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1.
《Fluid Phase Equilibria》1998,152(2):283-298
The results of excess molar volumes for ternary mixture N,N-dimethylformamide (DMF)+1-propanol+water and for binary constituents, DMF+water, DMF+1-propanol and 1-propanol+water at 298.15 K are reported. Several empirical expressions were used to predict and correlate the ternary excess molar volumes from experimental results on the constituent binaries. A pseudo-binary mixture approach (PBMA) was used to analyze the system studied. The partial molar volumes of 1-propanol at infinite dilution in [fmDMF+(1−fm)water] mixed solvents at their several fixed composition fm were evaluated and correlated with the composition fm. 相似文献
2.
《Physics and Chemistry of Liquids》2012,50(4):453-464
Abstract Densities of the systems, 1-Propanol(P)+aniline(A), 1-Propanol(P)+N-Methylaniline (NMA) and 1-Propanol(P)+N,N-Dimethylaniline(DMA) have been measured from 21°C to 50°C at an interval of 5°C. The excess molar volumes, V E, of the systems, P+A and P +NMA have been found to be negative for the whole range of composition. VE of the system P+DMA has also been found to be negative, except in DMA-rich region where small positive excess volume is observed. The negative excess volume has been explained primarily in terms of strong specific interaction and size difference of unlike molecules. The magnitude of the negative excess volumes of these systems is of the order, P+A > P + NMA > P + DMA, which has been strongly influenced by steric effect due to CH3 group attached to N-atom of NMA and DMA. In the highly rich region of DMA in P+DMA system the small positive excess volume is accounted for by the steric effect and breaking up of H-bond of 1-Propanol. 相似文献
3.
Summary: Superporous N-isopropylacrylamide (NIPAAm) and N,N-diethylacrylamide (DEAAm) copolymers with N,N'-methylenebisacrylamide (MBAAm) were prepared by radical polymerization with the aim to determine their temperature-dependent changes in polarity by liquid chromatography. Superpores were formed by the salt-leaching technique using NaCl as a porogen. Porosities of the hydrogels characterized by water regain and mercury porosimetry, ranging from 81 to 91%, were proportional to the volume of NaCl porogen in the feed. The retention volumes of several phenols decreased with increasing temperature as polarity of the hydrogels decreased. A jump change in solute retention volume was observed at ca. 32 °C in PNIPAAm and at ca. 35 °C in PDEAAm indicating a change in the mechanism of interaction. The Gibbs energy changes ΔGCH2 were rather low, increasing in the order phenol < benzyl alcohol < ethanol < butan-1-ol. In contrast to the solutes, retention volumes of bovine serum albumin and dextrans were higher at higher temperature confirming thus hydrophobic interactions of the compounds with the studied hydrogels. 相似文献
4.
Elizabeth P. Juárez-Camacho María E. Manríquez-Ramírez Carmen M. Reza-San?Germán Abel Zú?iga-Moreno 《Journal of solution chemistry》2012,41(9):1575-1586
Volumetric properties for the trihexyltetradecylphosphonium bromide (CYPHOS IL 102) + N,N-dimethylformamide (DMF) binary system were determined at temperatures from T=293.15 to 313.15?K and ambient pressure (p=0.7 atm). Densities were measured by means of a vibrating tube densimeter (VTD). These measurements covered the full range of compositions along with the pure compounds; expansion coefficients, excess molar volumes, and partial molar volumes were calculated from the experimental densities. Excess molar volumes were fitted to a Redlich?CKister type equation. The excess molar volumes exhibit negative deviations from ideal behavior. 相似文献
5.
Vasiliy G. Shtamburg Alexander V. Tsygankov Oleg V. Shishkin Roman I. Zubatyuk Victor V. Shtamburg Mikhail V. Gerasimenko Alexander V. Mazepa Remir G. Kostyanovsky 《Mendeleev Communications》2012,22(2):92-94
N-Alkoxy-N-(4-dimethylaminopyridin-1-ium-1-yl)-substituted ureas, benzamides and N-tert-alkylamines were prepared by the reac tion of the corresponding (N-chloro-N-alkoxy)amino compounds with 4-dimethylaminopyridine. The XRD study of N-alkoxy-N-(4-dimethylaminopyridin-1-ium-1-yl)ureas has revealed the high pyramidality of the central nitrogen atom in O–N–N+ geminal system. 相似文献
6.
In the search for an approach to N-vinyltriflamides with a free NH group TfNHCH=CHR (Tf = CF3SO2) N-(benzyl)-N-(2-bromo-2-phenylethenyl)triflamide TfN(Bn)CH=CHPh was synthesized through bromination-dehydrobromination of N-(benzyl)-N-(2-phenylethyl)triflamide. At removing the benzyl protecttion by the action of trifluoromethanesulfonic acid benzyl alcohol separated; however instead of the target N-styryltriflamide unexpectedly the product of its hydrogenation was obtained, N-(2-phenylethyl)triflamide. Obviously, the benzyl alcohol was the hydrogen donor, and the easy hydrogenation was facilitated by the high electrophilicity of the double bond in N-styryltriflamide because of strong electron-acceptor effect of the triflyl group. 相似文献
7.
《Fluid Phase Equilibria》1996,126(2):241-255
The densities, heat capacities and enthalpies of dilution at 298 K and the osmotic coefficients at 310 K were measured for N,N,N-octyloctyldimethylammonium chloride (OOAC) in aqueous urea solution as a function of urea (mu) and surfactant (ms) concentrations in order to determine, in comparison with the lower homologue N,N,N-pentyloctyldimethylammonium chloride, OPAC, the influence of the hydrophobic tail on the properties of a double-chain surfactant in the presence of an additive like urea. From specific conductivity data, the critical micelle concentration (cmc) and the degree of the counterion dissociation (β) have been calculated.From the thermodynamic data, the molar apparent volumes, Vφ, heat capacities, Cφ, and apparent molar relative enthalpies, Lφ, were derived as a function of mu and ms at 298 K. 相似文献
8.
Lydia Suba Tann Schafer Peter G. Ruminski John J. D'amico 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2-4):219-226
Abstract The reactions of S,S' methyl cyanodithioimidocarbonate with potassium hydroxide in alkyl or benzyl alcohol furnished the O-alkyl and benzyl O-potassium cyanoimidocarbonates (1–5). The reaction of the potassium salts (1,3, or 4) with a 10% excess of alkyl, allyl or benzyl halides afforded the unknown titled carbamates (6–17). The reaction of 2 with 10% excess benzyl bromide or 5 with 10% excess methyl iodide gave the same product, N-benzyl-N-methyl cyanamide (18). The reactions of 2 with 10% and 55% excess allyl bromide afforded N-allyl-N-methyl cyanamide (19) and N,N-diallyl cyanamide (20), respectively. The reaction of 3 with 28% excess of allyl iodide furnished N-allyl-N-propyl cyanamide (21). Possible mechanisms and supporting NMR, IR and mass spectra data are discussed. 相似文献
9.
We present nonadiabatic quantum dynamical calculations on the two coupled potential en-ergy surfaces (12A′ and 22A′) [J. Theor. Comput. Chem. 8, 849 (2009)] for the reaction. Initial state-resolved reaction probabilities and cross sections for the N+ND→N2+D reaction and N′+ND→N′D+N reaction for collision energies of 5 meV to 1.0 eV are determined, re-spectively. It is found that the N+ND→N2+D reaction is dominated in the N+ND reaction.In addition, we obtained the rate constants for the N+ND→N2+D reaction which demand further experimental investigations. 相似文献
10.
Dharam V.S. Jain Vijay K. Singla Suraj B. Saini Rajwant S. Sidhu 《The Journal of chemical thermodynamics》1983,15(12):1105-1107
Excess molar volumes VmE as function of mole fraction x for methylcyclohexane + benzene, + methylbenzene, + 1,4-dioxane, and + tetrahydrofuran are reported at 303.15 K. The excess molar volumes are positive and indicate the presence of weak interactions. 相似文献
11.
《Tetrahedron: Asymmetry》1999,10(13):2627-2633
In our series of nucleophilic substitution reactions on N,N-disulfonylimides we hereby report the preparation and the nucleophilic substitution of the N,N-1,2-naphthalenedisulfonylimide derivative 1a of the chiral amine 1. The disulfonimide was prepared by using the disulfonyl chloride reagent. Nucleophilic substitution of 1a by KNO2 and azide afforded the corresponding alcohol 2 and the azide product 3 with, respectively, 63 and 70% inversion of configuration. The stereochemical results are compared with previously reported results for a series of N,N-disulfonylimides showing that the degree of inversion of 1a is lower than for the other N,N-disulfonylimides. 相似文献
12.
《Fluid Phase Equilibria》1999,166(1):53-65
This paper reports experimental densities and refractive indices of the binary systems tert-butyl alcohol (TBA)+toluene, +isooctane, and +methylcyclohexane, and toluene+methylcyclohexane, and the ternary system TBA+toluene+methylcyclohexane, over the entire range of composition at 298.15 K. Excess molar volumes and changes of refractive indices were evaluated from the experimental data obtained. These derived properties were fitted to variable-degree polynomials. The experimental values of physical properties were compared with the values estimated by different methods of prediction. 相似文献
13.
M. Zh. Ovakimyan S. K. Basergyan N. M. Kikoyan M. G. Indzhikyan 《Russian Journal of General Chemistry》2006,76(9):1393-1396
The reactions of N,N-dimethylhydrazine and N-aminopiperidine with potential triphenylvinyl-and-propenylphosphonium bromides were used to obtain adducts by the α,β-double bonds of the latter. The resulting [2-(N’,N’-dimethylhydrazino)ethyl]phosphonium salts just on moderate heating in alcohol undergo dehydration leading to the corresponding hydrazone or α,β-unsaturated hydrazine derivatives. Contrary to that, [2-(N’,N’dimethylhydrazino)-2-methylethyl]triphenylphosphonium bromide under the same conditions does not undergo dehydration. The reaction of (3-bromopropyl)-and (4-bromobutyl)triphenylphosphonium bromides with N,N-dimethylhydrazine gives phosphoniohydrazinium salts with a tri-or tetramethylene common radical. When treated with equimolar amount of ethanolic sodium ethylate, the latter products undergo alkaline reduction of one of the phenyl groups to give the corresponding diphenylphosphinoylalkylhydrazinium salts in high yields. 相似文献
14.
Lin Yan Jiarou Peng Xianyun Jiao Mengshen Cai 《Journal of mass spectrometry : JMS》1992,27(9):962-966
A series of new synthetic tetrabenzyl N-glucosidic, N-mannosidic and N-galactosidic isomers were investigated by fast atom bombardment (FAB)/mass-analysed ion kinetic energy (MIKE) spectrometry. The [M + H]+ ions were obtained with high abundance in the FAB spectra when using 3-nitrobenzyl alcohol as the matrix. The FAB/MIKE spectra provide characteristic daughter ions fragmented from selected molecular parent ions, allowing these isomers to be differentiated. In addition, an interesting rearrangement was found from the MIKE spectra, indicating that the benzyl (Bzl) group on the sugar ring is rearranged on to the N atom of the base (R) group to form [R + Bzl + H]+ and [R+ 2Bzl]+ ions. 相似文献
15.
Thitiporn Rungsimanon Apirat Laobuthee Mikiji Miyata Suwabun Chirachanchai 《Journal of inclusion phenomena and macrocyclic chemistry》2008,62(3-4):333-338
N,N-bis(2-hydroxyalkylbenzyl)alkylamine (HBA) is a derivative obtained from a single time ring opening of benzoxazines. For HBA with methyl group at ortho and para positions, and at N atom, the reaction between this derivative and ditosylated compound gives [1+1] dibenzo-monoaza-crowns. For HBA without methyl group at ortho position, the compound gives [2+2] macrocyclic ethers. The studies on inclusion phenomena using Pedersen’s and molar ratio techniques clarify the alkali metal ion guest inclusion to be 2:1 for [2+2] and 5:2 for [1+1] macrocycles. 相似文献
16.
R. Ghorbani-Vaghei S. Hajinazari M. Engashte 《Journal of the Iranian Chemical Society》2012,9(5):655-660
Poly(N,N??-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS] and N,N,N??,N??-tetrabromobenzene-1,3-disulfonamide[TBBDA] were used as efficient reagents for conjugate addition of indole and pyrrole with ??,??-unsaturated ketones and also, double-conjugate 1,4-addition of indoles to dibenzylidenacetones. 相似文献
17.
《Chemical physics》1986,101(2):299-309
Collision-induced dissociation of a 5–10 keV N2+ beam impinging on a helium target has been reinvestigated by translational spectroscopy. The laboratory kinetic energy distribution of N+ fragments exhibits height structures on a continuum. They correspond to N+ and N fragments ejected in the c.m. frame with kinetic energies W of 4.75, 6.4, 6.8 and 8.1 eV and they are interpreted as transitions into excited states of N2+ lying at more than 30 eV above the ground state of N2. The experimental W distribution extending over 12 eV is compared to distributions calculated using the model of vertical Franck—Condon electronic excitation with different assumptions for the initial and final states. 相似文献
18.
《Physics and Chemistry of Liquids》2012,50(3):383-399
Abstract Viscosities of aqueous solutions of formamide, N-methylformamide and N,N-dimethylformamide have been measured at temperatures 303.15, 308.15, 313.15, 318.15 and 323.15 K. For formamide + water system the viscosity increases exponentially with respect to the mole fraction of formamide. In contrast, N-methylformamide+water and N,N-dimethylformamide+water systems exhibit maxima in water-rich region, the maxima of the latter being higher and sharper than those of the former system. The excess viscosities of formamide+water system are positive at 323.15 K, which turn to negative values at 303.15 K, the magnitude of the values being very small irrespective of their sign. On the other hand, N-methylformamide+water and N,N-dimethylformaide+water systems show large positive excess viscosities for the whole range of composition. The viscosities and excess viscosities for the system formamide+water have been explained by assuming some complex formation between the components with the simultaneous disruption of water structures. For N-methylformamide+water and N,N-dimethylformamide+water systems, it has been assumed that cluster-like structure of water is formed around methyl group(s) attached to N-atom of the amides, which influences the viscosity behaviour of these systems strongly. 相似文献
19.
V. A. Tartakovskii A. S. Ermakov N. V. Sigai S. A. Serkov 《Russian Journal of Organic Chemistry》2006,42(7):949-953
New mixed plasticizers for gas-generating compositions on the basis of nitrooxy derivatives of N,N′-dialkyl-N,N′-dinitromethanediamines were obtained by condensation of N-hydroxyalkylsulfamates with formaldehyde, followed by nitration. 相似文献
20.
Bernice L. Kickel James B. Griffin P. B. Armentrout 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,24(2):101-110
Guided ion beam mass spectrometry is used to measure the cross sections as a function of kinetic energy for reaction of SiH4 with O+(4S), O 2 + (2Πg,v=0), N+(3P), and N 2 + (2Σ g + ,v=0). All four ions react with silane by dissociative charge-transfer to form SiH m + (m=0?3), and all but N 2 + also form SiXH m + products where (m=0?3) andX=O, O2 or N. The overall reactivity of the O+, O 2 + , and N+ systems show little dependence on kinetic energy, but for the case of N 2 + , the reaction probability and product distribution relies heavily on the kinetic energy of the system. The present results are compared with those previously reported for reactions of the rare gas ions with silane [13] and are discussed in terms of vertical ionization from the 1t 2 and 3a 1 bands of SiH4. Thermal reaction rates are also provided and dicussed. 相似文献