Browsing by Author "Maity, Tanmoy"
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- Hexane isomers separation on an isoreticular series of microporous Zr carboxylate metal organic frameworksPublication . Henrique, Adriano; Maity, Tanmoy; Zhao, Hengli; Brântuas, Pedro; Rodrigues, Alírio; Nouar, Farid; Ghoufi, Aziz; Maurin, Guillaume; Silva, José A.C.; Serre, ChristianA series of isoreticular Zr carboxylate MOFs, MIL-140A, B and C, exhibiting 1D microporous triangular shaped channels and based on different aromatic dicarboxylate ligands (1,4-BDC, 2,6-NDC and 4,4′-BPDC, respectively), were investigated by chromatographic breakthrough experiments regarding their ability to separate hexane isomers (nC6/2MP/3MP/23DMB/22DMB). Both single and equimolar multicomponent experiments were performed at the temperatures 343, 373, and 423 K and a total hydrocarbon pressure up to 50.0 kPa using the MIL-140B form. The elution order is similar to that of the normal boiling point of the compounds nC6 > 2MP > 3MP > 23DMB > 22DMB. It is noteworthy that this material enables separation of the hexane isomers by class, linear > mono-branched > di-branched, with a selectivity (linear + mono-branched isomers/di-branched isomers) up to 10 at 343 K, decreasing, however, as the temperature increases. Grand canonical Monte Carlo simulations were further performed to gain insight into the adsorption/separation mechanisms, highlighting the crucial need to consider a tiny tilting of the organic linkers for capturing the experimental observations. The impact of the pore size was finally assessed through the comparison with MIL-140A and MIL-140C, respectively, based on multicomponent experiments at 343 K. We evidenced a significant decrease of the selectivity (about 2) in both cases while the loadings were decreased or increased for MIL-140A and MIL-140C, respectively. Additionally, MIL-140C was demonstrated to exhibit an uncommon shift in the elution order occurring between nC6 and 3MP, 3MP being the last compound to saturate in the column.
- Separation of branched alkanes feeds by a synergistic action of zeolite and metal-organic frameworkPublication . Brântuas, Pedro; Henrique, Adriano; Wahiduzzaman, Mohammad; Wedelstedt, Alexander von; Maity, Tanmoy; Rodrigues, Alírio; Nouar, Farid; Lee, U-Hwang; Cho, Kyung Ho; Silva, José A.C.; Serre, Christian; Maurin, GuillaumeZeolites and metal-organic frameworks (MOFs) are considered as “competitors” for new separation processes. The production of high-quality gasoline is currently achieved through the total isomerization process that separates pentane and hexane isomers while not reaching the ultimate goal of a research octane number (RON) higher than 92. This work demonstrates how a synergistic action of the zeolite 5A and the MIL-160(Al) MOF leads to a novel adsorptive process for octane upgrading of gasoline through an efficient separation of isomers. This innovative mixed-bed adsorbent strategy encompasses a thermodynamically driven separation of hexane isomers according to the degree of branching by MIL-160(Al) coupled to a steric rejection of linear isomers by the molecular sieve zeolite 5A. Their adsorptive separation ability is further evaluated under real conditions by sorption breakthrough and continuous cyclic experiments with a mixed bed of shaped adsorbents. Remarkably, at the industrially relevant temperature of 423 K, an ideal sorption hierarchy of low RON over high RON alkanes is achieved, i.e., n-hexane ≫n-pentane ≫2-methylpentane > 3-methylpentane⋙ 2,3-dimethylbutane > isopentane ≈ 2,2-dimethylbutane, together with a productivity of 1.14 mol dm−3 and a high RON of 92, which is a leap-forward compared with existing processes.