EXCESS-ENTHALPIES FOR (WATER PLUS BENZENE) IN THE LIQUID AND SUPERCRITICAL REGIONS AT T=503-K TO T=592-K AND P=16.4-MPA

Flow calorimetric measurements of the excess molar enthalpy H-m(E) of {xH(2)O+(1-x)C6H6} measured at the pressure 16.4 MPa are reported. Mea surements made at the temperatures (503, 521, 544, and 560) K are in a region of the phase diagram which shows partial miscibility of the tw o liquids. Measurements made at the temperatures 576 K and 581 K are i n a homogeneous fluid region, and measurements made at T = 592 K cross a liquid-vapour two phase loop at x > 0.75. The H-m(E)(x) diagrams al l show linear behaviour where two phase regions are crossed, and the e xtrema of these linear sections gives information about the location o f phase boundaries. Values of H-m(E) at x = 0.5 are shown to lie on cu rves which are a continuation into the liquid phase region of vapour p hase H-m(E) (x = 0.5) measurements published previously. The measureme nts are compared with the cubic equation of state of Patel and Teja. T he equation generates H-m(E)(x) isotherms which have the correct shape and which are closer to the experimental measurements at high tempera tures than at low temperatures. (C) 1996 Academic Press Limited