Kinetic studies of the dehydrochlorination of 1,2-dichloroethane on alumina supported copper(II)chloride catalysts
Tóm tắt
Microreactor and kinetic isotope techniques have been used to study the mechanism and kinetics of the surface dehydrochlorination of 1,2-dichloroethane over alkali metal chloride modified copper(II) chloride onγ-Al2O3 catalysts. A first order rate law is obeyed and the rate constant decreases progressively on addition of LiCl, NaCl, KCI or RbCI to the copper catalyst but increases again on addition of CsCl; the changes arise mainly from changes in the activation energy. A primary kinetic isotope ratiok
H/k
D = 1.87 at 285°C is observed for perdeutero 1,2-dichloroethane on the unmodified catalyst indicating the C-H bond breaking occurs in the rate determining step. Changes ink
H/k
D on addition of the alkali chlorides parallel those ofk
H. The rate determining step changes smoothly from one involving C-H bond breakage to one involving C-Cl bond breakage as the catalyst is modified with alkalichlorides.
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