The reverse-flow chromatographic reactor (RFCR) utilizes a mixture of catalyst and adsorbent to simultaneously react and separate. The adsorbent more strongly adsorbs the reactant than the products. After the desired products exit the reactor, the flow direction is reversed, thereby trapping the reactant and increasing the overall conversion. This combination of separation and reaction in the RFCR increases the yield in equilibrium reactions and can reduce the amount of the secondary products in a consecutive reaction system.

Hexane was isomerized in a RFCR filled with a uniform packing of Pt-Mordenite catalyst (10 g) and 5A molecular sieve (32 g). The resulting products for a space velocity of 0.05-0.09 g hexane/g catalyst*hr were a mixture of the hexane isomers with trace amounts of byproducts. Overall conversions at 220 C ranged from 93.1-73.4%, which is higher than the PFR conversion of 60.6% and the equilibrium conversion of 87.5% at 500 K.

For a given space velocity, product selectivity remained relatively stable when varying the switching time from 5-40 minutes. The selectivity for the mixture of 2-methylpentane and 2,3-dimethylbutane ranged from 57.5-60.2%, for 3-methylpentane from 29.8-30.9%, and for 2,2-dimethylbutane from 8.9-12.4%. The capillary column could not separate the peaks of 2-methylpentane and 2,3-dimethylbutane. The RFCR was able to exceed the equilibrium selectivities (at 500 K) of 2-methylpentane/2,3-dimethylbutane (39%) and 3-methylpentane (13.7%), but not for 2,2-dimethylbutane (47.3%). Pure streams of 2-methylpentane and 3-methylpentane were each injected as a reactant into the RFCR. The resulting selectivities for each was comparable to that when using hexane as the reactant.

Breakthrough analysis has shown that the 5A adsorbs hexane, but not the branched isomers. When mixed with the Pt-Mordenite catalyst, the packed bed separates the hexane isomers from each other, which results in the system being able to separate the single-branched isomers from the the multi-branched ones. This allows the RFCR to have control over the product distribution by changing the switching time.