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The substitution reactions of 2,3-, 2,4-, 3,4-, or 3,5-dichlorobenzoyl chloride (Cl 2 C 6 H 3 COCl) and 2,3-, 2,4-, 3,4-, or 3,5-dichlorobenzoate ion (Cl 2 C 6 H 5 COO − ) or benzoate ion (C 6 H 5 COO − ) in a two-phase H 2 O/CH 2 Cl 2 medium using pyridine 1-oxide (PNO) as an inverse phase transfer catalyst were investigated. The reaction of Cl 2 C 6 H 3 COCl and PNO in CH 2 Cl 2 to produce the ionic intermediate, 1-(dichlorobenzoyloxy)-pyridinium chloride (Cl 2 C 6 H 3 COONP + Cl − ) is the rate-determining step. In the PNO-catalyzed two-phase reaction of Cl 2 C 6 H 3 COCl and C 6 H 5 COONa, the order of reactivities of Cl 2 C 6 H 3 COCl toward reaction with PNO is (2,3-, 2,4-)>3,5->3,4-≫2,6-Cl 2 C 6 H 3 COCl, whereas it is 3,5->(2,3-, 3,4-)>2,4-Cl 2 C 6 H 3 COCl in the PNO-catalyzed two-phase reaction of Cl 2 C 6 H 3 COCl and the corresponding Cl 2 C 6 H 3 COONa. The order of reactivities of Cl 2 C 6 H 3 COO − ions towards the reaction with 1-(benzoyloxy)-pyridinium (C 6 H 5 COONP + ) ion is (3,4-, 3,5-)>(2,3-, 2,4-Cl 2 C 6 H 3 COO − ). |
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