In the design of chemical equipments, thermodynamic properties of pure forms and mixtures are very important. For the systems selected, the experimental works were carried out in two phases—experiments of enthalpy of mixing, and heats of vaporization were conducted. From the various designs available for the experimental determination of enthalpy of mixing, the apparatus described by Tanaka et al. (1972), Patel (1974) and Nirguna Babu (2003), was selected, modified and fabricated. Experiments were conducted in the equipments designed for the mixtures of Ethyl alcohol with n-Hexane and n-Heptane. Data on heats of vaporization were obtained by using a static apparatus similar to the one used by Rao and Viswanath (1973). The apparatus selected was modified, fabricated and tested for accuracy. Experiments were conducted for the mixtures of Ethyl Alcohol with n-Hexane and n-Heptane.

Enthalpy of mixing refers to change in the enthalpy per mole of solution formed when pure components are mixed at the same temperature and pressure. Enthalpy effects on mixing of liquids are quite large and of considerable importance, especially in case of the design of absorption and distillation columns. Heat of vaporization is the amount of heat required to change a unit amount of liquid at bubble point (saturated liquid) to a vapor at its dew point (saturated vapor). Heats of vaporization data are useful in the determination of heat loads in distillation columns.

In the present work, the experimental determination of enthalpy of mixing and heats of vaporization for the mixtures of Ethyl Alcohol with n-Hexane and n-Heptane are taken up.

The schematic diagram of the apparatus used for enthalpy of mixing is shown in Figure 1. It consists of a cylindrical Dewar flask of inner diameter 55 mm and 113.7 mm height. The space between the wall of the calorimeter and the jacket is evacuated to 10^-4 mm Hg. The total volume of the flask is 270 cc. The top section of the calorimeter has provisions for inserting the transducer AD590 (temperature sensing device), a nichrome heater, a stirrer and two openings to feed the two liquid components. The stirrer is of paddle type and there are two paddles fixed at an equal distance of 15 mm from the bottom as suggested by Uhl and Gray (1967) and Perry and Green (1998). The stirrer passes through a teflon joint with O-ring seal. Transducer AD590 and nichrome heater are inserted through B-14 ground glass joints. Two B-14 joints are provided on the calorimeter to feed the two liquid components that are in the jacketed burettes. A capillary tube of 85 mm height and 0.1 mm diameter is fused to the top section of the calorimeter to eliminate the pressure build up in the calorimeter and to conduct the experiment at local atmospheric pressure. A temperature sensing device transducer AD590, with an accuracy of ±0.05 ^°C, embedded in the glass tube is used.

Chemical Engineering Journal, Enthalpy of Mixing, Heat of Vaporization, Ethyl Alcohol, n-Hexane and n-Heptane, Chemical Equipments, Thermodynamic Properties, n-Hexane-Ethyl Alcohol System, Vapor-Liquid Equilibrium, VLE, Thermodynamic Properties, Binary Mixtures.