Isothermal high pressure flow calorimeter

Abstract

An isothermal flow calorimeter suitable for measuring heats of reaction and heats of mixing at high pressure is described. With the calorimeter endothermic or exothermic processes can be studied from 0 to 70 °C and from 1 to 400 atm. Energy effects from 0.15 to 30 J/min are measured with a precision of ±0.4% at a constant temperature through the use of an automatic controlled variable heater and a constant cooling Peltier device. A complete heat‐of‐mixing curve can be generated from a single run. The calorimeter was tested by measuring the heats of neutralization of HClO₄–NaOH and HClO₄–TRIS and the heat of mixing of n‐hexane‐cyclohexane, and was found to produce data in very good agreement with published literature values.