Hydroxylation of Benzene to Phenol via Hydrogen Peroxide in Hydrophilic Triethylammonium Acetate Ionic Liquid

A new Fenton-like system in a medium of hydrophilic triethylammonium type of ionic liquid(IL) was used for the hydroxylation of benzene to phenol. The triethylammonium acetate([Et3NH][CH3COO]) IL exhibited retardation performance for the decomposition of H2O2 and protection performance for the further oxidation of phenol, thus the yield and selectivity to phenol were promoted greatly. The acidity of the system was proved to be an important factor for the selectivity to phenol. The utilization of H2O2 and th...     

Interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids with glucose in water: a study of volumetric properties, viscosity, conductivity and NMR

Extensive applications of ionic liquids (ILs) may result in their accumulation in the ecological environment and organisms. Although ILs are popularly called "green solvents", their toxicity, in fact, has been exhibited. Therefore the interaction of ILs with biomolecules is a cutting-edge research subject. Herein, the interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids ([C(4)mim][HCOO], [C(4)mim][CH(3)COO] and [C(4)mim][CH(3)CH(2)COO]) with glucose in water were studied for their volumetric properties, viscosity, conductivity and NMR spectra. Limiting apparent molar volumes (V(Φ, IL)(0)), viscosity B-coefficients, limiting molar conductivities (Λ(0)) and Walden products (Λ(0)η(0)) were evaluated for the ILs in glucose + water solutions. Volumetric interaction parameters were also obtained from the transfer volumes of the ionic liquids. The contributions of the solvent properties (B(1)) and the ionic liquid-solvent interactions (B(2)) to the B-coefficient were extracted, together with molar activation energies (Δμ(IL)(0≠)) of the ionic liquids for viscous flow of the aqueous glucose + IL solution. In addition, the (13)C and (1)H NMR spectra of methyl β-D-glucopyranoside and ILs in β-D-glucopyranoside + IL + D(2)O were studied. The NMR results show that no special and strong interactions were observed between glucopyranoside and the ILs. However, it was confirmed that the H2 on the imidazolium ring has more activity (acidity) than atoms H4 and H5. The macro-properties and their changes were also discussed in terms of the size, structure and solvation of the ILs and glucose.     

Non‐Ideal Mixing Behaviour of Hydrogen Bonding in Mixtures of Protic Ionic Liquids

Ionic liquids (ILs) attract interest in science and technology as a result of their unique properties. Binary and ternary mixtures of ILs significantly increase the number of possible cation/anion combinations, resulting in targeted physical and chemical properties. In this work, we study the mixing behaviour of two protic ILs: triethyl ammonium methylsulfonate [Et₃NH][CH₃SO₃] and triethylammonium triflate [Et₃NH][CF₃SO₃]. We find a characteristic deviation from ideal mixing by means of low‐frequency infrared spectroscopy. By using molecular dynamics simulations, we explain this behaviour as being the result of different strengths of anion/cation hydrogen bonding. This non‐ideality of non‐random H‐bond mixing is also reflected in macroscopic properties such as the viscosity. Mixing suitable ILs may, thus, result in new ILs with targeted physical properties.     

Solution and solid-state preparation of 18-crown[6] complexes with M[HSO4]n salts (M = NH4+, K+, Sr2+ and n = 1, 2) and an investigation of solvation/desolvation processes and crystal polymorphism

18-Crown[6] ether has been used to prepare a new class of organic-inorganic complexes of general formula 18-crown[6]M[HSO(4)](n) (where M = NH(4) (+), K(+), Sr(2+) and n = 1, 2) by reacting directly in solution or in the solid state the crown ether 18-crown[6] with inorganic salts such as [NH(4)][HSO(4)], K[HSO(4)], and Sr[HSO(4)](2). The structures of 18-crown[6][NH(4)][HSO(4)]2 H(2)O (12 H(2)O), 18-crown[6][NH(4)][HSO(4)] (1), 18-crown[6]K[HSO(4)]2 H(2)O (22 H(2)O), 18-crown[6]K[HSO(4)] (2), and 18-crown[6]Sr[HSO(4)](2) (3) have been characterized by single-crystal X-ray diffraction. The reversible water loss in compounds 12 H(2)O and 22 H(2)O leads to formation of the corresponding anhydrous phases 18-crown[6][NH(4)][HSO(4)] (1), and 18-crown[6]K[HSO(4)] (2), which undergo, on further heating, enantiotropic solid-solid transitions very likely associated with the on-set of a solid state dynamical process. Similar high-temperature behavior is shown by 18-crown[6]Sr[HSO(4)](2) (3). The dehydration and phase-transition processes have been investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and variable temperature X-ray powder diffraction.     

Thermodynamic characterization of the osmolyte effect on protein stability and the effect of GdnHCl on the protein denatured state

To understand the biomolecular interactions of osmolytes or guanidine hydrochloride (GdnHCl) with protein functional groups, we have determined the apparent transfer free energies (Delta'(tr)) of a homologous series of cyclic dipeptides (CDs) from water to aqueous solutions of osmolytes or GdnHCl through solubility measurements, as a function of osmolyte or GdnHCl concentration at 25 degrees C under atmospheric pressure. The materials investigated in the present study included the CDs of cyclo(Gly-Gly), cyclo(Ala-Gly), cyclo(Ala-Ala), cyclo(Leu-Ala), and cyclo(Val-Val), the osmolytes of trimethylamine N-oxide (TMAO), sarcosine, betaine, proline, and sucrose, and the denaturant of GdnHCl. We observed positive values of (Delta'(tr)) for CDs from water to osmolyte, indicating that interactions between osmolytes and CDs are unfavorable. In contrast, negative (Delta'(tr)) contributions were observed for CDs from water to GdnHCl, revealing that favorable interactions are predominant. The experimental results were further used to estimate the transfer free energies (Delta'(tr)) of the peptide bond (-CONH-), the peptide backbone unit (-CH2C=ONH-), and various functional groups from water to aqueous solutions of osmolyte or GdnHCl.     

Copolymers dispersions designed to shaping of ceramic materials

Journal of Thermal Analysis and Calorimetry - To study the effect of ionic liquids (ILs) of the microstructure on the surface of the coal, four ILs ([Emim][BF4], [Bmim][BF4], [Bmim][NO3], and...     

A metallacage encapsulating chloride as a probe for a solvation scale in ionic liquids

With the purpose of assessing the reactivity of chloride ions dissolved in ionic liquids (ILs), a relative scale for the solvation of chloride is given for a series of ILs based on the bis(trifluoromethane)sulfonimide ([Tf(2)N]) anion and different cations, 1-butyl-3-methylimidazolium ([bmim]), 1-butyl-2,3-dimethylimidazolium ([bdmim]), 1-butyl-1-methylpyrrolidinium ([bmpy]), 1-butylpyridinium ([bpy]), 1-pentyl-1,1,1-triethylammonium ([C(5)e(3)am]), and 1-(2-hydroxy)ethyl-3-methylimidazolium ([mimeOH]). Insights into the solvation of chloride are achieved by the thermodynamic study of the reaction of dissociation of a chloride-templated nickel(II) metallacage performed at various temperatures by UV-visible spectroscopy in each IL. The order of chloride solvation [C(5)e(3)am][Tf(2)N] < [bmpy][Tf(2)N] < [bmim][Tf(2)N] 相似文献   

Study of Imidazolium Ionic Liquids:Temperature-dependent Fluorescence and Molecular Dynamics Simulation

The steady-state fluorescence spectra and molecular dynamics simulations were explored to investigate the temperature dependent organization in some imidazolium ionic liquids:1-butyl-3-methylimidazolium hexafluo-rophosphate([bmim][PF6]),1-ethyl-3-methylimidazolium ethylsulfate([emim][EtSO4]) and 1-butyl-3-methylimida-zolium tetrafluoroborate([bmim][BF4]).The pure room temperature ionic liquids(ILs) exhibit a large red shift at more than an excitation wavelength of around 340 nm,which demonstrates the hetero...     

Effect of water and organic solvents on the ionic dissociation of ionic liquids

The effect of water and several organic solvents on the density, viscosity, and conductivity of ionic liquids (ILs) 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-n-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), and 1-n-butyl-3-methylimidazolium trifluoroacetate ([bmim][CF3CO2]) was studied at 298.15 K in wide composition ranges. The density, viscosity, and conductivity of the three neat ILs were also determined at various temperatures. Upon the basis of the molar conductivity of the mixtures and that of the neat ILs of the same viscosity, the degree of dissociation of ILs in the solutions was investigated. It can be deduced that the organic solvents enhance the ionic association of the ILs, the effect depending on the solvent dielectric constant, while water promotes dissociation significantly due to its high dielectric constant and its ability to form strong hydrogen bonds with the anions of the ILs.     

Effect of imidazolium-based ionic liquids on the aggregation behavior of twin-tailed cationic gemini surfactant in aqueous solution

Micellization behavior of the twin-tailed surfactants can be modulated by the addition of various modifiers. Ionic liquids (ILs) are one of them and are documented here. The beauty of these environmentally benign neoteric molecules lies in their structural versatility. Here, we have investigated the effect of three ILs: 1-butyl-3-methylimidazolium bromide ([C₄mim][Br]), 1-hexyl-3-methylimidazolium bromide ([C₆mim][Br]), and 1-octyl-3-methylimidazolium bromide ([C₈mim][Br]) on the aggregation and surface adsorption behavior of cationic gemini surfactant, bis(hexadecyldimethyl ammonium)propane dibromide (16-3-16) through experimentally measured electrical conductivities, surface tensions, and by spectral methods (UV-vis absorbance and fluorescence measurements). The main focus of the study is to observe the effect of added ILs on the critical micelle concentration (cmc), various surface parameters, aggregation number, and size of the aggregates of gemini surfactant. The results show that the more hydrophobic ILs, that is, [C₆mim][Br] and [C₈mim][Br] behave as electrolyte at lower concentration and cosurfactant at higher concentration, whereas moderately hydrophobic IL [C₄mim][Br] acts as an electrolyte at all concentration ranges studied. The modulating effects of ILs were also compared with conventional electrolyte (NaBr) at similar conditions.     

Do anions influence the polarity of protic ionic liquids?

Polarity studies in two classes of imidazolium-based protic ionic liquids (PILs) possessing [HSO(4)](-), [HCOO](-), [CH(3)COO](-) and [CH(3)CH(2)COO](-) anions were carried out using a solvatochromic method from 298.15 to 353.15 K. For 1-methylimidazolium class of PILs, E(T)(30) was found to be independent over the entire range of temperature, while E(T)(30) was noted to decrease with a rise in temperature in the case of 1-butylimidazolium class of PILs containing [CH(3)COO](-) and [CH(3)CH(2)COO](-) anions. The E(T)(30) value decreases in both the classes upon varying the anions ([HSO(4)](-), [HCOO](-), [CH(3)COO](-) and [CH(3)CH(2)COO](-)). The E(T)(30) value is controlled by hydrogen bond acceptor basicity, β, and dipolarity/polarizability, π*. The E(T)(30) value for PILs varies inversely to the strength of the coulombic interaction between ions in PILs. Strong interactions between ions lead to lower E(T)(30) values. Unlike the poor thermal effect on E(T)(30), the Kamlet-Taft parameters i.e. α, β and π* have pronounced thermal effect in the imidazolium-based PILs. Variation in the Kamlet-Taft parameters is controlled by the stabilization of ions and the degree of proton transfer from Br?nsted acid to Br?nsted base.     

Studies of the reaction of dimethyltin dichloride with mercaptoacetic acid in the presence of amines and crystal structure of [(n-Pr)3NH][Me2Sn(μ-SCH2COO)Cl]

A series of new five-coordinated ionic organotin(IV) complexes with general formula [Q][Me₂Sn(μ²-SCH₂COO)Cl](Q = diethylammonium, triethylammonium, di-i-propylammonium, tripropylammonium, tri-n-butylammonium, pyrimidium, 3-picolinium, methylphenylammonium, dimethylphenylammonium) were synthesized by the reaction of mercaptoacetic acid with dimethyltin dichloride in the presence of an organic base. These complexes have been characterized by elemental analyses, IR and ¹H NMR spectroscopies. The crystal structure of [(n-Pr)₃NH][Me₂Sn(μ²-SCH₂COO)Cl] was determined by X-ray crystallography. The structure consists of an anion part, and a tri-n-propylammonium cation part as a counterion. The tin atom has a distorted cis-tbp geometry with two carbon and one sulfur atoms occupying the equatorial positions and the O atom and Cl atom occupying the axial positions. The organotin anion and its counterion are connected through a hydrogen bond between the N atom in the ammonium and the O atom of the carbonyl group with a N-O length of 2.766 Å.     

离子液体的组成及溶剂性质与木瓜蛋白酶催化特性的关系

离子液体的组成及溶剂性质对木瓜蛋白酶催化D,L-对羟基苯甘氨酸甲酯不对称水解反应有重要的影响. 木瓜蛋白酶在含CnMIm·BF4(n=2~6)介质中表现出较高的活性、对映体选择性及稳定性, 而在含有C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3, C4MIm·CH3COO的介质中表现较低的对应值. 在含有CnMIm·BF4(n=2~6)的介质中, 酶活性随离子液体的极性增大而提高, 但在含有C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3, C4MIm·CH3COO的介质中随离子液体的极性增大反而降低. 木瓜蛋白酶的对映体选择性和稳定性均随着离子液体的疏水性增大而提高. 荧光分析结果表明, 离子液体对酶分子构象具有显著的影响. 在CnMIm·BF4(n=2~6)的介质中, 木瓜蛋白酶的最大荧光发射波长(λmax)均蓝移, 而在含有C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3或C4MIm·CH3COO的介质中, λmax均红移. 与CnMIm·BF4(n=2~6)相比, 在C4MIm·HSO4, C4MIm·Cl, C4MIm·NO3或C4MIm·CH3COO中, 酶分子构象的变化较大, 暴露的疏水区域较多.     

Effect of anionic structure on the phase formation and hydrophobicity of amino acid ionic liquids aqueous two-phase systems

Compared with the conventional ionic liquids, amino acid ionic liquids are more biodegradable and biocompatible, and can enhance stability of biomaterials. In this work, amino acid ionic liquids 1-butyl-3-methylimidazolium L-serine ([C(4)mim][Ser]), 1-butyl-3-methylimidazolium glycine ([C(4)mim][Gly]), 1-butyl-3-methylimidazolium L-alanine ([C(4)mim][Ala]) and 1-butyl-3-methylimidazolium L-leucine ([C(4)mim][Leu]) have been synthesized. These ionic liquids are found to form aqueous two-phase systems (ATPSs) by the salted-out of K(3)PO(4) in aqueous solutions. Phase diagram of the ATPSs and the Gibbs energies of transfer of methylene group from the bottom salt-rich phase to the top ionic liquid-rich phase have been determined at 298.15K and pH 14, and the effect of anionic structure of the ionic liquids on phase formation of the ATPSs and the relative hydrophobicity between the top and the bottom phases are then examined. In order to understand the effect of relative hydrophobicity of the phases in equilibrium in the ATPSs on the extraction/separation capability of biomolecules, the partition coefficients of cytochrome-c (as a model biomolecule) in the ATPSs are measured by spectrophotometry. It is suggested that hydrophobic interactions are mainly responsible for the higher partition coefficients of cytochrome-c in aqueous two-phase systems at pH 14, and the extraction and separation capacity of biomolecules can be improved by the modulation of the relative hydrophobicity of the phases and/or the pH of the system.     

Protein structure and dynamics in ionic liquids. Insights from molecular dynamics simulation studies

We present in this work the first molecular simulation study of an enzyme, the serine protease cutinase from Fusarium solani pisi, in two ionic liquids (ILs): 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) and 1-butyl-3-methylimidazolium nitrate ([BMIM][NO(3)]). We tested different water contents in these ILs at room temperature (298 K) and high temperature (343 K), and we observe that the enzyme structure is highly dependent on the amount of water present in the IL media. We show that the enzyme is preferentially stabilized in [BMIM][PF6] at 5-10% (w/w) (weight of water over protein) water content at room temperature. [BMIM][PF6] renders a more nativelike enzyme structure at the same water content of 5-10% (w/w) as previously found for hexane, and the system displays a similar bell-shape-like dependence with the water content in the IL media. [BMIM][PF6] is shown to increase significantly the protein thermostability at high temperatures, especially at low hydration. Our analysis indicates that the enzyme is less stabilized in [BMIM][NO(3)] relative to [BMIM][PF6] at both temperatures, most likely due to the strong affinity of the [NO(3)]- anion toward the protein main chain. These findings are in accordance with the experimental knowledge for these two ionic liquids. We also show that these ILs "strip off" most of the water from the enzyme surface in a degree similar to that found for polar organic solvents such as acetonitrile, and that the remaining waters at the enzyme surface are organized in many small clusters.     

Isobaric vapor–liquid equilibria for ethanol–water system containing different ionic liquids at atmospheric pressure

Isobaric vapor–liquid equilibrium (VLE) data for ethanol–water systems containing ionic liquids (ILs) 1-methyl-3-methylimidazolium dimethylphosphate ([MMIM][DMP]), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]), 1-butyl-3-methylimidazolium bromide ([BMIM][Br]), 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]) at atmospheric pressure (101.32 kPa) were measured with a circulation still. The results showed that the VLE of ethanol–water systems in the presence of different ILs was obviously different from that of the IL-free system. All ILs studied showed a salting-out effect, which gave rise to a change of the relative volatility of ethanol, and even to an elimination of the azeotropic point. It was found that the salting-out effect followed the order of [BMIM][Cl] > [BMIM][Br] > [BMIM][PF₆] and [MMIM][DMP] > [EMIM][DEP], which was ascribed to the preferential solvation ability of the ions resulting from the dissociation of the IL.     

Activity and stability of α-chymotrypsin in biocompatible ionic liquids: enzyme refolding by triethyl ammonium acetate

In view the of wide scope of structural information of biomolecules in biocompatible ionic liquids (ILs) in various applications including chemical and biochemical, it is essential to study the productive preferential interactions between biological macromolecules and biocompatible ILs. We have therefore explored the stability and activity of α-chymotrypsin (CT) in the presence of five ILs from different families, such as triethyl ammonium acetate (TEAA), triethyl ammonium phosphate (TEAP) from ammonium salts, 1-benzyl-3-methylimidazolium chloride ([Bzmim][Cl]), 1-benzyl-3-methylimidazolium tetrafluoroborate ([Bzmim][BF(4)]) from imidazolium salts and tetra-butyl phosphonium bromide (TBPBr) from phosphonium families. Circular dichroism (CD) and UV-vis spectrophotometer experiments were used to study CT stabilization by ILs, related to the associated structural changes and enzyme activity studies, respectively. We observed that all ILs have a dominant contribution to the stabilization of CT. The stability and activity of CT depends on the structural arrangement of the ions of ILs. Our experimental results explicitly elucidate that more hydrophobic imidazolium and phosphonium cations carrying longer alkyl chains of ILs ([Bzmim][Cl], [Bzmim][BF(4)] and TBPBr) were weak stabilizers for CT, while small alkyl chain molecules of triethyl ammonium salts (TEAA and TEAP) are strong stabilizers and therefore more biocompatible for CT stability. Our CD and NMR measurements reveal that TEAA is a refolding additive for CT from a quenched thermal unfolded enzyme structure.     

Hydro-ionothermal syntheses, crystal structures, and properties of five new divalent metal iminophosphonates

The use of a moderately hydrophobic ionic liquid, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BdMIM][BF(4)]), as a cosolvent with water, has been investigated in the synthesis of metal phosphonates. This hydro-ionothermal synthesis has been carried out through a systematic combinatorial investigation of several divalent metal chlorides and two related ligands, iminobis(methylphosphonic acid) and N-methyliminiobis(methylphosphonic acid). These reactions resulted in five new divalent metal phosphonates. We present here the synthetic techniques utilized as well as the X-ray structures and characteristic properties of each of these compounds. Co(HO(3)PCH(2)NH(2)CH(2)PO(3)H)(2), (1), consists of sheets that are hydrogen bonded together by pairs of P-O···H groups. Co(H(2)O)(2)(HO(3)PCH(2)NH(2)CH(2)PO(3)H)(2), (2), consists of chains that are connected through an extensive network of hydrogen bonds. Co(HO(3)PCH(2)NH(CH(3))CH(2)PO(3)H)(2), (3), is made up of sheets that are hydrogen bonded together by pairing P-O···H interactions. Zn(3)(O(3)PCH(2)NH(2)CH(2)PO(3))(2), (4), is isostructural to a previously reported cobalt compound which is a non-porous 3-dimensional network. CuClPO(3)CH(2)NH(2)CH(3), (5), formed as a result of an in situ N-C bond cleavage. Ladders built of Cu-O-P-O 8-membered rings are crosslinked by bridging chloride atoms to form sheets. 1, 3, 4 and 5 have been synthesized using the hydrophobic ionic liquid 1-butyl-2,3-dimethylimidazolium tetrafluoroborate ([BdMIM][BF(4)]) with water as a cosolvent, while 2 has been synthesized from identical conditions in the absence of the [BdMIM][BF(4)]. We also report the microwave assisted hydro-ionothermal synthesis of the known polymorph of 2, Co(H(2)O)(2)(HO(3)PCH(2)NH(2)CH(2)PO(3)H)(2), (6), synthesized in two hours providing high quality crystals in good yield. The compounds have been characterized by thermogravimetric analysis and IR spectroscopy, and their magnetic properties have been investigated.     

Estimation of physicochemical properties of ionic liquids 1-alkyl-3-methylimidazolium chloroaluminate

The density and surface tension of ionic liquids [C(2)mim][AlCl(4)] (1-ethlyl-3-methyl imidazolium chloroaluminate) and [C(6)mim][AlCl(4)] (1-hexyl-3-methylimidazolium chloroaluminate) were measured in the temperature range from 283.15 to 338.15 +/- 0.05 K. In terms of these experimental results, the estimation of physicochemical properties of 1-alkyl-3-methylimidazolium chloroaluminate ([C(n)mim][AlCl(4)], n = 1-6) was carried out. With the use of the parachor, the values of surface tension of the ILs were predicted. In terms of Glasser's theory, the standard molar entropy, lattice energy, and surface properties of the ILs were estimated. With the use of Kabo's method and Rebelo's method, the molar enthalpy of vaporization of the ILs, Delta(l)(g)H(m)(0), was predicted. According to the interstice model, the values of the thermal expansion coefficient of the ILs were also estimated. Since the magnitude order of the thermal expansion coefficient estimated by the model is in good agreement with that measured experimentally, this result means that the interstice model is reasonable.     

Electrophilic nitration of aromatics in ionic liquid solvents.

Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Hünig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid.