Prediction of the enthalpy of combustion of organic compounds

Abstract

In many instances, particularly when preparing plant designs, the enthalpy of combustion of compounds must be estimated. We present in this note a simple and accurate method to obtain such enthalpies at 298.15 K. Basically, we develop correction factors for a wide variety of functional groups and branching modes to correct simple relationships for alkane combustion. The method has been shown to apply to gaseous, liquid, and solid compounds with errors less than 1%. In addition, the enthalpy of combustion can be converted to a standard enthalpy of formation; as such, the method compares favorably to the best estimation techniques now available for the property. Enthalpy of CombustionIt is well known that for most homologous series, there is a first-order correspondence between the total number of carbon atoms and the enthalpy of combustion (Handrick, 1956). We have utilized this concept to estimate enthalpies of combustion by developing correction factors to determine an equivalent alkane chain length, N , such that, with this parameter, one can then utilize simple relations developed for n-alkanes. Thus we define N asHere C is the total number of carbon atoms in the molecule, while AN, values are correction factors for functional groups and chain branching. Values of ANi vary depending upon whether the compound is a gas (g), liquid (I), or solid (s). In Table 1 we show values of AN, applicable to many compound types. In cases where there may be an ambiguity, clarifying remarks are given with the table. It can be seen that a wide variety of organic compounds may be treated, including aliphatic, naphthenic, and aromatic materials.With values of AN, for the compound of interest, N can be found from Eq. 1 and the enthalpy of combustion AHzfrom Eqs. 2 through 4. Here AH: is defined as the difference between the enthalpy of a compound and that of its products of combustion in the gaseous state, all a t the standard state of 298.1 5 K and 10' Pa (1 bar). The products of combustion are H,O(g), C 0 2 , SO2, N,, and HX(g) with X = halogen. AHXg) = -198.42-615.14 N (kJ/mol) (2) AH:(l) = -196.98-610.13 N (kJ/mol) (3) AH:(s) = -206.21-606.56 N (kJ/mol)In Appendix I we illustrate the applicability of the method to a number of compound types, both simple and quite complex. (A more detailed statistical comparison between calculated and literature values of AH: is available upon request from the author.)The method was applied to a large number of compounds for which the equivalent alkane chain length N ranged from 1 to 66. Further limitations were an upper limit equal to one for the ratio between the number of corrections and the number of carbon atoms and, for halides, an upper limit equal to one for the ratio between halogen and hydrogen atoms. These limitations were fixed because it was noted that beyond the indicated limits the application of the method yielded low estimates. This is illustrated by the following results for chlorinated gaseous ethanes, using calculated and literature values as indicated. AH: calc.

A Comprehensive Methodology for Development, Parameter Estimation, and Uncertainty Analysis of Group Contribution Based Property Models—An Application to the Heat of Combustion

“…We There are a number of GC-based methods for the estimation of in the literature. Cardozo 22 estimated enthalpies of combustion by developing correction factors from an equivalent alkane chain length and then utilized these factors along with simple relations developed for n-alkanes. al.…”

Prediction of the net heat of combustion of organic compounds based on atom-type electrotopological state indices

“…These combustion products are CO 2 (g), F 2 (g), Cl 2 (g), Br 2 (g), SO 2 (g), N 2 (g) and H 2 O (g) (DIPPR, 2006 (Hshieh, 1999). Thus, the DH c o values of chemicals must be available when preparing plant designs (Cardozo, 1986 As well known, it is a basic law that the property of a compound is dependent on its structure. Quantitative structure-property relationship (QSPR) study which is based on the law above has been widely applied for prediction in various subjects by the researchers all over the world.…”

“…The DH c o property of compounds has already been studied by a few researchers such as Cardozo (1986), Gharagheizi (2008), Hshieh, Hirsch, and Beeson (2003), and Seaton and Harrison (1990), and several models have been built. However, these reported models are all based on linear combinations of the molecular descriptors.…”

A new method for predicting the heats of combustion of polynitro arene, polynitro heteroarene, acyclic and cyclic nitramine, nitrate ester and nitroaliphatic compounds

“…A simple prediction model has been developed by Cardozo [11] to relate the length of chain and heat of combustion based on 1168 organic compounds. Cardozo's method [11] cannot be applied for polynitroheteroarenes, acyclic and cyclic nitramines as well as energetic compounds with nitrate functional groups because group correction factors have not been specified for the compounds containing N-NO 2 and O-NO 2 functional groups and molecular fragments in polynitroheteroarenes. Seaton and Harrison [10] have assumed some combustion products for compounds or mixtures of compounds composed of any of 71 elements to estimate the heats of combustion.…”