各種の油脂とn-ヘキサンとよりなる系の混合熱と粘性係数

抄録

The change of heat due to mixing n-hexane with various fatty materials, such as fatty oils, soybean oil fatty acid, and soybean oil fatty acid methyl ester, has been measured at 30.0°C in the whole range of concentration by direct calorimetric method. In all cases, heat is absorbed and the value of heat change due to mixing is highest at about 1 : 1 mixture of fatty material and nhexane by weight. The maximum value of heat of the mixing is as follows : soybean oil -0.48, rapeseed oil -0.55, camellia oil -0.62, olive oil -0.64, cocoanut oil -0.67, soybean oil fatty acid -0.26, and soybean oil fatty acid methyl ester -0.67cal/g-mixture, respectively.
The viscosity coefficient η of these mixtures has also been measured at 30.0°C in the whole range of composition. Logarithmic plot of viscosity coefficient for every mixtures as a function of mole fraction of fatty material, falls on upper-side of the straight line which is drawn to pass through the point of log η of each component. From these curves of viscosity coefficient versus mole fraction, the parameter “q”, which indicates the shape of the molecule of fatty material in the mixture, can be calculated, provided that the quasi-crystalline model is to be maintained. Furthermore, the coordination number “z” in the mixture can be estimated, and it is found that the value is to be about eight in all these mixtures.
Combining the parameter “q” with the heat of mixing “Δ_mH”, expressed in cal/mole-mixture, interchange energy “N_w” between fatty material and n-hexane can be calculated. The interchange energy has value of about +260cal/mole for all fatty oils and for fatty acid methyl ester, but has smaller value of +120cal/mole for fatty acid.
Using the values of “q”, “N_w” and “r” which represents the ratio of molar volume of fatty material to that of n-hexane, vapor pressure of n-hexane in the mixture can be calculated. But, if one takes the value of “N_w” found above, higher values of vapor pressure will be obtained than the values measured by experiment. This difference between experiment and calculation may be caused by the fact that the great contraction of volume occurs in the course of mixing. Then, if one takes the value of “N_w” multiplied by the factor of 0.7, calculated value of vapor pressure of n-hexane in the mixture will agree with experimental one.