Molecular sieving of di‐branched hexane isomers in a self‐adaptive adsorbent for benchmark <scp>research octane number</scp> gasoline production

Abstract Effective separation of isomers is critical in various industrial applications, particularly in the production of high research octane number (RON) gasoline. This study introduces a novel flexible adsorbent, NCU‐542 ([Zn‐BTEC‐TEIB] [H 4 BTEC = pyromellitic acid, TEIB = 1,2,4,5‐tetra(1 H ‐imidazol‐1‐yl)benzene]), featuring self‐adaptive pore systems for the molecular sieving of di‐branched 2,3‐dimethylbutane (23DMB) and 2,2‐dimethylbutane (22DMB) isomers. The unique self‐adaptive framework of NCU‐542 selectively adsorbs 23DMB (RON = 101.7) while excluding 22DMB (RON = 91.8). Consequently, a record‐high adsorption capacity difference of 235.2 mg g −1 and an uptake ratio of 73.3 are achieved between 23DMB/22DMB. The diffusional time constant ( D ′, D / r 2 ) for 23DMB (1.03 × 10 −3 s −1 ) is 130‐fold higher than that of 22DMB (7.76 × 10 −6 s −1 ) and benchmark rigid JNU‐2 (6.5 × 10 −6 s −1 ). Furthermore, breakthrough experiments demonstrate the production of premium gasoline with a benchmark RON value of 99.2 from the equimolar mixture of n ‐hexane/2‐methylpentane/3‐methylpentane/23DMB/22DMB. Within the liquid system, 23DMB can be completely removed from 23DMB/22DMB solutions for five consecutive cycles under ambient conditions.