Group Additive Values for the Gas‐Phase Standard Enthalpy of Formation, Entropy and Heat Capacity of Oxygenates

Abstract

A complete and consistent set of 60 Benson group additive values (GAVs) for oxygenate molecules and 97 GAVs for oxygenate radicals is provided, which allow to describe their standard enthalpies of formation, entropies and heat capacities. Approximately half of the GAVs for oxygenate molecules and the majority of the GAVs for oxygenate radicals have not been reported before. The values are derived from an extensive and accurate database of thermochemical data obtained by ab initio calculations at the CBS-QB3 level of theory for 202 molecules and 248 radicals. These compounds include saturated and unsaturated, α- and β-branched, mono- and bifunctional oxygenates. Internal rotations were accounted for by using one-dimensional hindered rotor corrections. The accuracy of the database was further improved by adding bond additive corrections to the CBS-QB3 standard enthalpies of formation. Furthermore, 14 corrections for non-nearest-neighbor interactions (NNI) were introduced for molecules and 12 for radicals. The validity of the constructed group additive model was established by comparing the predicted values with both ab initio calculated values and experimental data for oxygenates and oxygenate radicals. The group additive method predicts standard enthalpies of formation, entropies, and heat capacities with chemical accuracy, respectively, within 4 kJ mol(-1) and 4 J mol(-1) K(-1) for both ab initio calculated and experimental values. As an alternative, the hydrogen bond increment (HBI) method developed by Lay et al. (T. H. Lay, J. W. Bozzelli, A. M. Dean, E. R. Ritter, J. Phys. Chem.- 1995, 99, 14514) was used to introduce 77 new HBI structures and to calculate their thermodynamic parameters (Δ(f)H°, S°, C(p)°). The GAVs reported in this work can be reliably used for the prediction of thermochemical data for large oxygenate compounds, combining rapid prediction with wide-ranging application.

First‐principles based group additivity values for thermochemical properties of substituted aromatic compounds

“…[22][23][24][25] This accuracy is comparable to that of high level ab initio methods, which require substantially more time and effort. Benson's method has been successfully applied to standard enthalpies of formation of gas phase molecules, 4,15,17,22,24,25 and also to entropies and heat capacities. [13][14][15][16][23][24][25] To ensure that the values obtained via GA are reliable, the GAV and NNI definitions have to be internally consistent.…”

“…Benson's method has been successfully applied to standard enthalpies of formation of gas phase molecules, 4,15,17,22,24,25 and also to entropies and heat capacities. [13][14][15][16][23][24][25] To ensure that the values obtained via GA are reliable, the GAV and NNI definitions have to be internally consistent. This means that (1) the GAV parameters are assigned in a systematic way resolving all linear dependencies, 14 (2) the set of NNIs are comprehensive and well defined, and (3) all parameters are determined from reference data of equal quality.…”

“…This means that (1) the GAV parameters are assigned in a systematic way resolving all linear dependencies, 14 (2) the set of NNIs are comprehensive and well defined, and (3) all parameters are determined from reference data of equal quality. Reyniers and coworkers [22][23][24][25] have started to create such an internally consistent GAV/NNI database based on ab initio results at the CBS-QB3 level of theory. Currently this database contains GAV and NNI definitions that allow calculation of thermodynamic properties for aliphatic hydrocarbons like alkanes, alkenes, alkynes, and few cyclic hydrocarbons and their corresponding radicals, 22,23 oxygenates such as alcohols, esters, ethers, ketones, carboxylic acids, ketenes and their corresponding radicals, 25 and organic sulfur compounds.…”

“…[21][22][23][24][25][26][27][28] It has been shown that GA methods are able to calculate standard enthalpies of formation with "chemical accuracy," meaning with a standard deviation of not more than 4 kJ mol 21 . [22][23][24][25] This accuracy is comparable to that of high level ab initio methods, which require substantially more time and effort. Benson's method has been successfully applied to standard enthalpies of formation of gas phase molecules, 4,15,17,22,24,25 and also to entropies and heat capacities.…”

Understanding the reactivity of unsaturated alcohols: Experimental and kinetic modeling study of the pyrolysis and oxidation of 3-methyl-2-butenol and 3-methyl-3-butenol

“…Thermochemical data for molecules and radicals are taken from databases when possible [44][45][46][47], otherwise the thermodynamic functions are estimated using Benson's group additivity concept for thermochemistry [48], using recently proposed group additive values and hydrogen bond increments [41,45,46].…”