20726-63-0Relevant articles and documents
Protic ionic liquids as catalysts for a three-component coupling/hydroarylation/dehydrogenation tandem reaction
Muntzeck, Maren,Wilhelm, René
, p. 515 - 519 (2018)
Protic ionic liquids with nitrate anions were used as solvents and catalysts for a three-component oxidative dehydrogenation tandem reaction via the coupling and hydroarylation of benzaldehyde, aniline, and phenylacetylene to a quinoline derivative. The reaction was supported by air and microwave irradiation. The presence of nitrate as counter anion in the protic ionic liquids was essential for the reaction.
Measurements and molecular interactions for N, N-dimethylformamide with ionic liquid mixed solvents
Attri, Pankaj,Reddy, P. Madhusudan,Venkatesu,Kumar, Anil,Hofman
, p. 6126 - 6133 (2010)
To understand the molecular interactions between N,N-dimethylformamide (DMF) with two families of ionic liquids (ILs), we have measured thermophysical properties such as densities and ultrasonic sound velocities (u) over the whole composition range at 25 ?°C under atmospheric pressure. The excess molar volume (VE) and the deviation in isentropic compressibilities (??Ks) were predicted using these properties as a function of the concentration of IL. These results are fitted to the Redlich-Kister polynomials. The materials investigated in the present study included two families of ILs such as ammonium salts and imidazolium salts. Diethylammonium acetate ([Et2NH][CH3COO], DEAA), triethylammonium actetate ([Et3NH][CH3COO], TEAA), triethylammonium dihydogen phosphate ([Et3NH][H2PO4], TEAP), and triethylammonium sulfate ([Et3NH][HSO4], TEAS) are ammonium salts and 1-benzyl-3-methylimidazolium chloride ([Bmim][Cl]) belongs to the imidazolium family. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. ? 2010 American Chemical Society.
The local composition behavior in binary solutions of diethylamine acetate ionic liquid
Zhu, Xiao,Zhang, Huan,Xu, Yingjie
, p. 139 - 144 (2016)
In order to uncover the micro-structural heterogeneities in the solutions of ammonium-based ionic liquids, diethylamine acetate (DEAA) has been synthesized and concentration-dependent 1H NMR spectra of three binary solutions, namely DEAA/water,
Temperature effect on the molecular interactions between two ammonium ionic liquids and dimethylsulfoxide
Govinda, Varadhi,Attri, Pankaj,Venkatesu,Venkateswarlu
, p. 218 - 225 (2011)
To understand the molecular interactions between newly synthesized ammonium ionic liquids (ILs) and highly polar solvent dimethylsulfoxide (DMSO), precise measurements such as densities (ρ), ultrasonic sound velocities (u) and viscosities (η) have been performed over the whole composition range at temperature ranging from 298.15 to 308.15 K and at atmospheric pressure. The ILs investigated in the present study included diethyl ammonium acetate ([Et 2NH][CH3COO], DEAA) and triethyl ammonium acetate ([Et3NH][CH3COO], TEAA). Further, to gain some insight into the nature of molecular interactions in these mixed solvents, we predicted the excess molar volume (VE), the deviation in isentropic compressibilities (ΔKs) and deviation in viscosity (Δη) as a function of the concentration of IL using the measured properties of ρ, u and η, respectively. Redlich-Kister polynomial was used to correlate the results. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMSO molecules and their structural factors.
Understanding the Role of Protic Ionic Liquids (PILs) in Reactive Systems: Rational Selection of PILs for the Design of Green Synthesis Strategies for Allylic Amines and β-Amino Esters
Bravo, María V.,Fernández, José L.,Adam, Claudia G.,Della Rosa, Claudia D.
, p. 919 - 926 (2019)
The reactive behaviour of protic ionic liquids (PILs) has been shown to be governed not only by their chemical structures but also by their global compositions, which include the presence of free acids and bases at equilibrium with ionic pairs. Six PILs composed of primary, secondary, or tertiary alkyl ammonium cations with two couterions, nitrate or acetate, were tested in model reactions with unsaturated substrates. The free species that were naturally present in these liquids were identified by cyclic voltammetry. Only tributylammonium nitrate was found to be mostly composed just of the ionic pair; the other five PILs also contain variable amounts of free acid and amine. In reactive systems, these free species determine the products of the reaction. In particular, allylic amines and β-amino esters were obtained in good yields (91 and 75 %, respectively) by reaction of conjugated dienes and acrylates in the presence of PILs. By taking into account the actual composition of each PIL, it was possible to direct the reaction path towards a specific product with good yields, to ensure acid catalysis, to avoid polymerization of the substrate, and to promote phase transfer of products. These results establish some useful guidelines for the rational design of new PIL-based one-step synthetic strategies.
Theoretical and experimental studies on proton transfer in acetate-based protic ionic liquids
Sun, Xuejun,Cao, Bobo,Zhou, Xinming,Liu, Shuangyue,Zhu, Xiao,Fu, Hu
, p. 254 - 261 (2016/07/06)
In this study, the proton transfer of three protic ionic liquids (PILs) pyrrolidinium acetate ([Pyrrol]OAc), diethylammonium acetate ([DEA]OAc) and bis-(2-methoxyethyl)-ammonium acetate ([BMOEA]OAc) were investigated. At first, the structures of the ion-pairs and molecular pairs of these PILs were optimized at B3LYP/6-311 ++G(d,p) level. The interaction energy between anions and cations was also obtained. The proton transfer processes were verified by intrinsic reaction coordinate (IRC) pathways tracing to the energy profiles connecting the transition state (TS) to the two desired minima, i.e. ion pair and molecular pair. The experimental attenuated total reflection (ATR) FTIR spectra of these PILs at room temperature were determined and compared with the results calculated at B3LYP/6-311 ++G(d,p) level. Vibrational mode analyses (VMA) for [Pyrrol]OAc found that δ(NH) has an imaginary frequency (- 147.3 cm- 1), which is accounted for proton transfer from [NH2]+ to OAc-. Natural bond orbital (NBO) analyses pointed out that second order perturbation stabilization energy of (E(2)) of LP(N1) → σ?(O2-H5) was much larger than that of other orbitals, and should be the symmetrical matching with the maximum overlap and the minimum gap (0.73 au). The hybridized index of N atom is varied from sp3.65 in ionic pair to sp4.49 in TS. The constituent of s orbital decreases 3.3% and the length of N1-H5 increases from 1.02 ? in ionic pair to 1.65 ? in TS, and the symmetric stretching vibration takes place the red shift. It could be explained that the N1-O2-H5 played an important role in the stabilization of molecular pair. The electron density ρ(r) and the Laplacian of the electron density ?2ρ(r) derived from atoms in molecules (AIM) analyses were used to describe the intensity and characteristic of a bond. The results indicate that a very strong interaction of the hydrogen bonds exists in the ion-pair geometries and the bonds are the covalent bond.
