Heats of isomerization of the five hexanes

Abstract

A procedure is outlined and utilized for determining with high precision the ratios of the heats of combustion, and hence the heats of isomerization, of the five hexanes. In principle, the r atio of the heats of combustion of any two isomers was determined as the inverse ratio of the masses of carbon dioxide whose formation in the combustion of the respective hexanes produced identical increases of temperature in the calorimeter system, measured as an increase in the resistance of the platinum resistance thermometer.The following values were obtained for the liquid state at 25° C, and calculated to the gaseous state at 25° C and 0° K: Heat of isomerization, 6HFor n-CaHu=i-CaHu I somer Liquid Gas 25° C 25° C 0° K kcal/mole kcal/mole kcal/mole n-Hexane _________ ____ 0 0 0 2-Methylpentane ____

Some experimental data on the heats of combustion of benzoic acid and carbon (graphite)

“…The apparatus used in this work was the same as that described in references [4] and [5]. The calorimeter systems A, B, and a referred to in this report are identical with those described in reference [5].…”

“…The procedure followed in performing the calorimetric combustion experiments is described in detail on pages 302 and 303 of reference [4].…”

“…The products of combustion were examined as previously described [4]. No products of incomplete combustion were detected in the gaseous products from any of the experiments with benzoic acid or with graphite.…”

“…The samples were ignited in the bomb by a coil of 5 cm of Parr wire placed about 1 mm above the sample in the platinum crucible or dish [4].…”

“…The correction for the nitric acid formed in the reaction in the bomb was made as described previously [4,5).…”