Formamide physical properties

Tables 1 and 2 Hst the important physical properties of formamide. Form amide is more highly hydrogen bonded than water at temperatures below 80°C but the degree of molecular association decreases rapidly with increa sing temperature. Because of its high dielectric constant, formamide is an excellent ionizing solvent for many inorganic salts and also for peptides, proteias (eg, keratin), polysaccharides (eg, cellulose [9004-34-6] starch [9005-25-8]) and resias.

The physical properties of finish removers vary considerably due to the diverse uses and requirements of the removers. Finish removers can be grouped by the principal ingredient of the formula, method of appHcation, method of removal, chemical base, viscosity, or hazardous classification. Except for method of apphcation, a paint remover formulation usually has one aspect of each group, by which it can be used for one or more appHcations. A Hst of the most common organic solvents used in finish removers has been compiled (3). Many are mentioned throughout this article others include ethyl lactate [97-64-3] propylene carbonate [108-32-7] furfural alcohol [98-01-1/, dimethyl formamide [68-12-2] tetrahydrofuran [109-99-9] methyl amyl ketone [110-43-0] dipropylene glycol methyl ether [34590-94-8] and Exxate 600, a trade name of Exxon Chemicals. 

Only A/-vinyl-2-pyrrohdinone (VP) [88-12-0] is of significant commercial importance and hence is the principal focus of this article. Vinylcaprolactam is available (BASF) and is growing in importance, and vinyl formamide is available as a developmental monomer (Air Products). Some physical properties are given in Table 1. 

The physical properties of the anhydrate form and two polymorphic monohydrates of niclosamide have been reported [61], The anhydrate form exhibited the highest solubility in water and the fastest intrinsic dissolution rate, while the two monohydrates exhibited significantly lower aqueous solubilities. In a subsequent study, the 1 1 solvates of niclosamide with methanol, diethyl ether, dimethyl sulfoxide, N,/V -dimethyl formamide, and tetrahydrofuran, and the 2 1 solvate with tetraethylene glycol, were studied [62], The relative stability of the different solvatomorphs was established using desolvation activation energies, solution calorimetry, and aqueous solubilities. It was found that although the nonaqueous solvates exhibited higher solubilities and dissolution rates, they were unstable in aqueous media and rapidly transformed to one of the monohydrates. 

Table I lists the important physical properties of formamide.

ESR spectra, 511 Uranium(VI) complexes dioxoneocupferron, 512 Uranium hexaalkoxides physical properties, 347 Uranyl complexes cupferron, 512 formamide, 491 glycolic acid, 472 hexafluoroacetylacetone, 373, 377 photochemistry, 385 rearrangement, 384 maleic acid conformation, 467 neutral 1,3-diketones, 402 poly ketones, 399 Urea... 

PHYSICAL PROPERTIES colorless to white crystalline (sand-like) solid odorless solid soluble in water slightly soluble in ethanol moderately soluble in glycerol, glycol, liquid ammonia, and formamide MP (131°C, 268°F) BP (160°C, 320°F) DN (more than 1 at 20 C, solid) SG (1.77) VP (OmmHg at 20°C). 

PHYSICAL PROPERTIES white, crystalline solid faint, acrid odor very slightly soluble in water soluble in ethanol, heptane, chloroform, xylene, acetone, and dimethyl-formamide MP (300 C, 572°F) BP (decomposes) DN (data not available) SG (data not available) VD (data not available) VP (<0.1 mmHg at 20 C). 

PHYSICAL PROPERTIES colorless to white, crystalline powder crystals are ditetragonal soluble in water soluble in ethanol, ethylene glycol, glycerol, and formamide insoluble in benzene, acetone, carbon tetrachloride, paraffins, ether and petroleum ether MP... 

PHYSICAL PROPERTIES clear, colorless liquid heavy, mobile liquid chloroform-like odor very slightly soluble in water miscible with methanol, ethanol, carbon tetrachloride, benzene, ether, petroleum ether, carbon disulfide, chloroform, dimethyl formamide, and... 

Table 21. Some Physical Properties of Formamide and Acetamide...

Among different citrates, differences in indices of refraction are very small in dilute solutions, for m < 0.5 mol kg , but they are clearly evident with increasing concentratioa Other physical properties of citrate solutions are only sporadically reported in the literatme. Usually, they are by-products of investigations, rarely dealing with the concentration or temperature dependence. It is possible to mention here only measurements of surface tension of tripotassium citrate performed by Livingston et al. [200] and Lu et al. [180] and the Bhat and Manjunatha [201].determinations of electrical conductivities of citrates in the water + dimethyl formamide mixtures (Table 5.17). 

Aprotic electrolytes based upon methyl formate, propylene carbonate and dimethyl formamide as solvents and lithium chloride plus aluminum chloride, lithium hexafluoroarsenate and lithium perchlorate as solutes are discussed. The effect of additives, other aprotic solvents, other salts and trace amounts of water on species in solution and other physical properties are described. 

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