Year-Dependent Change of DNP Parameters in p-Difluorobenzene Suspension with Asphaltene

Year 2021, Volume: 10 Issue: 2, 370 - 374, 07.06.2021

Handan Engin Kırımlı

https://doi.org/10.17798/bitlisfen.870594

Abstract

Petroleum asphaltenes are the heaviest, most aromatic and most coplex component of crude oil and asphaltenes are paramagnetic. Overhauser Dynamic nuclear polarization (ODNP) were performed to study samples of asphaltene/ p-Difluorobenzene at 1.53 mT. p-difluorobenzen solvent with asfalten in three different concentrations waiting five years with oxygen removed have been stuied. Dynamic nuclear polarization parameters were determined by performing ODNP experiments again. The results of our studies and the calculated parameters, especially the coupling parameter, indicates that there were dipolar interactions between nuclei and free electron spins. These dipolar interactions indicate that, at the end of five years the the asphaltene micelles in suspension agglomerated and that make the molecule movements slower. The obtained dynamic nuclear polarization parameters were compared with their values in the literature and it was observed that the parameters decreased slightly with time.

Keywords

DNP, Overhauser Effect, Asphaltene, Sample Age.

Year-Dependent Change of DNP Parameters in p-Difluorobenzene Suspension with Asphaltene

Abstract

Petrol asfaltenleri ham petrolün en ağır, en aromatik ve en kompleks bileşenidir ve asfaltenler paramanyetiktir. Overhauser Dinamik nükleer polarizasyon (ODNP), 1.53 mT'da asfalten / p-Diflorobenzen örneklerini incelemek için gerçekleştirildi. Oksijenden uzaklaştırılarak beş yıl bekletilen asfaltenli p-difluorobenzen çözgen üç farklı konsantrasyonda çalışıldı. ODNP deneyleri tekrar yapılarak, Dinamik nükleer polarizasyon parametreleri belirlendi. Çalışmalarımızın sonuçları ve hesaplanan parametreler, özellikle çiftlenme parametresi, çekirdek ve serbest elektron spinleri arasında dipolar etkileşmeler olduğunu göstermektedir. Bu dipolar etkileşmeler, beş yılın sonunda süspansiyondaki asfalten misellerinin topaklandığını ve molekül hareketlerini yavaşlattığını göstermektedir. Elde edilen dinamik nükleer polarizasyon parametreleri literatürdeki değerleri ile karşılaştırılmış ve parametrelerin zamanla bir miktar azaldığı görülmüştür.

Keywords

DNP, Overhauser Etkisi, Asfalten, Örnek Yaşı

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