A simple correlation for prediction of autoignition temperature of various classes of hydrocarbons

A new reliable simple model is presented for estimating the autoignition temperatures (AITs) of different classes of hydrocarbons including alkanes, alkenes, cycloalkanes, cycloalkenes, alkynes, and aromatics. For various categories of hydrocarbons with general formula \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{C}}_{{a_{1} }} {\text{H}}_{{a_{2} }} $$\end{document}, the new correlation can be expressed as:\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {\text{AIT}} = 647 + 33.33a_{1} - 20.79a_{2} + 58.20F_{\text{SH}} + 81.03F_{\text{BH}} $$\end{document}where two functions FSH and FBH are related to size and branches of different classes of hydrocarbons, respectively. The proposed simple model can predict the AIT of any complex hydrocarbons through the knowledge of their molecular structures. The novel correlation is derived and tested for a large number of hydrocarbons including 274-compound database, which is the largest dataset with respect to previous works. It is shown that the estimated results of the new method have a lower root mean square deviation of AIT as compared to three of the best available predictive methods.