was found that kinetically hot H atoms formed in the photolysis of H2O abstract hydrogen to some extent at the β position of C2H5F in contrast to thermal H atoms which abstract exclusively at the α position.After correction for the effects of H atom reactions, it was estimated that 85+/-3percent of the abstraction by occurs at the α position of C2H5F.
