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The vapor pressures of dimethyl sulfoxide and hexadeuterodimethyl sulfoxide from about 313 to 453 K

1972; Elsevier BV; Volume: 4; Issue: 6 Linguagem: Inglês

10.1016/0021-9614(72)90007-9

1096-3626

G. Jákli, W. Alexander Van Hook,

Inorganic Fluorides and Related Compounds

The vapor pressure of (CH3)2SO has been determined from 323 to 443 K by mercury manometry thereby extending the older (293 to 323 K) results of Douglas. A least-squares fit was made to the available data and is suitable from approximately 291. 7 K (the melting temperature) to 463 K, and is ln(pTorr) = 17.4922 – 4517.79(TK − 47.2583). The vapor pressure difference, [p“(CD3)2SO’ − p“(CH3)2SO’], was measured by differential capacitance manometry between 323 and 368 K, and by mercury manometry between 383 and 463 K. The vapor pressure isotope effects derived from the results may be expressed by the equation: ln(pDpH) = −43454.6(KT)2 + 219.449(KT) − 0.25996. The isotope effect on the melting temperature Tm was determined as Tm“(CD3)2SO’ − Tm“(CH3)2SO’ = (2.30 ± 0.02) K, substantiating the prediction (above) of a change in sign of the isotope effect around 313 to 318 K.