Selection of ionic liquids for the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures

Abstract

The separation of aromatic hydrocarbons (benzene, toluene, ethyl benzene and xylenes) from C 4 to C 10 aliphatic hydrocarbon mixtures is challenging since these hydrocarbons have boiling points in a close range and several combinations form azeotropes. In this work, we investigated the separation of toluene from heptane by extraction with ionic liquids. , are a factor of 1.5 -2.5 higher compared to those obtained with sulfolane (S tol/hept = 30.9, D tol = 0.31 at 40 -C), which is the most industrially used solvent for the extraction of aromatic hydrocarbons from a mixed aromatic/aliphatic hydrocarbon stream. From these five ionic liquids, [mebupy]BF 4 appeared to be the most suitable, because of a combination of a high toluene distribution coefficient (D tol = 0.44) and a high toluene/heptane selectivity (S tol/hept = 53.6). Therefore, with [mebupy]BF 4 also extraction experiments with other aromatic/aliphatic combinations (benzene/n-hexane, ethylbenzene/n-octane and m-xylene/n-octane) were carried out. The aromatic/aliphatic selectivities were all in the same range, from which it can be concluded that the toluene/heptane mixture is a representative model system for the aromatic/aliphatic separation. D

LLE data for the ionic liquid 3-methyl-N-butyl pyridinium dicyanamide with several aromatic and aliphatic hydrocarbons

“…The vessels were closed with a PVC-cover through which a stirrer shaft was lead. For each experiment 10 ml of the feed and 20 ml ionic liquid have been added and the mixture was stirred (1200 rpm) for 15 min to reach equilibrium [5]. After stirring, the two phases were allowed to settle for about 1 h. For phase mixing two stainless steel propellers, one in the bottom phase and one at the phase interface, with an electronic stirrer (Ika Eurostar) were used.…”

“…In order to maintain constant temperature (±0.1 K) a water bath (Julabo F32-MW) was used. A more detailed description of the experimental procedure was reported earlier by Meindersma et al [5].…”

“…The criteria, which a suitable ionic liquid for the separation of aromatic and aliphatic hydrocarbons must meet, are the same as for conventional solvents [3][4][5]. In general, this means high solubility for the aromatic hydrocarbons in the solvent combined with a high selectivity resulting from a low solubility of the aliphatic components.…”

Selective Solid-Phase Extraction of α-Tocopherol by Functionalized Ionic Liquid-modified Mesoporous SBA-15 Adsorbent

“…For example, the liquidliquid extraction of metal ions from water by ionic liquids containing metal-coordination agents and the separation of aromatics from alkanes by hydrophilic ionic liquids have been studied in detail. 36,37 However, solid adsorbents are highly advantageous for separation because of their ease of manipulation, the lack of limits on solvent miscibility and the lower consumption of volatile organic solvents. 38,39 Furthermore, the use of biphasic extraction systems requires the use of large amount of ionic liquids.…”

Highly Efficient Electrochemiluminescence of Functionalized Tris(2,2′‐bipyridyl)ruthenium(II) and Selective Concentration Enrichment of Its Coreactants

“…[12] Meindersma et al reported on the extraction of aromatic hydrocarbons from aromatic/aliphatic mixtures by selecting suitable ILs. [13] Electrochemiluminescence (ECL) is a means of converting electrical energy into radiative energy. It involves the production of reactive intermediates from stable precursors at the surface of an electrode via an applied voltage.…”