836. The kinetics of the methanolysis of t-butyl chloride, bromide, and iodide

1962 ◽  
pp. 4291 ◽  
Author(s):  
Joas Biordi ◽  
E. A. Moelwyn-Hughes
Keyword(s):  
Butyl Chloride ◽  
Kinetics Of

Chemistry of the Transition Metals. II. Reaction of Branched Alkyl Chlorides with Titanium

1972 ◽  
Vol 50 (14) ◽  
pp. 2167-2174 ◽  
Author(s):  
W. R. Summers ◽  
J. F. Harrod
Keyword(s):  
Activation Energy ◽  
Elevated Temperatures ◽  
Halogen Bond ◽  
Heterogeneous Reaction ◽  
Butyl Chloride ◽  
Dissociative Chemisorption ◽  
Ambient Temperatures ◽  
Catalytic Dehydrochlorination ◽  
Titanium Surfaces ◽  
Kinetics Of

Except for t-butyl chloride, the 1- and 2-methyl substituted ethyl chlorides reacted at ambient temperatures with clean titanium surfaces to produce mixtures of the corresponding alkanes and alkenes; t-butyl chloride gave only isobutene. At elevated temperatures (80–150 °C depending on reactant) the branched alkyl chlorides underwent clean, catalytic dehydrochlorination on hydrochlorinated titanium films to give gaseous olefin and hydrogen chloride, in contrast to the previously observed dehydrohalogenation of n-alkyl halides, where metal was consumed continuously in a non-catalytic fashion.The kinetics of the dehydrochlorination were exceptionally simple and reproducible for a heterogeneous reaction and all reactions were first order in reactant. The reactivity order was t-butyl > i-propyl > neopentyl > i-butyl (ca. 106:6:3:1). Although a slight dependence of activation energy on reactant pressure was observed, all reactants gave a limiting activation energy of 15.5 ± 0.5 kcal/mol and the large variation in activity is attributed to differences in the Arrhenius pre-exponential factor.It is proposed that the non-catalytic and catalytic dehydrohalogenation reactions proceed by different mechanisms, the former via a dissociative chemisorption of the carbon–halogen bond and the latter via a concerted, surface-assisted HCl elimination.

Sign in / Sign up

Export Citation Format

Share Document