NMR spectroscopy of complex mixtures of petroleum organosulphur compounds

Kanitskaya, L. V.; Кушнарев, Д. Ф.; Rozhenko, Alexander; Bzhezovskii, V. M.; Mazitova, F. N.; Iglamova, N. A.; Калабин, Г. А.

doi:10.1016/0031-6458(89)90010-5

Cited by 2 publications

(7 citation statements)

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“…Earlier works on the studies of spruce MWL with quantitative 1 H and 13 C NMR ( − ) reported very high amounts of carbonyl and ester groups. However, these values are not consistent with data obtained by wet chemistry methods ( Table ) or any other reports related to 13 C NMR of spruce lignin.…”

Section: Resultsmentioning

confidence: 94%

“…In the aromatic region, signals of different moieties are partially overlapped. In addition, some calculated values are obtained after subtraction of experimental or theoretical values, which are more than 1 order of magnitude higher than the value obtained; often, calculations require assumptions or/and the use of literature data ( − ). Therefore, we consider these calculations as approximate.…”

Section: Resultsmentioning

confidence: 99%

“…For the quantitative 13 C NMR, the concentration of lignin was 20%; a 90° pulse width, a 1.4 s acquisition time, and a 1.7 s relaxation delay were used. Chromium(III) acetylacetonate (0.01 M) was added to the lignin solution to provide complete relaxation of all nuclei ( , ). A total of 20 000 scans were collected.…”

Section: Methodsmentioning

confidence: 99%

“…The development of quantitative 13 C NMR in lignin analysis () was an important milestone in lignin chemistry. However, despite the wide use of this technique for the characterization of lignin structure, there are few comprehensive works on lignin quantification with 13 C NMR ( − ). Quite often, 13 C NMR is used only for the estimation of some specific moieties ( − ).…”

Section: Introductionmentioning

confidence: 99%

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A Comprehensive Approach for Quantitative Lignin Characterization by NMR Spectroscopy

Capanema

Balakshin

Kadla

2004

J. Agric. Food Chem.

449

508

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A detailed approach for the quantification of different lignin structures in milled wood lignin (MWL) has been suggested using a combination of NMR techniques. 1H-13C heteronuclear multiple quantum coherence and quantitative 13C NMR of nonacetylated and acetylated spruce MWL have been found to have a synergetic effect, resulting in significant progress in the characterization of lignin moieties by NMR. About 80% of side chain moieties, such as different beta-O-4, dibenzodioxocin, phenylcoumaran, pinoresinol, and others, have been identified on the structural level. The presence of appreciable amounts of alpha-O-alkyl and gamma-O-alkyl ethers has been suggested. Although the quantification of various condensed moieties was less precise than for side chain structures, reliable information can be obtained. Comparison of the calculated results with known databases on spruce MWL structure shows that the suggested approach is rather informative and comparable with the information obtained from the combination of various wet chemistry methods. Discrepancies between the results obtained in this study and those previously published are discussed.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Comprehensive Approach for Quantitative Lignin Characterization by NMR Spectroscopy

Capanema

Balakshin

Kadla

2004

J. Agric. Food Chem.

449

508

View full text Add to dashboard Cite

show abstract

“…The number of scans was 20,000-100,000. Quantitative calculations involving 13 C NMR spectra were performed according to methods reported before [2][3][4] …”

Section: Methodsmentioning

confidence: 99%