Détail de la notice
Titre du Document
Mechanism and kinetics of the acid-catalyzed dehydration of 1- and 2-propanol in hot compressed liquid water
Auteur(s)
ANTAL M. J. ; CARLSSON M. ; XIAODONG XU ; ...
Résumé
Only propene and 1-propanol are observed as products of the acid-catalyzed dehydration of 2-propanol in compressed liquid water after 100 s or less at 320°C. Likewise, only propene, 2-propanol, and traces of n-propyl ether are observed as products of the acid-catalyzed dehydration of 1-propanol under the same conditions. Kinetic analyses of the experimental data indicate that propene is formed from 1-propanol by an acid-catalyzed E2 mechanism that involves only protonated 1-propanol as an intermediate. Byproduct n-propyl ether is formed by an AdE3 mechanism involving propene, 1-propanol, and acid. The formation of propene from 2-propanol is kinetically consistent with both an acid-catalyzed E2 mechanism and an acid-catalyzed E1 mechanism (that involves the bare i-propyl cation in addition to protonated 2-propanol as intermediates in the dehydration chemistry). Thus, the kinetic analysis does not enable to discriminate between the two mechanisms for 2-propanol dehydration. On the other hand, results of the kinetic analysis point to the important role of the undetected product i-propyl ether in the formation of propene from both 2-propanol and 1-propanol. This ether (which is not stable in hot liquid water) is formed by an AdE3 mechanism and decomposes via an uncatalyzed, unimolecular reaction. Experimental studies of the reactions of n-propyl ether and i-propyl ether are consistent with model predictions.
Editeur
American Chemical Society
Identifiant
ISSN : 0888-5885 CODEN : IECRED
Source
Industrial & engineering chemistry research A. 1998, vol. 37, n° 10, pp. 3820-3829 [bibl. : 28 ref.]
Langue
Anglais
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