Studies of the pyrolysis of diethylzinc by the toluene carrier method and of the reaction of ethyl radicals with toluene

Abstract

The thermal decomposition of diethylzinc in a toluene carrier system has been studied over the temperature range of 669 to 762 K , and percent decomposition of 3.8 to 97.2%. The decomposition occurs by a two step mechanism, the second step rapidly following the first, The overall progress of the reaction was followed by determination of the residual diethylzinc by hydrolysis followed by analysis for zinc by atomic absorption. In selected runs two additional methods were used: (i) measurement and analysis of the gas evolved during the hydrolysis and (ii) full analysis of all pyrolysis products involving the C2Hs group.In the absence of zinc oxide the decomposition is essentially homogeneous and log kl (s-1) = 14.3 + 0.6 -49 000 * 2 000 4.58Tor -205 000/19.15T if the activation energyi s expressed inj oules rather than calories. The presence of zinc oxide causes marked catalysis of the overall decomposition but does not appear to affect reaction 3 or reaction 6.[61 CzHs + C2H4 + H 9 800 + 500 log k3 (cc mol-1 s-1) = 11.12 + 0.15 -4.58T 30 300 (at 15 mm pressure) log k6 (s-I) = 11.0 -- 4.58TReaction 6 is in a strongly pressure dependent region and is based on very limited data.AHTI A. KOSKI, S. JAMES W. PRICE et BARRY C. TRUDELL. Can. J. Chem. 54, 482 (1976). On a CtudiC la dCcomposition thermique du dikthylzinc dans un systkme contenant du tolukne comme diluant ; ces Ctudes ont Ct C rCalisCes entre 669 et 762 K et amenCes des pourcentages de dCcomposition de 3.8 a 97.2%. La dCcompositio11 se produit par un mkanisme en deux Ctapes; la deuxikme Ctape suit rapidement la premiere On a suivi le progrks globale de la reaction en determinant le dikthylzinc rCsiduel par une hydrolyse suivie par une analyse du zinc par absorption atomique. Dans un certain nombre de cas spicifiques, on a utilisC deux methodes supplCmentaires: (i) la mesure et l'analyse du gas qui s'Cchappe au moment de l'hydrolyse et (ii) l'analyse compl'ete de tous les produits de pyrolyse impliquant le groupe C2H5.

Rate constants for abstraction of hydrogen from benzene, toluene, and cyclopentane by methyl and ethyl radicals over the temperature range 650–770 K

“…The activation energy and frequency factor for reaction [12] are in good agreement with the values obtained by Price and co-workers (18,19,32,33) …”

“…[19] is approximate when applied to the measured activation energies, an examination of the qualitative relation between activation energy and bond dissociation energy for a particular elementary reaction may offer new insights into the results. In particular, the activation energies measured in the present study for abstraction from unsaturated hydrocarbons appear more realistic in relation to the dissociation energies of the reactants than the values recommended by Kerr and Parsonage.…”

Kinetics of the Hydrogen Abstraction •CH3 + Alkane → CH4 + Alkyl Reaction Class: An Application of the Reaction Class Transition State Theory

“…C 2 H 6 . Experimental reaction rates for those cyclic systems were previously reported in a number of studies [51][52][53]. Figure 7a-f shows the predicted rate constants of these reactions using the RC-TST method and from the literature data.…”

Pyrolysis of triethylgallium by the toluene carrier technique

“…showed a reasonable degree of agreement when rate Experimental constants were compared. The toluene carrier work M~~~~~~~,~ on diethylzinc (6) showed marked catalysis by zinc ii, oxide. In the absence of zinc oxide log A (s-I) = 14.3…”