Heats of combustion and isomerization of the six C7H14 alkylcyclopentanes

Abstract

The heats of isomerization of the ix C7Hu alkylcyclopentalles were determined by measurement of the ratios of th e heats of co mbustion of purified sampl es of these compounds in t he liquid state by t he procedure previously described for other iso meric hy drocarbons. The data yield thc following values for t he heat of isomcrization, !> 1I0, in the liquid state at 25° C, of ethylcyclopentane into each of the dimethyleyclopentanes, in kilocalori e per mole: Ethyleyclopentane, 0.00; 1,1-dimethyleyclopentanc, -2.06 ± 0.12 ; cis-1,2-dim ethylcyclopentane, -0.44 ± 0.20; trans-1,2-dimethylcyclopentane, -1.86 ± 0.16 ; cis-l ,3-dimethylcyclopentane, -1. 11 ± 0.24; trans-l,3-d imethylcyclopentane, -1. 60 ± 0.1 4. Th e e val ues were combi ned with valu es for t he differences in t he heats of vapori zation of these isomers to obtain value for the heats of isomerization in t he gaseo us state at 25° C.Uti li zing the values previously reported for the h eats of com b ust ion and formation of ethylcyclopentane in the liquid and gaseo us states at 25° C, values weTe calcu lated for the heats of combustion and formation of the five dimethylcyclopentales in the liquid and gaseous states at 25° C.

Gas-Phase Heat of Formation Values for Buckminsterfullerene (C60), C70 Fullerene (C70), Corannulene, Coronene, Sumanene, and Other Polycyclic Aromatic Hydrocarbons Calculated Using Density Functional Theory (M06 2X) Coupled with a Versatile Inexpensive Group-Equivalent Approach

“…The experimental Δ f H ° g,298 values used for several PAHs in the test set were those that had been critically evaluated by Roux et al for which there is general agreement with regard to their accuracy. Other Δ f H ° g,298 values for compounds included in Test Set 2 were among those listed in the ATcT Tables, the NIST WebBook, Cox and Pilcher’s Thermochemistry of Organic and Organometallic Compounds , or Pedley et al’s Thermochemical Data of Organic Compounds and/or from references in the literature. − A detailed list of literature references for reference/experimental Δ f H ° g,298 values selected for use in the training set and the two test sets is provided in Table S1.…”

Group Contribution Revisited: The Enthalpy of Formation of Organic Compounds with “Chemical Accuracy” Part IV

“…In Table 1, we have collected experimental data on cyclic molecules, preferably and many from reliable sources of experimental data. These include data on the cycloalkanes, alkylcyclopentanes and alkylcyclohexanes [31][32][33][34][35][36]. The complete set of literature references to all species considered is given in the Supplementary Material, Table S3.…”

Thermal Effects in Magnesium and Calcium Oxides

“…Five calorimetric experiments wrere completed for each compound, using the procedure previously described. 9 The amount of reaction in each experiment was determined from the mass of carbon dioxide produced in the combustion, which was near 2.75 g. in each experiment and measured to 0.1 mg. No evidence…”