Styrene Purification by Guest-Induced Restructuring of Pillar[6]arene

Abstract

The separation of styrene (St) and ethylbenzene (EB) mixtures is important in the chemical industry. Here, we explore the St and EB adsorption selectivity of two pillar-shaped macrocyclic pillar[n]arenes (EtP5 and EtP6; n = 5 and 6). Both crystalline and amorphous EtP6 can capture St from a St-EB mixture with remarkably high selectivity. We show that EtP6 can be used to separate St from a 50:50 v/v St:EB mixture, yielding in a single adsorption cycle St with a purity of >99%. Single-crystal structures, powder X-ray diffraction patterns, and molecular simulations all suggest that this selectivity is due to a guest-induced structural change in EtP6 rather than a simple cavity/pore size effect. This restructuring means that the material “self-heals” upon each recrystallization, and St separation can be carried out over multiple cycles with no loss of performance.

Separation of Linear and Branched Alkanes Using Host–Guest Complexation of Cyclic and Branched Alkane Vapors by Crystal State Pillar[6]arene

“…[10] Huang,C ooper, and co-workers reported styrene purification using activated crystals of pillar [6]arene. [11] Our group reported gas and organic vapor uptake using activated crystals of pillar [6]arene with 12 phenolic moieties. [12] We also showed that activated pillar [5]arene crystals can be used for uptake and sensing of linear alkane vapors, [9,13] and separation of linear alkanes with various lengths.…”

Applications of Pillar[n]arene‐Based Supramolecular Assemblies

“…of isooctane (b.p. [31] Separation of these two compounds using conventional distillation is also difficult because of the small difference in b.p. : 98 8 8C), therefore, the separation of these two alkanes via distillation is very difficult.…”

Supramolekulare Pillar[n]aren‐Aggregate und ihre Anwendungen

“…Aktivierte Pillar [6] [31] Die Tr ennung dieser beiden Verbindungen über eine konventionelle Destillation ist wegen des geringen Siedepunktunterschieds (9 8 8C) ebenfalls schwierig.D as Dampfaufnahmeverhalten der aktivierten H16-Kristalle wurde durch Behandlung der Kristalle mit einer 1:1-Dampfmischung von Styrol und Ethylbenzol untersucht. Nach sechsstündiger Exposition der H16-Kristalle gegenüber einer 1:1-Mischung und anschließendem Erhitzen zur Desorption des in den H16-Kristallen verkapselten Styrols konnte Styrol mit über 99 %R einheit gewonnen werden.…”