ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Pyrolysis of atactic polypropylene

P. Drienovský and Ondrej Kyseľ

Slovak Academy of Sciences, Bratislava

Abstract: The thermal degradation of atactic polypropylene (I) in a stream of H was studied with a previously described app. (CA 60, 14609e). Samples of I (3-4 mg.) were pyrolyzed 11.6 sec. on an elec. heated Pt foil; the temp. was controlled by a Pt-PtRh thermocouple. The gaseous decompn. products were detd. by gas chromatography. Decompn. is very slow up to 300°. Above 320°, the main decompn. product is C₃H₆; its concn. reaches a max. at 720°. The yield of C₃H₆ is unexpectedly high, owing to its rapid removal from the reaction zone by the carrier gas. Under stationary conditions, considerably smaller amts. of C₃H₆ are found because it undergoes decompn. in the reaction zone. Above 720°, the yield of C₃H₆ declines; CH₄ and C₂H₄ in roughly equal amts. become the principal decompn. products. The 1:1 ratio is probably due to their formation by decompn. of the Pr radical. The amt. of C₂H₄ decreases after reaching a max. at 860°, while the amt. of CH₄ continues to rise steeply. C₂H₂, which is first found at 720°, also continues to increase with increasing temp. Other decompn. products are ethane, propane, and trans-2-butene; if the sample size is increased to 5.5 mg., isobutylene, 1-butene, and cis-2-butene are also found. The various decompn. products are formed by isomerization of •CH[CH₂CH(Me).sbd.]2 to other macroradicals, e.g. -CH(Me)CH₂CH₂CH₂CH(CH₂•)CH₂.sbd., followed by scission.

Full paper in Portable Document Format: 187a512.pdf (in Slovak)

Chemical Papers 18 (7) 512–526 (1964)