Thermal Data on Organic Compounds. XII. The Heats of Combustion of Nine Hydrocarbons

Abstract

Heats of Combustion of Some Hydrocarbons 3223 DiscussionThe values in Table I are slightly higher than the average of previously reported data. Our data also show a small, but persistent, difference in the solubilities of the samples. The larger solubility of samples 3 and 4 is most likely due to the more perfect development of these crystals resulting from the slower rate of precipitation used in their preparation.Considering the temperature difference the data of Table II are in good agreement with those of Huybrechts and Ramelot2b and Pleissner.3

Symposium on Fundamental Chemical Thermodynamics of Hydrocarbons and their Derivatives: Heat of Formation of Gaseous Hydrocarbons.

“…Unfortunately, however, no heats of vaporization of hydrocarbons above pentane have heretofore been measured at or near 25°C., and values calculated for this temperature, either from calorimetric data at the normal boiling point or from existing data on the vapor pressure-temperature relations, introduce an additional uncertainty into the values so derived for the heats of formation in the gaseous state. 2 The following symbols are used to designate the physical state of a substance: c = crystal; liq = liquid; g = gas. For paraffin hydrocarbons in the gaseous state, measurements of the heat of combustion were made on the following: methane (26), ethane (27), propane (27), «-butane (27), isobutane (30), «-pentane (27), 2-methylbutane (19, 39), and tetramethylmethane (19).…”

Heats of Combustion of Organic Compounds

“…The heat of combustion for the methylene ( -CH2 -) group was computed from heats of combustion of successive members of homologous series of straightchain dicarboxylic acids (67) and their dimethyl esters (66), normal primary aliphatic alcohols (65), and monoalkylsubstituted malonic acids (64). Much the same thing was done for paraffin hydrocarbons (7), and for aliphatic monocarboxylic chloroacids and their esters (57), in which the energy of cleavage of the C-Cl link was related to the change in position of the halogen.…”

Heats of combustion of the liquid normal parafin hydrocarbons from hexane to dodecane

“…Banse and Parks [1] in Roth's laboratory made three measurements of the heat of combustion of n-octane and four measurements of the heat of combustion of n-dodecane. The samples used were prepared by Shepard, Henne, and Midgley [20], and were therefore probably identical with the samples of n-octane and n-dodecane used in the present work.…”