Kinetics of the Thermal Cis-Trans Isomerization of Dideuteroethylene

Abstract

The thermal cis-trans isomerization of trans-ethylene, d2 has been studied from 450° to 550°C over a pressure range of 0.9 cm to 31 cm Hg in two quartz reactors. The rate is pressure dependent over the entire pressure range. It is concluded that at 0.9 cm the reaction is a homogeneous, unimolecular reaction. A high pressure activation energy of 65 kcal and frequency factor of 1013 sec—1 are deduced. At higher pressures the reaction is sensitized by processes attendant on polymerization, which occurs as a side reaction with propylene as the principal product. The relation of this study to other work on substituted ethylenes is discussed briefly, as well as a few other topics pertinent to the results obtained.

A comparison of some properties of C=O and C=S bonds

“…In some cases, such as ethene, it is possible to derive the π bond strength from the rotational barrier. 8 This is clearly not possible with the present compounds. The strength of a C-O or C-S single bond may be taken as the D 298 of methanol and methanethiol.…”

Recent Progress in Quinoidal Singlet Biradical Molecules

“…60 At the same time, some aromatic sextets are newly generated during the transformation. The aromatic stabilization energy of benzene, based on the homodesmic stabilization energy, is ca.…”

A polarized, twisted, ethylene: structure of 3,3-bis(methylthio)-2-nitro-2-propene-1-nitrile, C5H6N2O2S2

“…The C=C torsional barrier in 1,2-dideuterioethylene is 261.2kJmo1-1 (Douglas, Rabinovitch & Looney, 1955). Push-pull substituents on ethylene considerably lower the free energy of activation (AG ~) to rotation around the double bond to below 105 kJ mo1-1.…”