Compressibility of Liquids. Rule of Noncrossing V−P Curvatures

Weight analysis of the liquid introduced into the stainless steel bomb under pressures up to 1 kbar in the temperature range of 20-50 degrees C at the interval of 10 degrees C was performed for 1,4-dioxane, acetonitrile, toluene, ethyl acetate, chlorobenzene, and n-hexane. The coefficients of the Tait equation were determined for all of the solvents at each temperature. There was a clear linear relation between the tangent bulk modulus (1/beta T) at atmospheric pressure (1 bar) and the secant bulk modulus at 1 kbar; 1/betaT=0.9865 x (1000 V0/DeltaV(1kbar))-4559 was found at a wide range of temperatures for different liquids, including glycerol and even mercury. This represents the rule of noncrossing P-V curvatures for the liquids. Using the correlation, it is possible to predict the coefficients (C, B) of the Tait equation from the experimental data of betaT at 1 bar or, on the other hand, to calculate the value of betaT from experimental compression at high pressures.