A Dynamic Chemical Clip in Supramolecular Framework for Sorting Alkylaromatic Isomers using Thermodynamic and Kinetic Preferences

Abstract

Adsorptive chemical separation is at the forefront of future technologies,f or use in chemical and petrochemical industries.Inthis process,aporous adsorbent selectively allows asingle component from amixture of three or more chemical components to be adsorbed or permeate.T os eparate the unsorted chemicals,adifferent adsorbent is needed. Aunique adsorbent which can recognizea nd separate each of the chemicals from am ixture of three or more components is the necessity for the next generation porous materials.I nt his regard, we demonstrate a"dynamic chemical clip" in asupramolecular framework capable of thermodynamic and kineticsbased chemical separation. The dynamic space,f eaturing as trong preference for aromatic guests through p-p and C-H•••p interactions and adaptability,c an recognizet he individual chemical isomers from mixtures and separate those based on thermodynamic and kinetic factors.The liquid-phase selectivity and separation of the aromatic isomers are possible by the adaptability of the "chemical clip" and here we elucidate the prime factors in ac ombinatorial approach involving crystallographic evidence and detailed computational studies.

A gating ultramicroporous metal-organic framework showing high adsorption selectivity, capacity and rate for xylene separation

“…) and adsorption rates (need at least hours to reach equilibrium) [21,22,[27][28][29][30][31][32][33]. In this work, we show that alteration of the ligand arrangement in the classic MOFs can effectively change the connectivity of the pore system, giving not only gating narrow pores for high pX selectivity but also relatively large porosity for high pX capacity, as well as very fast adsorption kinetics.…”

“…After adsorption equilibrium, the pX selectivities were determined as 19, 221, and 46 (Figure 2a), meaning that pX with purity of 95.0%, 99.5%, and 95.5% could be produced after one adsorption-desorption cycle from equimolar pX/mX, pX/oX, and pX/mX/oX mixtures, respectively. Note that the pX/oX adsorption selectivity of MAF-89 is a new record [21,22,[27][28][29][30][31], and the pX/mX and pX/mX/oX adsorption selectivities are also among the highest (Table S3) [21,22,32,33]. Meanwhile, the pX selectivity for the three mixtures showed no obvious change from 1 to 720 min (Figure 2b and Figure S15), indicating negligible guest exchange like other ultramicroporous adsorbents dominated by kinetic separation mechanisms [17,30,32].…”

Tailoring a robust Al-MOF for trapping C2H6 and C2H2 towards efficient C2H4 purification from quaternary mixtures

“…To avail the preferential selectivity in MOFs, a few strategies have been generally adopted: (i) tuning the pore size/shapes, (ii) introducing functional organic linkers to generate strong binding sites, (iii) decorating the pore environment for favoured polarity and (iv) enhancing the density of open-metal sites (OMSs) for stronger interaction with unsaturated hydrocarbons. [25][26][27][28][29] MOFs with open-metal sites customarily adsorb C 2 H 4 over C 2 H 6 as a consequence of electrostatic interaction between the p-electrons of C 2 H 4 and the positively charged metal centres. [30][31][32][33] However, this process leads to the preferential adsorption of C 2 H 4 , and releases C 2 H 6 rst, while C 2 H 4 has to be recovered through heating or purging with an inert gas.…”

Adsorption Mechanism of Benzene Derivatives by Pagoda[n]arenes

“…The detection and management of benzene derivatives have become a focal point of research in supramolecular chemistry in recent years [16,42,43] . Pagoda[ n ]arenes, a novel category of macrocyclic hosts, offer a rigid molecular cavity and an abundant π‐electron environment, making them exceptionally suitable for benzene derivatives.…”