Sample age effect on parameters of dynamic nuclear polarization in certain difluorobenzen isomers/MC800 asphaltene suspensions

Abstract

Abstract Because of magnetic spin–spin interactivity between 19F nucleus of the solvent and delocalized electrons on the MC800 asphaltene, the Overhauser dynamic nuclear polarization (DNP) method is able to give a substantial boost in the signal acquired from studies focused on nuclear magnetic resonance (NMR). The suspensions of asphaltene in difluorobenzene isomers were studied using Overhauser effect type DNP and NMR investigations at room temperature in a small magnetic field of 1.53 mT. The used asphaltene was obtained from MC800 liquid asphalt from Heavy Iran. Each sample of the solvent medium was produced at three different concentrations of asphaltene. These samples were stored in the refrigerator for 7 years, until DNP parameters were found by new DNP tests. As a result, the influence of sample age on parameters of DNP was studied, and then the findings were analyzed.