Increase of the Percentage of Diplogen in Water during very slow Evaporation


IT is known that one of the methods of separating heavy water consists in the fractional distillation of ordinary water. I find that relatively strong enrichment of diplogen occurs during the slow evaporation of water. About three years ago a bottle containing 25 litres of distilled water was prepared for an experiment. The bottle was not used, and the water slowly evaporated leaving about 600 c.c. residue. The measurements showed that this water had a density of 1.0016 (4° C.). For comparison, I have evaporated by boiling a certain quantity of water to 1/60 of its initial volume. The residue had, however, a density of 1.0001. It is evident, therefore, that the action of slow evaporation is more efficacious than the action of boiling.


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    H. A. McKay, NATURE, 133, 611, April 21, 1934. E. W. Washburn, E. R. Smith, Science Abstracts (S.A.), 37, 434; 1934. E. S. Grifilan Jr., J. Amer. Chem. Soc., 56, 406; 1934.

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TUCHOLSKI, T. Increase of the Percentage of Diplogen in Water during very slow Evaporation. Nature 134, 29 (1934).

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