Dimethylformamide refractive index

Aminabhavi, T.M. and Patil, V.B. Density, viscosity, refractive index, viscosity, and speed of sound in binary mixtures of ethenylbenzene with 7V,7V-dimethylacetamide, tetrahydrofuran, 7V,7V-dimethylformamide, 1,4-dioxane, dimethyl sulfoxide, chloroform, bromoform, and 1-chloronaphthalene in the temperature interval (298.15-308.15) K, J. Chem. Eng. Data, 43(4) 497-503, 1998. 

Linoleic Acid occurs as a colorless to pale yellow, oily liquid that is easily oxidized by air. It is an essential fatty acid and the major constituent of many vegetable oils, including cottonseed, soybean, peanut, corn, sunflower seed, safflower, poppy seed, and linseed. Its specific gravity is about 0.901, and its refractive index is about 1.469. It has a boiling point ranging from 225° to 230° and a melting point around -5°. One milliliter dissolves in 10 mL of petroleum ether. It is freely soluble in ether soluble in absolute alcohol and in chloroform and miscible with dimethylformamide, fat solvents, and oils. It is insoluble in water. 

Gel Permeation Chromatography - The GPC data were obtained in dimethylformamide solution using a Waters Associates Model 100 GPC equipped with a differential refractive index detector and five Styragel columns having he following nominal exclusion limit designations 10 10 A, 10 A, 3 x 10 A,... 

Considering ion-solvent interactions other than hydrogen bonding, we expect ion-dipole forces to be stronger for cations, which are attracted by the exposed negative end of the CH3CN dipole, than for anions. Acetonitrile, to judge by its refractive index, is less polarisable than dimethylformamide, more nearly comparable with methanol. Dispersion interactions in acetonitrile will therefore be appreciable but not as prominent as in dimethylformamide. 

Here Y denotes a general bulk property, Tw that of pure water and Ys that of the pure co-solvent, and the y, are listed coefficients, generally up to i=3 being required. Annotated data are provided in (Marcus 2002) for the viscosity rj, relative permittivity r, refractive index (at the sodium D-line) d. excess molar Gibbs energy G, excess molar enthalpy excess molar isobaric heat capacity Cp, excess molar volume V, isobaric expansibility ap, adiabatic compressibility ks, and surface tension Y of aqueous mixtures with many co-solvents. These include methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-2-propanol (tert-butanol), 1,2-ethanediol, tetrahydrofuran, 1,4-dioxane, pyridine, acetone, acetonitrile, N, N-dimethylformamide, and dimethylsulfoxide and a few others. 

Gel permeation chromatography was carried out at 80 C with 0.05 M lithium bromide in dimethylformamide as eluent on a Waters Associates chromatograph with 10 , 10 , and 50 A i-Styragel columns. The system was equipped with a refractive index detector and was calibrated with narrow distribution polystyrene standards. Results are expressed, therefore, as polystyrene-equivalent molecular weights. 

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