The high-temperature pyrolysis of hexachloropropene: Kinetic analysis of pathways to formation of perchloro-arylbenzenes

✍ Scribed by Philip H. Taylor; Debra A. Tirey; Barry Dellinger

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 806 KB
• Volume: 105
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(95)00118-2

✦ Synopsis

We present the results of a study of the thermal degradation of hexachloropropene in a tubular flow reactor with in-line GC-MS product analysis. Hexachloropropene was observed to be thermally fragile with initial reaction products (T < 773 K) including CCI 4, C2C14, C2C16, and C3C14, (a). At higher temperatures (up to 1223 K), pronounced molecular growth was observed with reaction products including C4C16, C6C16 (cy), C6C18, C8C1 s (cy), and C12C18 (cy). Kinetic modeling of observed product yields indicated that CI displacement of CCI 3 radicals was the dominant initiation pathway for conversion of C3CI 6 into C2C14, CCl4, and C2C16. Four reaction submodels were considered in developing a model for the formation of C6C16 (cy): recombination of C3CI 5, recombination of C3C13, pericyclic addition of C3C14 (a), and addition reactions of C 2 and C a unsaturated radicals with C2C12. Recombination of C3C15 radicals accounted for all of the observed yields at low temperatures (T < 873 K). At higher temperatures, C3C13 recombination accounted for about 80% of observed yields with C3C15 recombination accountable for the remainder. Purely C a radical-molecule reactions were also shown to make significant contributions to formation of octachlorostyrene (C8C18 (cy)). Consequently, the more conventional C 2 molecular growth pathways were observed to be insignificant for this system.