Separation of C5 paraffin isomers by vanadotungstate-based zeolitic octahedral metal oxides under high temperature and humidity.

Efficient separation of n-pentane and isopentane is vital for light naphtha upgrading. Herein, a series of vanadotungstate-based octahedral metal oxides (ZOMO-3-VW-cubic) were synthesized and evaluated for pentane isomer separation. Single-component adsorption experiments combined with theoretical selectivity calculations reveal that the materials preferentially uptake n-pentane and cation species affected the selectivity. Breakthrough experiments identified ZOMO-3-VW-cubic with Na+ as the cation (ZOMO-3-NaVW-cubic) as the best-performing adsorbent. Operating conditions for separation, such as flow rate, temperature and humidity, were evaluated. Further investigations combining simulation and isosteric heat of adsorption analysis demonstrated that the separation was dominated by a kinetic molecular sieving effect. This work provides a robust and selective vanadotungstate sieve for C5 isomer separation with clear mechanistic understanding.