Pressure of Deuterium Oxide

The deuterium content can be determined by reaction of the deuterated diazomethane with benzoic acid-O d in anhydrous ether followed by analysis of methyl benzoate for deuterium content either by n.m.r. spectrometry or by mass spectrometry. The benzoic acid-O-d is prepared by heating a mixture of 48.6 g. (0.216 mole) of benzoic anhydride (obtained from Aldrich Chemical Company, Inc.), 0.10 g. (0.0009 mole) of anhydrous sodium carbonate, and 7.0 g. (0.35 mole) of deuterium oxide to 90° for 2 hours. The resulting mixture is distilled at atmospheric pressure in a short-path still fitted with a receiver protected from atmospheric moisture by a drying tube. After removal of a forerun, b.p. 100-101°, the benzoic... 

Triatomic Gases.—Kell et al measured mass, p, and T of water vapour in a nearly constant volume for various temperatures between 150 and 450 C, and pressures in the range 0.6 to 94 bar. They calculated B, C, and A and expressed B and C as functions of T. The same workers carried out a similar study of deuterium oxide vapour, the range of variables being 150 to 500 °C and 1.0 to 101 bar. They calculated B and C, and showed that B for D2O is very slightly more negative than B for HgO. 

In reeent years, tire use of elevated temperatures has been reeognised as a potential variable in method development. Witlr inereased temperature, aqueous-organie mobile phases separations ean improve, viseosity deereases and diffusion inereases so baek pressures are redueed. At higher temperatures (usually with superheated water > 100 °C under modest pressures) water alone ean be used as the mobile phase and eair provide unique separation opportunities. The absenee of an organie solvent enables the use in HPLC of alternative deteetors sueh as FID or on-line LC-NMR using deuterium oxide as the eluent. 

Tetraethyl orthosilicate (104.2 g) and deuterium oxide (40 g) are stirred in a stoppered distillation flask at room temperature until a viscous, miscible solution is obtained (approximately 24 hr). (A small amount of acid catalyst, such as deuteriochloric acid, speeds up the reaction considerably. ) A distillation head and a receiver cooled in a dry ice-acetone bath are attached and the solution is distilled at 2 mm pressure until no further product is obtained. A 90% yield of ethanol-OD is obtained having an isotopic purity equal to that of the deuterium oxide used. ... 

The estimation of flow functions from an actual experiment is reported next. A multi-rate primary drainage experiment was conducted on a Texas Cream limestone sample. Hexadecane was used as the oleic phase and deuterium oxide (D20) was used as the aqueous phase. Protons are imaged, so only the oil phase is observed. The pressure drop data, production data and saturation data are shown in Figures 4.1.11-... 

Snyder AP, Harden CS. 1990. Determination of the fragmentation mechanisms of organophosphorus ions by water and deuterium oxide atmospheric-pressure ionization tandem mass spectrometry. II. Dialkylphosphonate ions. Org Mass Spectrom 25(6) 301-308. 

Over small ranges of temperature (not more than 10 ) the vapour pressures may be interpolated logarithmically as follows at 10°, p=9 205 mm. and log p=0 96402, at 11°,/7=9 840 mm. and log / =0 99299 difference for 1°= 0-02897, for 0-1° 0-0029, for 0-6° 0-01740 logp at 10-6°=0-98142, p=9-581 mm. For large temperature differences a vapour pressure formula ( 18-21,VIIIJ) should be used. Vapour pressures of heavy water (deuterium oxide D2O) are smaller than those of ordinary water. 1 The vapour pressure of mercury is particularly important and has often been determined some values are given below ( °C.) ... 

Quinazoline is deuterated preferentially in positions 2 and 4 on heating with deuterium oxide and platinized short-fibre asbestos (Caution carcinogenic) in a sealed tube or pressure vessel at 130 250 C. ° Deuteration of 7-amino-6-nitroquinazolin-4(3/y)-one (1) in [ Hjmethanol under reflux yields product 2 deuterated in position 8, whereas in 6,7-diaminoquinazolin-4(377)-one (3), on treatment with deuterium oxide in dimethylformamide, 5H and 8H are exchanged for deuterium to give the deuterated derivative 4. ° ... 

F.H. Hambleton, l.A. Hockey, and l.A.G. Taylor, An Infra-red Investigation of the Effect of Pressure on Silica Powders, as Revealed by Deuterium Oxide Exchange, Nature, 208, pp. 138-139, 1%5. 

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