Estimation of Total Aromatics and Their Distribution as Mono and Global Di-Plus Aromatics in Diesel-Range Products by NMR Spectroscopy

In the present work, a new method based on 1 H NMR spectroscopy has been developed for the estimation of total aromatics and their distribution as mono- and polynuclear (di-ring plus) aromatics in diesel-range fuel products. Multipulse NMR techniques such as, distortionless enhancement by polarization transfer and 2-dimensional heteronuclear correlation have been applied for the unambiguous assignment of the 2.0-3.5 ppm region due to α-substituents on the aromatic ring in the 1 H NMR spectra. The estimation of polynuclear aromatics is based on the estimation of bridgehead aromatic (Ar b ) and substituted aromatic (Ar q ) carbons using equations developed. The proposed 1 H NMR-based method correlates very well with the standard IP-391/ 90- and mass-spectrometric-based method (R 2 = 0.99).