The Vapor Pressure of Deuterium Water from 20 to 230°

Calorimetric measurements of the ratio of the heat evolved in the formation of 1 mole of liquid deuterium oxide, from gaseous deuterium and ordinary oxygen, to the heat evolved in the formation of 1 mole of ordinary liquid water, from gaseous ordinary hydrogen and oxygen, yielded the value 1.030 68 ± 0.000 29 for 25° C and a constant pressure of 1 atmosphere.Calorimetric measurements of the ratio of the heat of vaporization of 1 mole of deuterium oxide to that of 1 mole of ordinary water yielded the value 1.031 45 ± 0.00075 for 25° C and zero pressure. On the assumption that the bond energies in H~ and D, are the same, and likewise in H~O and D20, the difference in the zero-point energies of H~O(g) and D20(g) was calculated to be 14,841 ± 91 into j/mole (3,548 ± 22 cal/mole, or 1,243.0 ± 7.6 wave numbers). The accord of this value with that recently calculated by Darling and Dennison from the vibrational-rotational spectra of deuterium oxide and protium oxide, 1,245.5 ± 2.0 wave numbers, indicates that, within the assigned limits of uncertainty, the respective bond energies are independent of the mass of the nucleus of the atom .

“…From the data of Miles and Menzies [19] (see also Lewis and MacDonald [20]), the vapor pressure of liquid deuterium oxide at 25° C may be taken as 3. …”

mentioning

confidence: 99%

Heat and free energy of formation of deuterium oxide

Rossini¹,

Knowlton²,

Johnston³

1940

“…The ease and rapidity WIth which comparisons of boiling points can be made with precision, by means of the ebulliometric technique of ~wi~toslawski, suggests this method as a convenient analytical procedure for following the early stages in the production of heavy water. The linearity of the relation evidently extends through the entire range of composition since, by extrapolation of the straight line, or calculation from equation 1, a value of 101.41 ° C is obtained for the boiling point of pure D 20 as compared with 101.42° measured by Lewis and Macdonald [8], and 101.40± 0.016° C obtained by Miles and M enzies [11] from vapor-pressure measurements.…”

Section: Experimental Results and Conclusionmentioning

confidence: 65%

Boiling-point-composition diagram for dilute aqueous solutions of deuterium oxide

Smith¹,

Wojciechowski²

1936

The differences between the boiling points of dilute aqueous solutions of heavy water and the boiling point of ordinary water were measured in the range from 0.3 to 7 percent of D 20. The boiling p oints were found to increase linearly with increa se in D 20, according to the equation mole % of D20 = 70.9 (tJ.T), where tJ.T is the boiling point in degrees centigrade minus 100. The measmements, made with ebulliometers of the type devised by W. Swi~toslawski, were found to offer a. rapid method for the analysis of solutions of heavy water.The differences between the boiling points and condensation temperatures of the same solutions were measured in a differential ebulliometer which gave a fractionation equivalent to about one theoretical plate. The small separation between the vapor and liquid lines on the boiling-point-composition diagram shows that the separation of heavy water by fractional distillation would require columns of extremely high efficiency.

“…The rate of the conversion was controlled by the rate of input of energy into the bulb containing the liquid D 20 . From the data given in table 1, it appears that the vapor pressure of the deuterium oxide was somewhat above 1 atmosphere [8]. The pressure drop through the reaction tube (B in fig.…”

Section: Experimental Results and Conclusionmentioning

confidence: 95%

Method and apparatus for the rapid conversion of deuterium oxide into deuterium

Knowlton¹,

Rossini²

1937

A method and apparatus are described in detail for the rapid conversion of deuterium oxide into deuterium. A glass bulb at one end of the evacuated conversion apparatus contains a sealed ampoule holding the liquid deuterium oxide. This ampoule of deuterium oxide is broken by placing liquid air around the outer bulb, which is subsequently heated electrically to control the passage of the vapors of deuterium oxide into the reaction tube containing powdered magnesium at 480 0 C, where the following reaction occurs: Mg(snlid) + D20 (gas) = MgO (solid) + D2 (gas). The rate of evolution of deuterium from the I-inch reaction tube can be made as great as 1 mole in 2 hours. The evolved deuterium passes through a liquid-air filter-trap and is collected as liquid in a 50-ml brass bottle immersed in ordinary liquid hydrogen (temperature about -253 0 C). The connection to the conversion apparatus is closed, that to a I-liter brass bottle is opened, and the deuterium is permitted to vaporize and fill the two brass bottles at room temperature. In this manner 95 percent of the deuterium is obtained in the I-liter bottle as a gas under a pressure of about 23 atmospheres.