Design and testing of a microcalorimeter with semiconductor thermopiles as temperature sensor and study of the inclusion of Cu(II) with β-cyclodextri

Abstract

In this investigation, a microcalorimeter has been designed and tested which is primarily intended for studying heats of reaction in dilute solution at room temperature to 40° C. This microcalorimeter uses semiconductor thermopiles as the temperature difference sensor. Electrical calibration experiments and property testings indicate that the precision of the microcalorimeter is 0.3% for heat changes of about 2 J. The sensitivity is 170 μV mW −1; the time constant is 260 sec. The enthalpy of neutralization of TRIS with standard HCl solution has been measured. At 25°C, Δ H = −47.48±0.16 kJ mol −1, at 30°C, Δ H = −47.08 ± 0.26 kJ mol −1: these results are in good agreement with values given in the literature. Using this microcalorimeter the enthalpy of the inclusion reaction of β-cyclodextrin with Cu(II) in dilute solution was measured and a value of Δ H = −184.2 ± 0.7 kJ mol −1 obtained at 30.0°C.