Structure of Maya Asphaltene−Resin Complexes through the Analysis of Soxhlet Extracted Fractions

Abstract

A sample of Maya asphaltene was subjected to a purification process using Soxhlet extraction techniques to obtain a series of maltene fractions. These fractions were analyzed in detail via field-desorption mass spectrometry (FDMS), electron impact mass spectrometry (EIMS), and Fourier transform infrared (FTIR) spectroscopy techniques. The results from these analyses indirectly confirmed the idea that the asphaltene−resin complexes present different strength forces. A more significant aromaticity and a higher content of heterocyclic compounds and ketones have also been found in the original asphaltene sample than those present in the maltene fractions. In addition, the determination of the molecular weight by EIMS of the maltenes outside and inside the micelles revealed that the latter fractions possessed longer alkyl side chains, which contribute to augment the asphaltene solubility.