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

Abstract

In the present work, a new method based on 1H 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 1H NMR spectra. The estimation of polynuclear aromatics is based on the estimation of bridgehead aromatic (Arb) and substituted aromatic (Arq) carbons using equations developed. The proposed 1H NMR-based method correlates very well with the standard IP-391/90- and mass-spectrometric-based method (R2 = 0.99).