Effective Separation and Purification of Nitrogen-Containing Aromatics from the Light Portion of a High-Temperature Coal Tar Using Choline Chloride and Malonic Acid: Experimental and Molecular Dynamics Simulation

Abstract

An effective deep eutectic solvent (DES) combined with column chromatography was designed for separating nitrogen-containing aromatics (NCAs) from the light portion (LP, which is petroleum ether-extractable portion) of a high-temperature coal tar. The total content of NCAs enriched with equimolar choline chloride (CC)/malonic acid mixture is much higher than that with other CC-based DESs. The maximum total recovery of NCAs is 57.2% with 1:2 of DES/LP mass ratio from the third run of extracting LP at 35 °C. The relative contents of carbazole, benzo­[h]­quinoline, and quinoline enriched by flash preparative chromatography are 93.3, 92.0, and 90.4%, respectively. In addition, the nonbonded interaction energy among the DESs, NCAs, and condensed arenes was calculated for demonstrating the difference in extract yield with diverse DESs. The reduced density gradient method proved that the typical hydrogen bonds, X–H···π bonds (X denotes >C, >N, or −O), and van der Waals forces widely exist among the DESs and NCAs through molecular dynamics simulations.

Effective Separation of Condensed Arenes from High-Temperature Coal Tar and Insight into Related Intermolecular Interactions

“…The representative snapshot can visually describe the distribution of each molecule in the system. 27,37 38 In Figure 6, PE−CAs share the same NBIAE type in which X− H•••π bond plays an important role. 39,40 The intensity of the interaction energy can be sorted as: PE−pyrene > PE− fluoranthene > PE−phenanthrene > PE−naphthalene.…”

“…As illustrated in Figure , the cubic space was used as the boundary of the binary system PE–CAs and the change of the color distinguished different molecules. The representative snapshot can visually describe the distribution of each molecule in the system. , …”

Computer Simulations of Deep Eutectic Solvents: Challenges, Solutions, and Perspectives

“…Parameters are given DES on the metal surface [ 318 ] 60 ChCl:Levulinic acid (1:2) No name of FF. Parameters are given DES for CO 2 capture [ 52 ] 61 ChCl:Malonic acid ChCl:Oxalic acid ChCl:Succinic acid ChCl:Fumaric acid Different molar ratios GAFF/no corrections Investigation of DES structure [ 221 ] 62 ChCl:Malonic acid (1:1, 1:2) GAFF/no corrections Separation of nitrogen-containing aromatics by DES [ 384 ] 63 ChCl:Oxalic acid (1:1) CHARMM 36/no corrections Biomass separation [ 341 ] 64 ChCl:Phenyl propionic acid (1:2) CHARMM 36/charges scaling is 0.8. Investigation of DES structure [ 224 ] 65 ChCl:Phenyl propionic acid Different molar ratios CHARMM 36/no corrections Investigation of DES structure [ 223 ] 66 ChCl:Phenylacetic acid (1:2) No name of FF.…”

Intermolecular Interaction and Extraction Explorations for Separation of High-Boiling Neutral Nitrogen Compounds Using Biodegradable Ionic Liquids

“…Because of the complex composition of anthracene and wash oil, , it is difficult to test the extraction ability of the biodegradable TMG-based ILs with real anthracene and wash oil. From the literature, − carbazole and indole were selected as the typical HBNNC, and n -heptane and toluene were used to prepare a solvent.…”