Related Experiment Video
Updated: Dec 6, 2025
08:25
Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs
Published on: January 17, 2020
7.6K
Crystal engineering of a rectangular sql coordination network to enable xylenes selectivity over ethylbenzene.
Naveen Kumar1, Shi-Qiang Wang1, Soumya Mukherjee1
1Department of Chemical Sciences , Bernal Institute , University of Limerick , Limerick V94 T9PX , Republic of Ireland .
Chemical Science
|October 9, 2020
Summary
A new coordination network, sql-1,3-Co-NCS, efficiently separates C8 aromatic isomers like xylenes from ethylbenzene. This sorbent shows high selectivity and capacity, offering an energy-efficient solution for chemical feedstock purification.
Area of Science:
- Materials Science
- Chemical Engineering
- Crystallography
Background:
- Separating C8 aromatic isomers (p-xylene, m-xylene, o-xylene, ethylbenzene) is crucial for chemical feedstocks but difficult due to similar properties.
- Physisorptive separation is a promising energy-efficient method, yet selective sorbents are scarce.
- Previous coordination networks showed promise but lacked broad selectivity or high capacity.
Purpose of the Study:
- To develop a novel mixed-linker coordination network for efficient C8 aromatic isomer separation.
- To investigate the sorption properties of the new material for both vapor and liquid phases.
- To understand the structural basis for the observed selectivity.
Main Methods:
- Crystal engineering was employed to synthesize a mixed-linker square lattice (sql) coordination network, denoted as sql-1,3-Co-NCS.
- The C8 vapor and liquid sorption properties of the synthesized material were systematically studied.
- Structural analysis, including stacking interactions, was performed to elucidate the separation mechanism.
Main Results:
- The sql-1,3-Co-NCS sorbent demonstrated high adsorption capacity from liquid xylenes (approximately 37 wt%).
- It is the first reported sorbent exhibiting high selectivity for each xylene isomer over ethylbenzene (selectivity > 5).
- Structural studies revealed favorable stacking interactions between the bptz linkers and xylene isomers, contributing to selectivity.
Conclusions:
- sql-1,3-Co-NCS represents a significant advancement in selective C8 aromatic isomer separation.
- This N-donor mixed-linker sql coordination network offers a new class of materials for energy-efficient separation processes.
- The findings pave the way for further exploration of understudied coordination networks in separation science.
Related Concept Videos
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.3K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.3K
01:18Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
2.5K
Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...
2.5K
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
3.6K
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
3.6K
01:28Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
4.5K
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.
4.5K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
15.8K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
15.8K
02:35Regioselectivity of Electrophilic Additions-Peroxide Effect
9.9K
In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
9.9K