Kinetics of methyl tertiary butyl ether liquid phase synthesis catalyzed by ion exchange resin—II. Macropore diffusion of methanol as rate-controlling step

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The microkinetic model for methyl tertiary butyl ether (MTBE) synthesis presented in an earlier work is extended to the case of macropore diffusion of methanol as the rate-controlling step. Experimental results concerning the activity and selectivity of the sulfonic acid ion exchange resin catalyst were in agreement with a shell-core model, according to which almost none of the methanol-containing core produces the by-product diisobutene while only the outer shell forms the main product MTBE. Experimental effectivenss factors (η) for the isothermal catalyst beads were determined up to η = 5, while the theoretically calculated corresponding η was two-thirds of this value. The limiting effective diffusion coefficient of methanol (in a C 4 mixture of isobutene and 1-butene) in an Amberylst 15 resin was used as an adjustable parameter and found to be 3.5 × 10 −9 m 2/s at 333 K.