The effect of thermal processing on PVC—VI. The role of hydrogen chloride

✍ Scribed by B.B. Cooray; G. Scott

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 462 KB
• Volume: 16
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(80)90066-x

✦ Synopsis

A~lract--The reaction between cumene hydroperoxide (CHP) and anhydrous hydrogen chloride under various conditions of temperature and concentration has been studied in an inert solvent (chlorobenzene) and in an oxidisable medium (cumene). The kinetics were first order with respect to each reactant : the energy of activation of the overall second-order reaction was 53.4 kJ tool-i K-'. Competing ionic and free radical mechanisms were found to operate, the latter predominating at relatively high HCI concentrations, leading to rapid pro-oxidation in cumene. The effect of typical organt>tin PVC stabilizers on the pro-oxidant process were examined. It was found that dibutyltin maleate neutralized the HCI thus eliminating the pro-oxidant effect when used in stoichiometric proportions, but had little other effect. Dioctyltin bis(isol-octylthioglycollate) on the other hand not only neutralized the HCI stoichiometrically but gave additional oxidative stabilization over a wide concentration range.