Showing papers on "Ionic liquid published in 1977"

The synthesis and thermolysis of imidazole quaternary salts

Abstract: The pyrolysis of imidazolium halides substituted on the nitrogen atoms by alkyl or aryl groups leads to 1-substituted imidazoles. Differing substituents cleave at different rates, while the nature of the anion and the influence of substituents at C4 modify the reaction products. Tetraphenylborate and perchlorate salts fail to dealkylate. An SN2 (or SN2?) mechanism appears to be the most likely for the process.

Structural and spectral studies of halogeno complexes of rhodium(III)

Abstract: Halogeno complexes of rhodium(III) of the type A2 [RhCl5H2O], A3 [RhCl6],H2O and A3 [Rh2X9] (X = Cl, Br, A = alkali metal, ammonium and alkylammonium cations) have been prepared and investigated structurally by X-ray powder photography, and by infrared and visible spectroscopy. The relationship between the various preparative procedures has been determined. Factors such as acidity and type of cation are important. Structural and spectroscopic studies have revealed trends which, in some cases, can be related to the influence of the cations on the halogenorhodate(III) anions in the solid state, and, in other cases, to the ionic/covalent nature of the metal-halogen bond.

On the nature of molten CuCl

Abstract: A recent suggestion that molten CuCl is a covalent molecular liquid (ibid., vol.8, p.895 (1975)), is contradicted by NMR relaxation time measurements of the Cu and Cl nuclei in this system. Rather the data are consistent with an ionic liquid description.

(Z)- and (E)-3,3'-(1,2-Ethenediyl)bispyridines

Abstract: (Z)-3,3?-(1,2-Ethenediyl)bispyridine has been prepared by decarboxylation of (Z)-2,3-di(3-pyridyl) acrylic acid and converted into (E)-3,3?-(1,2-ethenediyl)bispyridine by heating in nitrobenzene in the presence of iodine.

Hydroxyisothiazoles. II. Preparation of isothiazolin-3-ones and their methylated derivatives from the oxidation of cyano-substituted dithioacetate salts

Abstract: The hydrogen peroxide oxidation of α-cyanoaryldithioacetate salts (3) affords substituted isothiazol-3-ols (isothiazolin-3-ones) (4) in moderate yields. Methylation of the products yields mainly N-methyl derivatives. 4-Arylisothiazol-3-ols can be further oxidized to saccharin analogues (7).

Formic acid solvent system. II. Conductance and solvation studies of 1:1 electrolytes in formic acid

Abstract: Conductances of some 1 : 1 electrolytes have been measured in the concentration range (5-100) x 10-3 mol l-1 in anhydrous formic acid at 25°. The conductance data have been analysed by Fuoss-Shedlovsky equations. Transference numbers of sodium and potassium formates have been measured in this solvent at 25° by a modified Hittorf's method in the concentration range (3-80) x mol l-1. Ionic mobilities, effective ionic radii and solvation numbers of various ions in solution have been calculated. Solvation of cations decreases with the increase in the crystal radii of the ions.

Hydroxyisothiazoles. I. Preparation of 3- and 5-isothiazolinones by nucleophilic displacement of isothiazole sulphones

Abstract: Heating of 4-aryl-3,5-bis(alkylsulphonyl)isothiazoles with sodium hydroxide solution under reflux affords in good yield a readily separable mixture of the 3-hydroxy-5-alkylsulphonyl and 5-hydroxy-3- alkylsulphonyl compounds.

Fluorine magnetic resonance studies. IV. α,2-Difluoro- and α,α,2-Trifluoro-toluenes

Abstract: Fluorine-fluorine coupling over four bonds has been observed in the 19F N.M.R. spectra of three α,2-difluorotoluenes and three α,α,2- trifluorotoluenes.

Acetolysis and thermolysis of 2-nitrosoiminothiazolidines

Abstract: 2-Nitrosoiminothiazolidine (1) with acetic anhydride and pyridine gives thiazolidin-2-one, 3-acetylthiazolidin-2-one and 2-thiocyanatoethyl acetate. Thermal decomposition of (1) and of its 3-methylderivative (2) forms thiazolidin-2-ones.

Base decomposition of dichromate

Abstract: The rate of decomposition of dichromate, Cr2O72-, to form chromate, CrO42-, is very dependent upon the choice of cation, and its concentration. At a total ionic strength of 1.0 mol l-1 and at 25.0°C, the second-order rate constant decreases in the order Ca2+ (2600 mol-1 l. s-1) >> K+ + (960) > Na+ (920) >Li+ (700)>> bistet2+ (410) >> Me4N+ (125) >> Et4N+ (35) where bistet2+ is the N,N,N,N',N',N'-hexamethylethylene-1,2-diammonium ion. In the presence of sodium chloride the second-order rate constant increases as the ionic strength increases (200 and 1900 mol-1 l. s-1 at ionic strengths of 0 and 2.7 mol l-1 respectively), whereas in tetramethylammonium chloride a maximum is reached at intermediate ionic strengths. The equilibrium between dichromate and hydrogen chromate is shifted towards the dichromate side in the presence of tetraalkylammonium ions, and towards the hydrogen chromate side in the presence of calcium ion.