Tri-n-butylin hydride reduction of poly(vinyl chloride); kinetics of dechlorination for 2,4-dichloropentane and 2,4,6-trichloroheptane.

2,4-Dichloropentane (DCP) and 2,4,6-trichloroheptane (TCH) were reductively dechlorinated with tri-n-butyltin hydride ((n-Bu)(3)SnH) directly in the NMR sample tube. Carbon-13 NMR spectra were recorded periodically to monitor the progress of DCP and TCH dechlorination. From these observations the following kinetic conclusions were drawn: i. meso (m)DCP was reduced 30% faster than racemic (r) DCP; ii. the Cl from DCP was removed 4 times faster than the Cl in 2-chloropentane or 2-chlorooctane; iii. the 4-Cl in mm-TCH is removed faster than the 4-Cl in mr-TCH which in turn is more readily removed than the 4-Cl in the rr isomer; and iv. the 4-Cl in TCH is removed 1.5 times faster than the 2- or 6-Cl's. Conclucions i. and ii. were previously observed at the dyad level, at least qualitatively, in the (n-Bu)(3)SnH reduction of poly(vinyl chloride) (PVC) to ethylene-vinyl chloride (E-V) copolymers.