The research paper «Topologically guided tuning of Zr-MOF pore structures for highly selective separation of C6 alkane isomers» (doi: 10.1038/s41467-018-04152-5) has been issued in Nature Communications, a peer-reviewed open access journal published by the Nature Publishing Group.Topologically guided tuning of materials’ structure is an ambitious aim of scientists in the area of materials science and they have already begun to put it into practice. In particular, the research paper presents topological design and synthesis of three new Zr-MOF pore structures optimized for effective adsorptive separation of C6-alkane isomers. An important achievement of the present work, in Eugeny Alexandrov’s view, is the development of a scheme of structural regularities that provides the basis for predictions of new Zr-MOF pore structures with targeted properties.
Separation of hydrocarbons with relatively equal boiling temperatures is an important and complicated industrial process of gas and liquid fuel quantity improvement and purification of substances used in organic synthesis and production of polymers. Adsorptive separation serves as a low-cost, low energy input and more efficient alternative for energy intensive technology of distillation. MOFs have a great potential in adsorptive separation thanks to their high porosity and a wide choice of materials with suitable pore sizes. It provides a solid outlook for energy-efficient separation of hydrocarbons.
The team of contributors comprises scientists from research laboratories and universities of five countries: USA, Saudi Arabia, China, Russia and Italy. Hao Wang, Qibin Xia, Qining Wang, David H. Olson and Jing Li are from Rutgers University (США), Xinglong Dong and Yu Han represent King Abdullah University of Science and Technology (Saudi Arabia), Junzhong Lin and Junliang Sun - Peking University (China), Simon J. Teat - Lawrence Berkeley National Laboratory (USA), Stephanie Jensen and Timo Thonhauser - Wake Forest University (USA), Jeremy Cure, Kui Tan and Yves J. Chabal - University of Texas at Dallas (USA), scientific advisor of SCTMS Davide M. Proserpio from the University of Milan (Italy) and SCTMS senior research scientist Eugeny Alexandrov.
Applying ToposPro software package, the American scientists performed topological design and synthesis of new Zr-MOF pore structures optimized for effective adsorptive separation of C6-alkane isomers – a significant stage of oil refining for premium grade gasoline manufacture. The colleagues from Saudi Arabia tested separation properties of these two most stable materials conducting column breakthrough experiments. Interestingly, that MOF with the smallest pore size can uptake larger amount of n-hexane but excluding branched isomers. Its n-hexane uptake is 70% higher than that of a benchmark zeolite adsorbent. Selective adsorption mechanism through selective size sieving is confirmed through computational modeling. The compound 2 with larger pore size is capable of discriminating all three C6 isomers and yielding a high separation factor for 3-methylpentane over 2,3-dimethylbutane. This property is critical for producing gasoline with further improved quality. The scientists from the USA and PR China applied the methods of quantum-chemical modeling of C6 isomers molecules diffusion into MOFs to understand the causes of separation capacities of the studied materials. SCTMS scientists Prof. Davide M. Proserpio and Eugeny Alexandrov performed a detailed and vast topological analysis of Zr-MOFs (211 known structures).
«In our research work, thanks to developed scheme of structural regularities, - Eugeny Alexandrov comments, - we successfully apply theoretical methods of materials prediction in practice, but also provide the industry with the list of relevant materials that don’t exist yet, but can be obtained in the very near future”.