Abstract
The capillary gas-liquid chromatographic methods and/or gas chromatographic-mass spectrographic methods had been tested to determine the monomethylparaffins in n-paraffin fractions separated from petroleum distillates by means of urea. 27 monomethylparaffins, included all isomers of monomethyldecane, monomethylundecane and monomethyldodecane, were identified or estimated in n-paraffin fraction separated from middle distillates, and these monomethylparaffins amounted to 95wt% of all components other than n-paraffins. In the C18 fraction of n-paraffins separated from heavy distillates, all isomers of monomethylheptadecane were detected and in the C20 fraction all isomers of monomethylnonadecane were also detected. From these results it was estimated that all sorts of isomers of monomethylparaffins were present in n-paraffin fractions separated from petroleum fractions by means of urea and the amount of those monomethylparaffins occupied a large portion of components other than n-paraffins all over the boiling range.
