THE THERMODYNAMIC EFFECT OF FLUORINE AS A SUBSTITUENT VINYLIC CF2 AND CFH AND ALLYLIC CF2C

Article abstract of DOI:10.1016/0040-4020(82)87020-8

I2-catalyzed isomerizations of 3-fluoropropene and 3,3-difluoropropene, and a Cope rearrangement of 1,1-difluoro-1,5-hexadiene provide thermodynamic data which allow the determination of a number of important group values for contributions to ΔH_f⁰ which when combined with those determined in the preceding paper allow the calculations of ΔH_f⁰'s of most simple F-substituted hydrocarbons: d-(F)(H)>= -38.4, d(F)2>= -88.0, d)>= -103.9, = -104.9 kcal/mole.A kinetic study of the conversion of 1,1-difluoro- to 3,3-difluoro-1,5-hexadiene provided activation parameters for the process: Log A= 10.8, E_a= 33.0 kcal/mole and ΔS^*= -12.2 e. u.Incremental geminal stabilizations of F and other substituents are discussed and contrasted.