Yuefeng Deng

Application of Choline Chloride·xZnCl2 Ionic Liquids for Preparation of Biodiesel

Abstract The inexpensive and moisture-stable Lewis-acidic ionic liquids were prepared and applied for transesterification of soybean oil to biodiesel. The influences of molar ratio of methanol to soybean oil, reaction temperature and amount of ionic liquids were investigated. The transesterification of soybean oil to biodiesel catalyzed by choline chloride· x ZnCl 2 ionic liquids showed many advantages such as mild conditions and lower cost. On the other hand, the non-ideal yield and complicated separation between biodiesel and soybean oil were also investigated and analyzed. The improvement on the systems of choline chloride· x ZnCl 2 was proposed for further investigation.

Adsorption of phenol from water by N-butylimidazolium functionalized strongly basic anion exchange resin

N-butylimidazolium functionalized strongly basic anion exchange resin with Cl(-) anion (MCl) was prepared by anchoring N-butylimidazole onto chloromethylated macroporous styrene-divinylbenzene (St-DVB) copolymer. The adsorption performances of phenol on MCl were studied using the batch technique at acidic and alkaline pH. The studies showed that phenol can be effectively removed at both acidic and alkaline pH. The maximum adsorption was achieved at about pH 11. The maximum adsorption capacities of phenol on MCl at pH 6.6 and 11.2 were 80.2 and 92.9 mg/g, respectively. The adsorption mechanism was mainly molecular adsorption at acidic pH and anion exchange at alkaline pH. The adsorption of phenol was hindered by the presence of Cl(-) and SO(4)(2-) at alkaline pH due to the competitive anion exchange reaction. The adsorption of molecular phenol species on MCl at acidic pH was exothermic, and the anion exchange of phenolate species by MCl at alkaline pH was endothermic. Desorption of phenol from loaded adsorbent was achieved by using 0.5 mol/L NaOH and 0.5 mol/L NaCl mixed solution. MCl can simultaneously remove phenol and Cr(VI) from their mixtures, which would be of practical value in actual industrial wastewater treatment.

Extraction mechanism of cerium(IV) in H2SO4/H3PO4 system using bifunctional ionic liquid extractants

The extraction of Ce(IV) in H2SO4/H3PO4 system was investigated systematically using bifunctional ionic liquid extractants (Bif-ILES) [A336][P507], [A336][P204] and [A336][C272] in n-heptane. The effects of H2SO4 concentration, extractant concentration and salting-out agent concentration were observed in detail. The extraction mechanism of Ce(IV) in H2SO4/H3PO4 system was obtained. The comparison with other extractants such as Cyanex923, TBP was also studied. Thermodynamic functions of the extraction reaction were calculated, showing that the extraction was an exothermic process. The separation of Ce(IV) from RE(III) and Th(IV) was also investigated. The result indicated that Ce(IV) could be selectively extracted in this system. CePO4 nanoparticles were obtained in the process of stripping using H2O2 in H2SO4/H3PO4 system. X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectroscopy were adopted for the characterization of the sample.

Application of Porous N-Methylimidazolium Strongly Basic Anion Exchange Resins on Cr(VI) Adsorption from Electroplating Wastewater

The porous N-methylimidazolium functionalized strongly basic anion exchange resins (PCl) were synthesized, characterized and applied for Cr(VI) adsorption from electroplating wastewater. FT-IR and elemental analysis of PCl were used to characterize the structure and the content of functional groups of PCl. The bath model results show that the adsorption capacities of PCl for Cr(VI) are above 139 mg g−1 at pH range 2.0–5.0, and the Cr(VI) can be easily desorbed with the mixture solution of 0.2 mol L−1 NaOH + 0.2 mol L−1 NaCl. PCl resins with precipitation technologies were successfully used for the separation and recovery of toxic Cr(VI), and co-existing Cr(III), Fe(III), Cu(II), Zn(II), Ni(II), and Al(III) heavy metals from electroplating wastewater in the bench scale. Cr(VI) was separated and precipitated as value industrial product BaCrO4 with purity higher than 99%. The recovery yields of other heavy metals are more than 99% within the optimum pH values range from 8.0 to 9.0. After the treatment of the wastewater using PCl-based high efficient, economical and clean technique, the concentrations of total Cr, Cr(VI) and other heavy metals in water are less than the national emission standard.

Enrichment of Aromatic Compounds Using Ionic Liquid and Ionic Liquid-Based Aqueous Biphasic Systems

Both hydrophibic [C8mim][PF6] and [C4mim]Cl/(K2CO3, K2HPO4 or K3PO4) aqueous biphasic system (ABS) were employed for the enrichment of aromatic compounds including nitrobenzene, 4-nitrophenol, phenol and aniline from aqueous solutions. In [C8mim][PF6] enrichment system, the distribution ratio (D) of nitrobenzene and aniline increase with the increasing of pH values of aqueous phase from 2 to 8, but there is no obvious change for 4-nitrophenol and phenol. And the D values of the aromatic compounds decrease with the phase ratio change from 1/5 to 1/30 (IL phase volume/aqueous phase volume). In [C4mim]Cl/(K2CO3, K2HPO4 or K3PO4), the distribution ratio increase with the increasing of the salts concentrations. The distribution ratio order in [C8mim][PF6] and [C4mim]Cl/kosmotropic salt ABS is nitrobenzene > phenol > aniline > 4-nitrophenol. It is expected that these results are promising for the removal of the aromatic compounds from water, especially for sample enrichment in analytical science.

Separation of ternary systems of hydrophilic ionic liquid with miscible organic compounds by RPLC with refractive index detection

A rapid and simple analytical method was developed for the simultaneous and quantitative determination and separation of hydrophilic imidazolium ionic liquids (ILs) (1-butyl-3-methylimidazolium chloride, [C(4)mim]Cl; 1-hexyl-3-methylimidazolium chloride, [C(6)mim]Cl; 1-octyl-3-methylimidazolium chloride, [C(8)mim]Cl; 1-allyl-3-methylimidazolium chloride, [Amim]Cl; or 1-allyl-3-methylimidazolium bromide, [Amim]Br) with miscible ethyl acetate and EtOH and their mixtures using reverse phase liquid chromatography coupled with refractive index detection (RPLC-RI). The influence of 60 to 100% (volume percentage) methanol in the mobile phase on the IL systems ([C(4)mim]Cl, [C(6)mim]Cl, [C(8)mim]Cl, [Amim]Br, or [Amim]Cl)-ethyl acetate-EtOH was investigated. The optimum mobile phase for the system [C(8)mim]Cl-ethyl acetate-EtOH, [C(4)mim]Cl-ethyl acetate-EtOH, [Amim]Br-ethyl acetate-EtOH and [Amim]Cl-ethyl acetate-EtOH was methanol/water (60:40, v/v), and methanol/water (70:30, v/v) for [C(6)mim]Cl-ethyl acetate-EtOH. Under optimum mobile phase conditions for each system, the RSD of the retention time ranged from 0.02 to 0.04%, and the RSDs of the peak area percent ranged from 0.23 to 1.85%, which showed good reproducibility of the RPLC-RI method. The RPLC-RI method can determine IL, ethyl acetate, and EtOH simultaneously in 5 min, and the analytes, especially IL, can be eluted completely. The results show that the RPLC-RI method can be used to separate and determine ILs in mixtures with organic compounds simultaneously and quantitatively.

Ionic liquids as novel spectroscopic solvents for Eu(III)-containing complex

Novel soft materials, Eu(III)-containing complex dissolved in [C(8)mim][X] (X=Cl(-), PF(6)(-) and Tf(2)N(-)) ionic liquids, were synthesized. FT-IR and elementary analysis of complex proved that the molecular formula is [C(8)mim][Eu(TTA)(4)]. The complex and ionic liquids had high thermal stability according to TGA. The photoluminescence spectra showed that the [C8mim][Eu(TTA) 4] exhibited typical red emission deriving from (5)D(0)-(7)F(2) transition. After dissolving the complex in [C(8)mim][X] (X=Cl(-), PF(6)(-) and Tf(2)N(-)) ionic liquids, the luminescence intensity decreased in the following order: [C(8)mim][Tf(2)N]approximate to[C(8)mim][PF(6)]>[C(8)mim][Cl]. This was because Tf(2)N(-) and PF(6)(-) anions had larger molecular volume and weaker coordination ability than Cl(-).

Applying Aqueous Biphasic Systems for Partitioning N-Methylimidazolium Grafted Merrifield Resin Microparticles

Abstract The partition behavior of Merrifield resin and two derivatives, RCl and RPF6, has been investigated in a variety of aqueous biphasic systems (ABS). The composition of ABS, different anions of the resins, and the graft ratio were found to be important for controlling the partition behavior of Merrifield resin, RCl, and RPF6 in three types of ABS: PEG-4000/Dextran-20000, PEG-4000/K2CO3, and C4mimCl/K2CO3. It was found that a 10.86% graft ratio of RCl showed a satisfactory separation for the Merrifield resins and N-methylimidazolium grafted Merrifield resins in PEG-4000/Dextran-20000 ABS. It was speculated that RCl or RPF6 has a strong interaction with Dextan-20000 and [C4mim]Cl, but very weak interaction with PEG-4000. Therefore, it was likely that the N-methylimidazolium grafted Merrifield resin was partitioned to the bottom Dextran-rich phase.