Zeolitic Imidazolate Framework-8 Nanocrystal Coated Capillary for Molecular Sieving of Branched Alkanes from Linear Alkanes along with High-Resolution Chromatographic Separation of Linear Alkanes

Abstract

A zeolitic imidazolate framework-8 (ZIF-8) nanocrystal coated capillary is shown not only to have a strong ability to sieve branched alkanes from linear alkane isomers owing to the narrow pore windows but also to offer excellent features for high-resolution gas chromatographic separation of linear alkanes due to van der Waals interaction between linear alkanes and the hydrophobic inner surfaces of the micropores. This makes the ZIF-8 coated capillary very promising for the specific adsorption and separation of alkanes in complicated matrices.

Crystal formation and size control of zeolitic imidazolate frameworks with mixed imidazolate linkers

“…For example, the structure of ZIF-8 was retained in boiling benzene, methanol and water for several days [2]. The great capacities of ZIFs to adsorb, store and separate gases [4] as well as hydrocarbons [5] have made them promising candidates as molecular sieves [6][7][8], films [9] and membranes [10][11][12][13]. ZIFs have for example high affinity for CO 2 [14].…”

Metal–organic framework growth at functional interfaces: thin films and composites for diverse applications

“…The same group have also used the same dynamic coating method to prepare capillary columns of ZIF-8 for the separation of mixtures of linear and branched alkanes. 89 The small pore size 15 (3.4 Å), sodalite cage structure and hydrophobic surface of ZIF-8 make this ideal for this application, and linear C6 and C8 alkanes are effectively separated from their branched isomers with baseline resolution. Branched alkanes are found to elute much earlier than their 20 linear counterparts on the ZIF-8 column, and do not follow the usual trend of elution which tends to follow the order of boiling points.…”

“…The 30 elution order observed for linear and branched alkanes fits with adsorption enthalpies calculated from van't Hoff plots. 89 Although branched alkanes are not particularly well separated from each other, the ZIF-8 columns do display high resolution and selectivity for the separation of mixtures of linear alkanes 35 covering a broad range of boiling points, with the elution sequence following the order of boiling points. This selectivity arises due to van der Waals interactions between the alkanes and the hydrophobic inner surface of the ZIF-8 micropores.…”

An Organophilic Pervaporation Membrane Derived from Metal–Organic Framework Nanoparticles for Efficient Recovery of Bio‐Alcohols

“…[5] One particularly interesting member of this family is ZIF-8 (with the formula zinc(2-methylimidazolate) 2 ). [6] ZIF-8 represents an appropriate model system and has found many applications, including selective adsorption, [7] membrane-based separation, [3a,b,g,i, 4a-c] chromatography, [8] catalysis, [9] and as a sensor. [10] In contrast to the hydrothermal synthesis of nanozeolites (e.g.…”