Browsing by Author "Horcajada, Patricia"
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- A complete separation of hexane isomers by a functionalized flexible metal organic frameworkPublication . Mendes, Patrícia A.P.; Horcajada, Patricia; Rives, Sébastien; Ren, Hong; Rodrigues, Alírio; Devic, Thomas; Magnier, Emmanuel; Trens, Philippe; Jobic, Hervé; Ollivier, Jacques; Maurin, Guillaume; Serre, Christian; Silva, José A.C.The separation ability of branched alkane isomers (nHEX, 3MP, 22DMB) of the flexible and functionalized microporous iron(III) dicarboxylate MIL-53(Fe)-(CF3)2 solid is evaluated through a combination of breakthrough experiments (binary or ternary mixtures), adsorption isotherms, X-ray diffraction temperature analysis, quasi-elastic neutron scattering measurements and molecular dynamics simulations. A kinetically controlled molecular sieve separation between the di-branched isomer of hexane 22DMB from a mixture of paraffins is achieved. The reported total separation between mono- and di-branched alkanes which was neither predicted nor observed so far in any class of porous solids is spectacular and paves the way towards a potential unprecedented upgrading of the RON of gasoline.
- Functionalization of metal-organic frameworks for hexane isomers separationPublication . Mendes, Patricia; Rodrigues, Alírio; Ragon, Florence; Horcajada, Patricia; Serre, Christian; Silva, José A.C.This work shows the effect of incorporating three different organic ligands (NH2-H2BDC, NO2-H2BDC and Br-H2BDC) into UIO-66(Zr) framework viewing the separation of hexane isomers(22DMB, 23DMB, 3MP and nHEX).
- Hexane isomers sorption on a functionalized metal-organic frameworkPublication . Silva, José A.C.; Mendes, Patricia; Ragon, Florence; Rodrigues, Alírio; Horcajada, Patricia; Serre, ChristianA series of functionalized porous Zr terephthalate MOFs of the UiO-66(Zr) structure type bearing either Br, NH2 or NO2 groups have been synthesized at the multi-gram scale through an atmospheric pressure solvothermal route with the final aim of investigating the influence of functionalization on the separation of hexane isomers (22DMB, 23DMB, 3MP and nHEX). The studies performed in a fixed bed adsorption column with equimolar mixtures at temperatures between 343 and 423 K and partial pressure up to 10 kPa have shown that the Br, NO2 and NH3 forms exhibit an uptake reaching 15%, being the sorption selectivity hierarchy on the whole comparable to the bared UiO-66 solid: 22DMB approximate to 23DMB >> 3MP nHEX. The 22DMB/nHEX selectivity reaches approximately three at low uptake while the 22DMB/3MP selectivity of UiO-66_NO2 is nearly constant (1.3).
- Multicomponent hexane isomers sorption on MOF ZIF-8Publication . Mendes, Patricia; Silva, José A.C.; Rodrigues, Alírio; Horcajada, Patricia; Serre, ChristianThe main goal of this research focuses on the development of an adsorptive process to separate hexane isomers (kinetic diameter very similar) in order to improve the quality of gasoline measured by the octane number (RON). In this investigation, studies of sorption equilibrium of hexane isomers: n-hexane (RON 25), 3-methylpentane (RON 75), 2,3-dimethylbutane (RON 103) and 2,2-dimethylbutane (RON 94) were performed on ZIF-8. The MOF ZIF-8 was synthesized and fully characterized by XRD, TGA, IR and surface area at the Institute Lavoisier Versailles.
- Separation of hexane isomers on rigid porous metal carboxylate-based metal-organic frameworksPublication . Mendes, Patricia; Rodrigues, Alírio; Horcajada, Patricia; Eubank, Jarrod; Devic, Thomas; Serre, Christian; Silva, José A.C.Screening separation studies with equimolar quaternary mixtures of hexane isomers, namely, n-hexane/3-methylpentane/2,3-dimethylbutane/2,2- dimethylbutane (n-HEX/3MP/23DMB/22DMB), in the temperature range of 343–423 K and partial pressures up to 10 kPa have been performed using three rigid porous metal (III/IV) carboxylate-based metal–organic frameworks (MOFs) with different composition and topology. These carboxylate-based MOFs are denoted as MIL-100(Cr), MIL-125(Ti)-NH2 and MIL-127(Fe). Adsorption study results revealed that all the isomers were adsorbed on MIL-100(Cr) and MIL-125(Ti)-NH2, with adsorption amounts reaching 24 and 12 wt%, respectively, and the order of adsorption being similar to the normal boiling point of the compounds, that is, n-HEX > 3MP > 23DMB > 22DMB, with selectivity of adsorption never exceeding three (i.e. selectivities between the extreme compounds n-HEX and 22DMB). It is worth noting that adsorption of branched isomers is practically excluded on MIL-127(Fe), which exhibits a strong molecular sieve effect of the adsorbed n-HEX with the loading capacity reaching a maximum of 7 wt%. Finally, an alternative strategy, which involved probing the effect of post-synthetic functionalization on the coordinatively unsaturated metal sites of the MIL-100(Cr) using functional group ethylamine or N-methylethylenediamine showed no significant differenc
- Single and multicomponent adsorption of hexane isomers in the microporous ZIF-8Publication . Mendes, Patrícia A.P.; Rodrigues, Alírio; Horcajada, Patricia; Serre, Christian; Silva, José A.C.Single, binary and ternary breakthrough experiments of hexane (C6) isomers n-hexane (nHEX), 3-methylpentane(3MP), and 2,2-dimethylbutane (22DMB) were performed in the microporous zinc methyl-imidazolate metal–organic framework ZIF-8, covering the temperature range between 313 and 423 K and partial pressures up to 20 kPa. Adsorption equilibrium isotherms for nHEX were collected from single component breakthrough experiments who show that the sorption behavior of linear nHEX is totally different than the one observed for the branched isomers. Indeed, while nHEX is retained in the bed the branched paraffins spontaneously breakthrough leading to an efficient separation with a remarkable working capacity (25 wt%) for nHEX at 313 K and partial pressure 10 kPa. Langmuir isotherm is found to reasonably describe the adsorption equilibrium data of nHEX while the heat of sorption reaches 32.8 kJ/mol with Langmuir equilibrium affinity constants ranging from 1.73 to 0.0624 kPa 1 between 313 and 423 K, respectively. The ternary experiments (nHEX/3MP/22DMB) show a complete separation between nHEX and the branched isomers together with an adsorbed amount of nHEX similar to the one found in single component experiments. In the binary experiments (3MP/22DMB) the separation and sorption capacity is negligible. A fixed bed adsorption dynamic model is used to demonstrate that the complete separation of nHEX from the branched paraffins is due to a spontaneous breakthrough ofthe branched paraffins due to its lower diffusivity values when compared with nHEX.