The isothermal displacement
calorimeter described previously has been modified by the inclusion of a
thermoelectric cooling module to allow the study of both endothermic and
exothermic mixing. Other modifications are also described. Excess enthalpies
are reported for 1,4-dioxan+tetrachloro-methane, benzene+dichloromethane,
tetrahydrofuran+water, and ethanol+water at 298.15 K and 1,4- dioxan+dichloromethane
at 298.15 and 303.15 K. These mixtures have been suggested as possible
reference mixtures for either checking the operation of, or calibrating,
calorimeters to be used for making measurements on exothermic mixtures. The
performances of our calorimeters have been evaluated on the basis of the results
presented here and by comparison with previous results. Some advantages and
disadvantages of the proposed reference mixtures are discussed. Photochemical
effects from the tungsten thermostat lamp affect the results for mixtures of
tetra-chloromethane with 1,4-dioxan.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.