Inverse phase transfer catalysis: kinetics of the pyridine 1-oxide-catalyzed two-phase reactions of fluoro- and butyl-benzoyl chlorides and benzoate ions

Abstract

The substitution reactions of XC 6H 4COCl (X=2-F, 3-F, 4-F, or 4-(CH 3) 3C) and YC 6H 4COONa (Y=2-F, 3-F, 4-F, or H) in a two-phase H 2O/CH 2Cl 2 medium using pyridine 1-oxide (PNO) as an inverse phase transfer catalyst were investigated. Under suitable reaction conditions, the kinetics of the reaction follows a pseudo-first-order rate law, with a constant observed rate being a linear function of the concentration of PNO in the water phase. The order of reactivities of XC 6H 4COCl toward reaction with PNO is 2-FC 6H 4COCl>3-FC 6H 4COCl>4-FC 6H 4COCl>C 6H 5COCl>4-(CH 3) 3CC 6H 4COCl. The order of reactivities of YC 6H 4COO − ions toward reaction with 1-(benzoyloxy)pyridinium (C 6H 5COONP +) ion is C 6H 5COO −>3-FC 6H 4COO −>4-FC 6H 4COO −>2-FC 6H 4COO −. For the water phase with pH>12, the reaction is complicated by the competitive reaction of XC 6H 4COCl and OH − ion in the organic phase.