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The gas-phase pyrolysis of several aliphatic 1,3-diols. The kinetic and mechanism of 2,4-dimethyl-2,4-pentanediol

✍ Scribed by Gabriel Chuchani; Rosa M. Dominguez; Alexandra Rotinov; Ignacio Martin

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 124 KB
Volume: 29
Category: Article
ISSN: 0538-8066
DOI: 10.1002/(sici)1097-4601(1997)29:11<851::aid-kin6>3.0.co;2-l

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✦ Synopsis

Satisfactory kinetic determinations of several aliphatic 1,3-diols were difficult to obtain. Moreover the product distributions from each of these substrates suggest complex parallel mechanisms. However, the elimination kinetic of 2,4-dimethyl-2,4-pentanediol has been measured over the temperature range of 419.7-459.9ЊC and pressure range of 47-115 torr. The reaction carried out by employing a static system, in seasoned vessel, and in the presence of the free-radical inhibitor propene, proved to be homogeneous, unimolecular, and follows a first-order rate law. The products are acetone, isobutene, and H 2 O. The rate coefficient is expressed by the following Arrhenius equation: Ϫ1 log k (s ) ϭ (12.53 Ϯ 0.58) Ϫ 1 kJ mol Ϫ1 (2.303RT) Ϫ1 . The pyrolytic elimination of this substrate is believed to (217.3 Ϯ 8.0) proceed through a concerted six-membered cyclic transition-state type of mechanism.

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