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 IH NMR spectroscopy has bee n developed for the estimation of total aromatics and their distributi on as mono- and polynuclear (di-ring plus) aromatics in diesel-range f uel products. Multipulse NMR techniques such as, distortionless enhanc ement by polarization transfer and 2-dimensional heteronuclear correla tion have been applied for the unambiguous assignment of the 2.0-3.5 p pm region due to alpha-substituents on the aromatic ring in the H-1 NM R spectra. The estimation of polynuclear aromatics is based on the est imation of bridgehead aromatic (Ar-b) and substituted aromatic (Ar-q) carbons using equations developed. The proposed H-1 NMR-based method c orrelates very well with the standard IF-391/90- and mass-spectrometri c-based method (R-2 = 0.99).