화학공학소재연구정보센터
Journal of Chemical Physics, Vol.108, No.22, 9537-9539, 1998
Coexistence curve of perfluoromethylcyclohexane+carbon tetrachloride near the critical point in composition-pressure and composition-temperature space
Coexistence curves in volume fraction-temperature (phi-T) space and in volume fraction-pressure (phi-p) space have been measured for the binary system perfluoromethylcyclohexane+carbon tetrachloride in the temperature range T-c-T<0.8 K and in the pressure range p-p(c)<3.2 MPa near the critical point (T-c,p(c),phi(c),). The observed coexistence curves were expressed by the simple scaling relation phi(+)-phi(-)=B-T(T-c- T)(beta T) in phi-T space and by phi(+)-phi(-)=B-p(p-p(c))(beta p) in phi-p space. The exponent was determined as beta(T)=0.326+/-0.001 and beta(p)=0.330+/-0.006, which agree with each other and with the theoretical value beta=0.327 for the Ising model. The observed coefficients give (B-p/B-T)(1/beta) = 0.42 +/- 0.02 K/MPa, which may be compared with the slope (dT/dp)(c) = 0.38 K/MPa of the p-T critical line in light of a thermodynamic argument. This means that the pressure range is converted into the temperature range with the slope (dT/dp)(c) as a scale factor.