Comparison of oxidation behavior of linear and branched alkanes

Abstract

In this research, the oxidation behavior of six linear and branched alkanes was investigated using high-pressure differential scanning calorimeter (HP-DSC) and thermogravimetry coupled with Fourier-transform infrared spectroscopy (TG-FTIR) to compare the similarities and differences between branched and linear alkanes. The results indicated that both branched and linear alkanes showed only low-temperature oxidation (LTO), which implies that alkanes barely contribute in coke formation and thus no obvious high-temperature oxidation (HTO) was observed as no enough fuel was deposited. The LTO of linear alkanes seems to be independent of their carbon number, which, however, does not apply to branched alkanes. The oxidation behavior of branched alkanes was different from their linear chain counterparts due to the effect of their different molecule structure. Branched alkanes reacted earlier and faster at initial stage relative to their linear chain counterparts, but their reaction rates became slower at later stage with the increase of temperature. Branched alkanes can produce some oxidized compounds with CO group, while linear alkanes can form more carbonyl groups and some oxidized compounds (like carboxylic acids) that can help to produce more CO2 by decomposition.