Determination of phenolic hydroxyl groups in lignin by combined use of 1H NMR and UV spectroscopy

Eija Tiainen, Torbjörn Drakenberg, Tarja Tamminen, Kirsi Kataja, Anneli Hase

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)

Abstract

Two independent spectroscopic methods are presented and compared for the quantitation of the phenolic hydroxyl groups in lignins. The combined information is used to further elucidate the character of the lignin samples examined. The UV method is based on the difference of the spectroscopic properties of the ionised and the nonionised phenol. The method using 1H NMR spectroscopy is based on the exchange of phenolic protons in D2O. The difference in integrated proton intensities in the sample dissolved in DMSO and the sample with additional 20% D2O is proportional to the phenolic protons. The method based on UV spectroscopy uses differences in the maxima close to 300 nm and 350 nm of the sample dissolved in alkali and the neutral sample. The results using the two independent methods are in agreement for milled wood lignin, for kraft lignin and for model compounds carrying one aromatic hydroxyl group. For modified lignins and for model compounds with more than one aromatic hydroxyl group, the UV method gives too low values for phenolic hydroxyl groups. The combined results obtained by the two methods however provide information of the total amount of the phenolic groups and of the nature of the phenolic structure formed by the lignin refining.
Original languageEnglish
Pages (from-to)529-533
Number of pages5
JournalHolzforschung
Volume53
Issue number5
DOIs
Publication statusPublished - 1999
MoE publication typeA1 Journal article-refereed

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Lignin
Ultraviolet spectroscopy
Hydroxyl Radical
Nuclear magnetic resonance spectroscopy
Protons
Alkalies
Dimethyl Sulfoxide
Phenol
Refining
Wood
Phenols
Ion exchange

Cite this

Tiainen, Eija ; Drakenberg, Torbjörn ; Tamminen, Tarja ; Kataja, Kirsi ; Hase, Anneli. / Determination of phenolic hydroxyl groups in lignin by combined use of 1H NMR and UV spectroscopy. In: Holzforschung. 1999 ; Vol. 53, No. 5. pp. 529-533.
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abstract = "Two independent spectroscopic methods are presented and compared for the quantitation of the phenolic hydroxyl groups in lignins. The combined information is used to further elucidate the character of the lignin samples examined. The UV method is based on the difference of the spectroscopic properties of the ionised and the nonionised phenol. The method using 1H NMR spectroscopy is based on the exchange of phenolic protons in D2O. The difference in integrated proton intensities in the sample dissolved in DMSO and the sample with additional 20{\%} D2O is proportional to the phenolic protons. The method based on UV spectroscopy uses differences in the maxima close to 300 nm and 350 nm of the sample dissolved in alkali and the neutral sample. The results using the two independent methods are in agreement for milled wood lignin, for kraft lignin and for model compounds carrying one aromatic hydroxyl group. For modified lignins and for model compounds with more than one aromatic hydroxyl group, the UV method gives too low values for phenolic hydroxyl groups. The combined results obtained by the two methods however provide information of the total amount of the phenolic groups and of the nature of the phenolic structure formed by the lignin refining.",
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Determination of phenolic hydroxyl groups in lignin by combined use of 1H NMR and UV spectroscopy. / Tiainen, Eija; Drakenberg, Torbjörn; Tamminen, Tarja; Kataja, Kirsi; Hase, Anneli.

In: Holzforschung, Vol. 53, No. 5, 1999, p. 529-533.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Determination of phenolic hydroxyl groups in lignin by combined use of 1H NMR and UV spectroscopy

AU - Tiainen, Eija

AU - Drakenberg, Torbjörn

AU - Tamminen, Tarja

AU - Kataja, Kirsi

AU - Hase, Anneli

PY - 1999

Y1 - 1999

N2 - Two independent spectroscopic methods are presented and compared for the quantitation of the phenolic hydroxyl groups in lignins. The combined information is used to further elucidate the character of the lignin samples examined. The UV method is based on the difference of the spectroscopic properties of the ionised and the nonionised phenol. The method using 1H NMR spectroscopy is based on the exchange of phenolic protons in D2O. The difference in integrated proton intensities in the sample dissolved in DMSO and the sample with additional 20% D2O is proportional to the phenolic protons. The method based on UV spectroscopy uses differences in the maxima close to 300 nm and 350 nm of the sample dissolved in alkali and the neutral sample. The results using the two independent methods are in agreement for milled wood lignin, for kraft lignin and for model compounds carrying one aromatic hydroxyl group. For modified lignins and for model compounds with more than one aromatic hydroxyl group, the UV method gives too low values for phenolic hydroxyl groups. The combined results obtained by the two methods however provide information of the total amount of the phenolic groups and of the nature of the phenolic structure formed by the lignin refining.

AB - Two independent spectroscopic methods are presented and compared for the quantitation of the phenolic hydroxyl groups in lignins. The combined information is used to further elucidate the character of the lignin samples examined. The UV method is based on the difference of the spectroscopic properties of the ionised and the nonionised phenol. The method using 1H NMR spectroscopy is based on the exchange of phenolic protons in D2O. The difference in integrated proton intensities in the sample dissolved in DMSO and the sample with additional 20% D2O is proportional to the phenolic protons. The method based on UV spectroscopy uses differences in the maxima close to 300 nm and 350 nm of the sample dissolved in alkali and the neutral sample. The results using the two independent methods are in agreement for milled wood lignin, for kraft lignin and for model compounds carrying one aromatic hydroxyl group. For modified lignins and for model compounds with more than one aromatic hydroxyl group, the UV method gives too low values for phenolic hydroxyl groups. The combined results obtained by the two methods however provide information of the total amount of the phenolic groups and of the nature of the phenolic structure formed by the lignin refining.

U2 - 10.1515/HF.1999.087

DO - 10.1515/HF.1999.087

M3 - Article

VL - 53

SP - 529

EP - 533

JO - Holzforschung

JF - Holzforschung

SN - 0018-3830

IS - 5

ER -