ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Pyrolysis of cis-butene-2 under conditions of very low pressure (VLPP) has been studied in the range of 1100-1300°K. The principal products are butadiene and H2, obtained in a unimolecular reaction. A competing reaction to form butene-l accounts for from 10% to 40% of the overall decomposition over the range. Using a «tight» model for the transition state and RRKM theory yields a high-pressure, unimolecular rate constant for the 1,4-H2 elimination of \documentclass{article}\pagestyle{empty}\begin{document}$$ \log \,k\left( {{\rm s}^{ - 1} } \right) = \left( {13.0 \pm 0.6} \right) - {{\left( {65 \pm 2} \right)} \mathord{\left/ {\vphantom {{\left( {65 \pm 2} \right)} \theta }} \right. \kern-\nulldelimiterspace} \theta } $$\end{document} where θ = 2.303RT in kcal/mol. There is some surface reaction of butadiene at these temperatures to yield H2 + nonvolatile residue. Butene-l proceeds to decompose irreversibly to allyl + methyl radicals which have been observed directly. Comparison with related reactions leads to the conclusion that orbital symmetry-forbidden, 1,2-H2 elimination from saturated organic compounds will have activation energies too high to observe.
Additional Material:
5 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550050608
