Vapor-liquid and liquid-liquid equilibrium compositions and critical points were measured for the dodecane-water and squalane-water systems at temperatures from 600 to 660 K and pressures up to 310 bar. A continuous-flow apparatus was used for these high-temperature measurements to minimize thermal decomposition of the hydrocarbons of interest. Both systems were found to exhibit Type III phase behavior, with the critical curve that starts from the critical point of water passing through both temperature and pressure minima before extending to higher pressures. A limited number of liquid-liquid equilibrium compositions are also reported for the benzene-water system at temperatures from 472 to 523 K.