Notes 2773 F HgFz I CHjCN -> CH8C=NF + other products Experimental Dichloromalononitrile and N-l, 1-TrichlorocyanoacetimidoylChloride.-A solution of 33.0 g. of malononitrile (0.5 mole) and 500 ml. of water was added to a 1-1. flask equipped with stirrer, thermometer, Dry Ice-acetone reflux condenser, inlet tube, and external ice-water cooling bath. Chlorine gas (118.3 g., 1.67 moles) was introduced slowly with stirring over a period of 4 hr., taking care to keep the temperature at or below 5°. The cooling bath was removed and the stirring was continued another 3 hr., during which time the upper portion of the flask was heated gently with warm air in order to decompose the solid chlorine hydrate. The reaction mixture was then separated. The upper aqueous phase was evaporated to 3.2 g. of white solid, identified as ammonium chloride by infrared spectrum. It gave positive tests for ammonia and chloride ion. The lower, organic phase was fractionated. At atmospheric pressure, 46.9 g. of dichloromalononitrile was collected at 86-93°, with an additional 3.0 g. at 41°when the pressure was reduced to 105 mm. The total yield amounted to 74.0% based on malononitrile. Continuation of the distillation at 45 mm. yielded 8.9 g. (8.5% of theory) of N-l, 1 -trichlorocyanoacetimidoyl chloride boiling at 93-97°.Redistillation at 45 mm. furnished pure material at 97°.

No abstract

Study of the diffusion in polymers of molecules comparable in size and structure to the segments of the chain molecules is suggested as a means of securing information on structure and molecular friction forces in polymers. A convenient method for measuring the diffusivity in polymers of such compounds tagged with C‐14 was devised and used to study the diffusivity of octadecane, octadecanol, stearic acid, and octadecyl stearate for a range of temperatures in polymers including natural rubber, GR‐S, polybutadiene, polyisoprene, and polyisobutylene. Diffusivities were independent of concentration for the range used. The diffusivities of straight chain hydrocarbons in natural rubber appear to vary inversely as the molecular weight of the diffusing compound. Evidence was found for association effects in the diffusion of stearic acid in natural rubber. Activation energies for diffusion of the compounds were quite similar in any one polymer and of the same order as reported for low molecular weight hydrocarbons and for viscous flow. Larger differences in activation energies were observed for diffusion in the different polymers. Correlations were observed for the diffusivities of octadecane in a series of polymers with their densities and thermal expansivities, especially the latter. Some study was given to the effect on the diffusivity of octadecane of such parameters as polymer unsaturation, solution viscosity, molecular weight, and crosslink density. The diffusivity of octadecane in natural rubber had a pronounced maximum as a function of crosslink density, coinciding with the maximum in tensile strength. Possible implications of this are discussed. The diffusivities of octadecane in a series of elastomers were studied in relation to the internal frictional losses observed for 60 cps vibrations over a range of temperatures. It was concluded that frictional forces deduced from the diffusivity measurements have some correspondence to high frequency viscoelastic phenomena which involve small units of structure comparable in size to the segments of the polymer molecules.

No abstract