Separation of Organic Nitrogen Compounds by Supported Liquid Membranes Based on Ionic Liquids

Abstract

Heterocyclic compounds including nitrogen (quinoline, isoquinoline, and pyridine) were separated from n-heptane mixtures through supported liquid membranes using room temperature ionic liquids, based on 1-alkyl-3-methylimidazolium and quaternary ammonium salts. The organic nitrogen compounds selectively permeated the membranes. The differences in the structures of room temperature ionic liquids had little effect on the permeability of organic nitrogen compounds. Liquid membranes that used more hydrophilic room temperature ionic liquids yielded higher selectivity. Lower pyridine concentration and temperature caused increases in selectivity. Application of supported liquid membranes based on ionic liquids has potential for the separation process of organic nitrogen compounds and heptane.

Effects of Ionic Liquids and Supports on the Permeation of Organic Nitrogen Compounds through Supported Ionic Liquid Membranes

“…Table 3 and 4 show the permeation coefficient and selectivity for quinoline and pyridine, respectively, using hydrophilic PVDF. In both Tables, the permeation coefficients of quinoline, pyridine and heptane increased and selectivity decreased with increasing hydrophobicity (alkyl-chain length) of the imidazolium cation, as described in a previous paper [9]. In contrast, an increase in the hydrophobicity of the anion (PF 6 > Br > Cl, [15]) caused a decrease in the permeation coefficients of quinoline, pyridine and heptane.…”

“…Figure 3 shows typical results of the concentration change of quinoline and heptane in the receiving phase using [C 4 mim][Br] and polypropylene. As reported previously [9], quinoline selectively permeates against heptane based on the solution-diffusion mechanism. From the increase in the concentration in the receiving phase, C R , the permeation coefficient, P, was calculated from the following equation under the condition of equal volumes of both feed and receiving phases [14].…”

“…Methods based on solvent extraction have been proposed [4,5] with the advantages of low energy cost, elimination of hydrogen usage, retention of the chemical structures of the fuels, and no special equipment requirements [5]. Recently, desulfurization and denitrogenation have been investigated with solvent extraction [6][7][8] and supported liquid membranes (SLM) [9,10] using ionic liquids.…”

“…19, 147 -152 (2012) -Notes -liquid membranes that used more hydrophilic ionic liquids yielded higher selectivity. [9,10]. In these papers, we examined these effects by using the hexafluorophosphates of 1-alkyl-3-methyl imidazolium.…”

Evaluation of nitrogen effect on ultrasound-assisted oxidative desulfurization process

“…Due to this limitation, some nonconventional processes for nitrogen removal have been proposed, resulting in better efficiency. Some of these processes are based on the use of microbiological denitrogenation [16][17][18], ionic-liquids [19], selective adsorption [20,21] and oxidative denitrogenation (ODN) [22,23].…”