Dechlorination of poly(vinylidene chloride) in NaOH/ethylene glycol as a function of NaOH concentration, temperature, and solvent

Abstract

The wet dechlorination treatment of poly(vinylidene chloride) (PVDC) was evaluated at atmospheric pressure in a solution of NaOH in ethylene glycol (EG), as a function of NaOH concentration, temperature, and solvent. Hydroxide ion from NaOH was required for dechlorination with EG acting solely as a solvent. The wet treatment exhibited significantly enhanced dechlorination efficiency over traditional thermal techniques, with a reaction efficiency as high as 92.8% in 1.0 M NaOH at 190 °C. Dechlorination reactions of PVDC in both NaOH/EG and NaOH/H 2O were expressed by an apparent first-order reaction. At 190 °C, the apparent rate constant in 1.0 M NaOH/EG was approximately 1.4 times larger than in 1.0 M NaOH/H 2O, with an apparent activation energy of 82.8 kJ mol −1, indicating that the reaction proceeded under chemical control. The degree of dechlorination increased with increasing reaction temperature, favouring the elimination of HCl over the hydroxyl substitution of chloride.