New semiempirical relationship for evaluation of aromaticity of crude oil and petroleum products from 1H NMR spectra

A new method was proposed for the evaluation of aromaticity (the percentage of aromatic C atoms in crude oil and petroleum products) based on 1H NMR spectra. © 2014 Springer Science+Business Media New York

New semiempirical relationship for evaluation of aromaticity of crude oil and petroleum products from 1H NMR spectra

A new method was proposed for the evaluation of aromaticity (the percentage of aromatic C atoms in crude oil and petroleum products) based on 1H NMR spectra. © 2014 Springer Science+Business Media New York

Spin-spin relaxation in the 17O NMR spectra of Na+ and K+ water clusters

Relaxation characteristics of Na+ and K+ water clusters were studied by 17O NMR spectroscopy. The influence of viscosity p and pH of solution was taken into account; for both electrolytes in the concentration range 10-5-4 M, spin-spin relaxation times are greater than those for pure water. For K+ clusters, maxima of the concentration dependence of 17O spin-spin relaxation time have been found

Quantitative analysis of multicomponent mixtures of petroleum products by a combination of NMR spectroscopy and mass spectrometry

A combination of mass spectrometry and nuclear magnetic resonance spectroscopy was used to monitor the process of manufacture of liquid fuels with a high density and a high specific calorific value from the by-products of pyrolysis of crude oil fractions. This methodology provided information that characterizes the component, fragment, and group composition of samples for all stages of this process and facilitated the development of ideas on the genetic relation of components of heavy oil residues. Copyright © 2005 by MAIK "Nauka/Interperiodlca" (Russia)

Spin-spin relaxation of aqueous clusters of Na+ and K+ as studied by O-17 NMR spectroscopy

The relaxation characteristics of the O-17 nucleus in aqueous clusters of Na+ and K+ were studied by nuclear magnetic resonance (NMR) spectroscopy. The influence of the viscosity p and pH value of the solution on the spin-spin relaxation of O-17 nucleus was investigated. In the presence of either electrolyte at concentrations from 10(5) to 4 mol/l, the spin-spin relaxation time is longer than for doubly distilled water. This suggests that the water network experiences rearrangement under the action of these cations

Spin-spin relaxation in the 17O NMR spectra of Na+ and K+ water clusters

Relaxation characteristics of Na+ and K+ water clusters were studied by 17O NMR spectroscopy. The influence of viscosity p and pH of solution was taken into account; for both electrolytes in the concentration range 10-5-4 M, spin-spin relaxation times are greater than those for pure water. For K+ clusters, maxima of the concentration dependence of 17O spin-spin relaxation time have been found

Spin-spin relaxation of aqueous clusters of Na+ and K+ as studied by O-17 NMR spectroscopy

The relaxation characteristics of the O-17 nucleus in aqueous clusters of Na+ and K+ were studied by nuclear magnetic resonance (NMR) spectroscopy. The influence of the viscosity p and pH value of the solution on the spin-spin relaxation of O-17 nucleus was investigated. In the presence of either electrolyte at concentrations from 10(5) to 4 mol/l, the spin-spin relaxation time is longer than for doubly distilled water. This suggests that the water network experiences rearrangement under the action of these cations

Quantitative analysis of multicomponent mixtures of petroleum products by a combination of NMR spectroscopy and mass spectrometry

A combination of mass spectrometry and nuclear magnetic resonance spectroscopy was used to monitor the process of manufacture of liquid fuels with a high density and a high specific calorific value from the by-products of pyrolysis of crude oil fractions. This methodology provided information that characterizes the component, fragment, and group composition of samples for all stages of this process and facilitated the development of ideas on the genetic relation of components of heavy oil residues. Copyright © 2005 by MAIK "Nauka/Interperiodlca" (Russia)