The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Robert W Carper - One of the best experts on this subject based on the ideXlab platform.
-
vibrational spectra of imidazolium Tetrafluoroborate ionic liquids
Journal of Molecular Liquids, 2006Co-Authors: Norman E Heimer, Rico E Del Sesto, Zhizhong Meng, John S Wilkes, Robert W CarperAbstract:Abstract The Raman and infrared spectra of a series of 1-alkyl-3-methylimidazolium Tetrafluoroborate ionic liquids ([C2-4MIM][BF4]) are reported and analyzed using Density Functional Theory (DFT) and RHF methods at the 6-311+G(2d,p) computational level. The B3LYP (DFT) and RHF calculations reproduce the vibrational spectra of 1-ethyl-3-methyl imidazolium Tetrafluoroborate [EMIM][BF4], 1-propyl-3-methyl imidazolium Tetrafluoroborate [PMIM][BF4] and 1-butyl-3-methyl imidazolium Tetrafluoroborate [BMIM][BF4] using correction factors of 0.963–0.967 (DFT) and 0.913–0.916 (RHF) with correlation coefficients R2 of 0.999 using the fully optimized structures. Theoretical (DFT) alkyl side chain conformational changes in the 1-alkyl-3-methyl Tetrafluoroborate ionic liquids have only a limited effect on the theoretical gas phase vibrations. The gas phase molecular structures of the [C2–4MIM][BF4] ion pairs suggest hydrogen bonding interactions between the fluorine atoms of the BF4− anion and the C2 hydrogen on the imidazolium ring. Additional interactions are observed between [BF4] and H atoms on the adjacent alkyl side chains in all polymorphic structures.
Chiaki Yokoyama - One of the best experts on this subject based on the ideXlab platform.
-
Densities and thermal conductivities of N -alkylpyridinium Tetrafluoroborates at high pressure
Fluid Phase Equilibria, 2013Co-Authors: Daisuke Tomida, Satoshi Kenmochi, Takao Tsukada, Kun Qiao, Chiaki YokoyamaAbstract:Abstract Densities and thermal conductivities are reported for a series of N-alkylpyridinium Tetrafluoroborate compounds with butyl (N-butylpyridinium Tetrafluoroborate), hexyl (N-hexylpyridinium Tetrafluoroborate) and octyl (N-octylpyridinium Tetrafluoroborate) groups. The densities were measured with a vibrating tube densimeter over the temperature range 293–353 K at pressures ≤20.0 MPa. The transient short hot wire method was used to measure thermal conductivity over the temperature range 294–335 K at pressures ≤20 MPa. It was found that the effect of alkyl chain length on thermal conductivities in N-alkylpyridinium Tetrafluoroborates is the same degree as 1-alkyl-3-methylimidazolium Tetrafluoroborates. The experimental values at 293 K and 0.1 MPa were consistent with the predicted values proposed by Froba et al.
-
Viscosity and Thermal Conductivity of 1-Hexyl-3-methylimidazolium Tetrafluoroborate and 1-Octyl-3-methylimidazolium Tetrafluoroborate at Pressures up to 20 MPa
International Journal of Thermophysics, 2012Co-Authors: Daisuke Tomida, Satoshi Kenmochi, Takao Tsukada, Kun Qiao, Quanxi Bao, Chiaki YokoyamaAbstract:Viscosity and thermal conductivity values are reported for a series of 1-alkyl-3-methylimidazolium Tetrafluoroborate compounds with hexyl (1-hexyl-3-methylimidazolium Tetrafluoroborate) and octyl (1-octyl-3-methylimidazolium Tetrafluoroborate) groups. The viscosity was measured with a rolling-ball viscometer at 293.15 K to 353.15 K and pressures up to 20.0 MPa. The experimental values were correlated with a hybrid VFT–Tait equation. The thermal conductivity was measured using the transient short hot-wire method at 294 K to 335 K and pressures up to 20.0 MPa. The experimental values at 293.15 K and 0.1 MPa agreed with the predicted values proposed by Froba et al.
-
Viscosity and Thermal Conductivity of 1-Hexyl-3-methylimidazolium Tetrafluoroborate and 1-Octyl-3-methylimidazolium Tetrafluoroborate at Pressures up to 20 MPa
International Journal of Thermophysics, 2012Co-Authors: Daisuke Tomida, Satoshi Kenmochi, Takao Tsukada, Kun Qiao, Quanxi Bao, Chiaki YokoyamaAbstract:Viscosity and thermal conductivity values are reported for a series of 1-alkyl-3-methylimidazolium Tetrafluoroborate compounds with hexyl (1-hexyl-3-methylimidazolium Tetrafluoroborate) and octyl (1-octyl-3-methylimidazolium Tetrafluoroborate) groups. The viscosity was measured with a rolling-ball viscometer at 293.15 K to 353.15 K and pressures up to 20.0 MPa. The experimental values were correlated with a hybrid VFT–Tait equation. The thermal conductivity was measured using the transient short hot-wire method at 294 K to 335 K and pressures up to 20.0 MPa. The experimental values at 293.15 K and 0.1 MPa agreed with the predicted values proposed by Fröba et al.
Vladimír Macháček - One of the best experts on this subject based on the ideXlab platform.
-
diazonium exchange and migration of pivaloyl group upon azo coupling of β enaminones
European Journal of Organic Chemistry, 2013Co-Authors: Petr Simůnek, Valerio Bertolasi, Vladimír MacháčekAbstract:4,4-Dimethyl-1-methylamino-1-phenyl-2-(substituted phenyldiazenyl)pent-1-en-3-ones (prepared upon azo coupling of 4,4-dimethyl-1-methylamino-1-phenylpent-1-en-3-one 6a with the corresponding benzenediazonium Tetrafluoroborates) react with another molecule of substituted benzenediazonium Tetrafluoroborate (in dichloromethane in the presence of anhydrous sodium acetate) to form substituted 4,4-bis(substituted phenyldiazenyl) derivatives 8. The second azo coupling is reversible. Derivatives 8 undergo either reverse cleavage of a diazonium ion or [1,3] sigmatropic rearrangement forming substituted formazane 9. In the case of the sequential use of two different diazonium Tetrafluoroborates, the less electrophilic group splits off more easily. The structures of the products 9 were studied by means of X-ray, 1H, 13C, 19F and 15N NMR and MALDI HRMS analyses. The formazans 9 exhibit a reduced mobility of the phenyl group adjacent to the pivaloyl group, giving rise to anisochronism of proton and carbon atoms, to eventually form conformers. The reduced mobility was observed by means of NMR spectroscopy. A temperature dependence of the spectral behaviour was also studied.
-
Synthesis of some phenylazonaphthols in an ionic liquid
Dyes and Pigments, 2007Co-Authors: Antonín Lyčka, A. Koloničný, Petr Šimůnek, Vladimír MacháčekAbstract:Abstract Several phenylazonaphthols were prepared in 1-butyl-3-methylimidazolium Tetrafluoroborate (an ionic liquid) using a coupling reaction of (4-X-benzene)diazonium Tetrafluoroborates (X = H and NO 2 ) with 1- and 2-naphthols and their sodium salts. 1 H NMR spectra of the reaction products were measured and results compared with previously published data. The reaction of benzenediazonium Tetrafluoroborates with sodium salts of 1- and 2-naphthols in 1-butyl-3-methyl-imidazolium Tetrafluoroborate was faster compared with that when 1- and 2-naphthols were used. 4-Nitrobenzenediazonium Tetrafluoroborate was much more reactive than benzenediazonium Tetrafluoroborate.
Shengyin Zhao - One of the best experts on this subject based on the ideXlab platform.
-
selective and tunable synthesis of 3 arylsuccinimides and 3 arylmaleimides from arenediazonium Tetrafluoroborates and maleimides
RSC Advances, 2016Co-Authors: Zhenhua Yang, Zhonghui Chen, Shengyin ZhaoAbstract:A highly efficient synthetic strategy for synthesizing 3-arylsuccinimides has been developed from arenediazonium Tetrafluoroborates and maleimides in the presence of TiCl3. The reactions generated 3-arylsuccinimides in satisfactory yields under mild reaction conditions. In addition, 3-arylmaleimides were obtained by the coupling of arenediazonium Tetrafluoroborate and maleimides catalyzed by CuCl. This methodology provided the selective and tunable synthesis of two classes of products by simply switching different metal reagents. The methods are simple, efficient and practical.
Daisuke Tomida - One of the best experts on this subject based on the ideXlab platform.
-
Densities and thermal conductivities of N -alkylpyridinium Tetrafluoroborates at high pressure
Fluid Phase Equilibria, 2013Co-Authors: Daisuke Tomida, Satoshi Kenmochi, Takao Tsukada, Kun Qiao, Chiaki YokoyamaAbstract:Abstract Densities and thermal conductivities are reported for a series of N-alkylpyridinium Tetrafluoroborate compounds with butyl (N-butylpyridinium Tetrafluoroborate), hexyl (N-hexylpyridinium Tetrafluoroborate) and octyl (N-octylpyridinium Tetrafluoroborate) groups. The densities were measured with a vibrating tube densimeter over the temperature range 293–353 K at pressures ≤20.0 MPa. The transient short hot wire method was used to measure thermal conductivity over the temperature range 294–335 K at pressures ≤20 MPa. It was found that the effect of alkyl chain length on thermal conductivities in N-alkylpyridinium Tetrafluoroborates is the same degree as 1-alkyl-3-methylimidazolium Tetrafluoroborates. The experimental values at 293 K and 0.1 MPa were consistent with the predicted values proposed by Froba et al.
-
Viscosity and Thermal Conductivity of 1-Hexyl-3-methylimidazolium Tetrafluoroborate and 1-Octyl-3-methylimidazolium Tetrafluoroborate at Pressures up to 20 MPa
International Journal of Thermophysics, 2012Co-Authors: Daisuke Tomida, Satoshi Kenmochi, Takao Tsukada, Kun Qiao, Quanxi Bao, Chiaki YokoyamaAbstract:Viscosity and thermal conductivity values are reported for a series of 1-alkyl-3-methylimidazolium Tetrafluoroborate compounds with hexyl (1-hexyl-3-methylimidazolium Tetrafluoroborate) and octyl (1-octyl-3-methylimidazolium Tetrafluoroborate) groups. The viscosity was measured with a rolling-ball viscometer at 293.15 K to 353.15 K and pressures up to 20.0 MPa. The experimental values were correlated with a hybrid VFT–Tait equation. The thermal conductivity was measured using the transient short hot-wire method at 294 K to 335 K and pressures up to 20.0 MPa. The experimental values at 293.15 K and 0.1 MPa agreed with the predicted values proposed by Froba et al.
-
Viscosity and Thermal Conductivity of 1-Hexyl-3-methylimidazolium Tetrafluoroborate and 1-Octyl-3-methylimidazolium Tetrafluoroborate at Pressures up to 20 MPa
International Journal of Thermophysics, 2012Co-Authors: Daisuke Tomida, Satoshi Kenmochi, Takao Tsukada, Kun Qiao, Quanxi Bao, Chiaki YokoyamaAbstract:Viscosity and thermal conductivity values are reported for a series of 1-alkyl-3-methylimidazolium Tetrafluoroborate compounds with hexyl (1-hexyl-3-methylimidazolium Tetrafluoroborate) and octyl (1-octyl-3-methylimidazolium Tetrafluoroborate) groups. The viscosity was measured with a rolling-ball viscometer at 293.15 K to 353.15 K and pressures up to 20.0 MPa. The experimental values were correlated with a hybrid VFT–Tait equation. The thermal conductivity was measured using the transient short hot-wire method at 294 K to 335 K and pressures up to 20.0 MPa. The experimental values at 293.15 K and 0.1 MPa agreed with the predicted values proposed by Fröba et al.
