TieJun Zhang, R. Datta
Feb 1, 1996
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0
Influential Citations
14
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Journal
Chemical Engineering Science
Abstract
Abstract The thermodynamic equilibria and kinetics of the reaction network involved in the liquid-phase synthesis of 3-methyl-3-ethoxy--pentane (THEE3), one of the three isomers of t -hexyl ethyl ether (THEE) formed from the etherification reactions of C 6 tertiary olefins with ethanol, are described here. This ether is potentially of interest as an oxygenate for blending with gasoline for octane enhancement and air quality improvement. The coupled reaction network of THEE3 synthesis involves three simultaneous etherification and three isomerization reactions, all of which are reversible. Equilibrium and kinetics experiments were conducted over the temperature range of practical interest, i.e. 298 to 353 K, over Amberlyst 15 resin catalyst. Expressions for the thermodynamic equilibrium constants, K i = K xi K yi , were developed based on the experimental equilibrium composition used to calculate K xi and the corresponding activity coefficients estimated by the UNIFAC method to compute K yi . Reaction rate expressions in terms of species activities were developed based on the data obtained in a differential packed-bed reactor, and were subsequently tested for reliability in the prediction of integral packed-bed reactor performance. The rate expressions are based on the LHHW formalism involving a dual-site surface etherification reaction and a single-site surface isomerization reaction as the rate-limiting steps, along with the assumption of adsorbed ethanol as the most abundant surface species.