employed by Tourky, llizk, and Girgis. The value obtained, 1.88D, agrees reamiably well with their value, 1.93D, and also with the generally accepted gas moinent value, 1.84D. This supports the conclusion that water behaves in a nonassociated manner in dilute soliitionq in p-dioxane. The slope obtained from present data for witer concentrations below 1% is very sindar to that obtained by Tourky, Rink, and Girgis at higher concentrations. Therefore, relatively simple differential determinations of dielectric constant can be used successfully t o ana yze for small amounts of water in p-dioxane solutions or extracts. Apparently a similar procedure can be used uith biq(2-ethoxydhyl) ether. ACKNOWLED SMENT
The measuring cells and &-meter were calibrated by the Dielectrics Section, Electricity IXvision, of the
Kational Bureau of Standards. The author especially acknowledges the valuable advice and assistance of Arnold H. Scott and William P. Harris who collaborated in the design of the measuring cells and performed precipe d i b r a t i o n s on them. LITERATURE CITED
(1) Akerlof, G., Short, 0. A., J . Am. Chem. SOC.58, 1241 (1936). (2) Bouyoucos, G. J., Science 67, 167
(1928). (3) Breen, S. (to Forte-Fairbairn, Inc.), U. S. Patent 3,012,193(Dee. 5, 1961). (4) Cashmore, TTT. H., “A Rapid Method for Measuring the Moisture Content of Wheat,” Inst. for Res. in Agr. Eng., Oxford, England, 1933. ( 5 ) Critchfield, F. E., Gibson, J. A., Jr., Hall, J. L., J . A m Chem. SOC. 75, 1991 (1953). (6) Dasler, TV., Bailer, C. n., IND.E X G . CHEM.,A4SA1J. ED. 18, 52 (1946). (7) Elliott, RI. A., Williams, J. JV., J . Am. Chem. SOC.61,718 (1939). (8) Hancock, C. K., Burdick, R. L., J .
Am. Oil Chemists’ SOC.33, 175 (April
1956).
(9) Hart, J. R., Neustadt, & H., ‘ICereal . Chem. 34, KO.1, 26 (1936). (10) Mannheimer, Rf., ISD. ESG. CHEM., ANAL.ED. 1, 154 (1929). (11) Maryott, 8.A, Smith, E. R., “Table
of Dielectric Constants of Pure Liquids,” NBS C‘zrc. 514,Atg. 10, 1951. (12) Oehme,,, F., Dielektrische blessmethoden, Monograph No. 70 for Angew. Chem. and Chem Ing.-Tech., Verlag Chemie, 1958. (13) Oehme, F., Farbe Lack 66, No. :> R,. The injection is performed by rapidly immersing the needle below the solution level (to avoid bubbles) and rapidly injecting. The mixing time is fast (-3 seconds) compared to reaction rate. The opposite order of addition (reagent added to sample solution) is also employed. The reaction is allowed to run t o Procedure.
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