Catalysis by hydrogen chloride in the gas‐phase elimination kinetics of 2‐phenyl‐2‐propanol and 3‐methyl‐1‐buten‐3‐ol |
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| Authors: | Rafael J Rasse Rosa M Domínguez Armando Herize Maria Tosta Doris Brusco Gabriel Chuchani |
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| Institution: | 1. Departamento de Química, Universidad de Oriente, Cumana, Sucre, Venezuela;2. Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas 1020‐A, Venezuela;3. Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas 1020‐A, VenezuelaCentro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado 21827, Caracas 1020‐A, Venezuela.=== |
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| Abstract: | A homogeneous, molecular, gas‐phase elimination kinetics of 2‐phenyl‐2‐propanol and 3‐methyl‐1‐ buten‐3‐ol catalyzed by hydrogen chloride in the temperature range 325–386 °C and pressure range 34–149 torr are described. The rate coefficients are given by the following Arrhenius equations: for 2‐phenyl‐2‐propanol log k1 (s?1) = (11.01 ± 0.31) ? (109.5 ± 2.8) kJ mol?1 (2.303 RT)?1 and for 3‐methyl‐1‐buten‐3‐ol log k1 (s?1) = (11.50 ± 0.18) ? (116.5 ± 1.4) kJ mol?1 (2.303 RT)?1. Electron delocalization of the CH2?CH and C6H5 appears to be an important effect in the rate enhancement of acid catalyzed tertiary alcohols in the gas phase. A concerted six‐member cyclic transition state type of mechanism appears to be, as described before, a rational interpretation for the dehydration process of these substrates. Copyright © 2007 John Wiley & Sons, Ltd. |
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| Keywords: | elimination gas‐phase kinetics hydrogen chloride catalyst mechanism 3‐methyl‐1‐buten‐3‐ol and 2‐phenyl‐2‐propanol |
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