Richard Edward Fernandez

PERSISTENT PERFLUOROALKYL RADICAL INVESTIGATIONS UNDER REDUCTIVE ENVIRONMENT : REACTION WITH ELECTRON-DONATING REAGENTS

Abstract The reactivity of persistent perfluoroalkyl radical, perfluoro-3-ethyl-2,4-dimethyl-3-pentyl ( 1 ), with various electron-donating reagents was investigated. It is revealed that 1 which is robust under oxidative conditions is rather vulnerable under reductive conditions. Thus, Lewis bases such as triethylamine and triphenylpnictogens (Ph 3 Pn, Pn=N, P, As, Sb, Bi) and some soft anions such as iodide or tetraphenyl borate reacted with 1 to give perfluoro-3-isopropyl-4-methylpent-2-ene ( 2 ) quantitatively. Even very weak Lewis bases such as diethyl ether and diethylsulfide also reacted with 1 to give 2 and additionally a hydrido product, perfluoro-3-ethyl-3- H -2,4-dimethylpentane ( 4 ). Hydrogen gas did not react with 1 at all without a catalyst, but in the presence of metal Pd adsorbed on charcoal, smoothly reacted to give 2 in quantitative yield. Metal hydrides such as LiAlH 4 , NaBH 4 , NaH, BH 3 (THF complex), Bu 3 SnH, Me 2 PhSiH reacted with 1 to give 2 and 4 . That an electron transfer mechanism is operating in the formation of 2 is obvious, but not conclusive in the formation of 4 .

Fluorocarbon synthesis: halogen exchange fluorination with alkali metal polyhydrogen fluorides

Abstract A variety of fluorocarbons of current interest can be efficiently prepared via halogen exchange fluorination with alkali metal polyhydrogen fluorides, MF·nHF, where M = K, Rb, Cs or mixtures thereof and n = 0.5 to 3. [R.E. Fernandez, et al., US Pats. 4 990 701, 4 990 702 and 5 045 634 (1991)]. The alkali metal polyhydrogen fluorides can be thought of as ‘participatory solvents’ for traditional alkali metal fluoride halogen exchange reactions, since the amount of free fluoride can be readily controlled by the addition/ removal of HF as well as by varying the temperature. Thus, by controlling “n”, this methodology can be used not only for substitution reactions, but HF addition and HF elimination reactions as well. Once the desired halogen exchange/addition/elimination has taken place, the fluoride source can be easily regenerated via the addition of HF and removal of HCl. The chemical and physical properties of these systems as well as their applicability towards fluorocarbon synthesis will be presented.