Kraft Odor

Sarkanen, K. V.; Hrutfiord, Bjorn F.; Johanson, L. N.; Gardner, Howard

doi:10.2524/jtappij.26.9_434

Cited by 21 publications

(28 citation statements)

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“…In fact, the cleavage of these linkages leads to the appearance of phenolic hydroxyl groups in the aryl substituent removed from the b position. 24,25 The same trend was observed by Gilarranz et al 23 when studying lignin behavior during the autocatalyzed methanol pulping of Eucalyptus globulus.…”

Section: Phenolic Hydroxyl Contentsupporting

confidence: 63%

Structural modification and characterization of lignosulfonate by a reaction in an alkaline medium for its incorporation into phenolic resins

Mansouri

Farriol

Salvadó

2006

J of Applied Polymer Sci

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ABSTRACT:We studied the enhancement of lignin reactivity in an alkaline medium, using sodium hydroxide in a microreactor set. The chemical composition and structural characterization of the reacted lignosulfonate in terms of the phenolic hydroxyl groups, aromatic protons, weight-average molecular weight, number-average molecular weight, and lignosulfonate content of all reacted lignins were determined. The techniques that we used were ultraviolet spectroscopy, proton nuclear magnetic resonance spectroscopy, and aqueous gel permeation chromatography. Using response surface methodology, we studied how the temperature and reaction time affected the lignin properties. The reaction conditions were temperatures between 116 and 1808C and reaction times between 18 and 103 min. Modeled response surfaces showed that the two factors affected the lignin properties within the studied ranges. The phenolic hydroxyl groups, aromatic protons, and lignosulfonate content increased when the severity of the treatment increased. The weight-average molecular weight, number-average molecular weight, and solid yield (%) decreased when the severity of the treatment increased. The reactivity of the modified lignins was studied with a formaldehyde reactivity test: more severe conditions produced greater improvements in the formaldehyde reactivity.

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Section: Phenolic Hydroxyl Contentsupporting

confidence: 63%

Structural modification and characterization of lignosulfonate by a reaction in an alkaline medium for its incorporation into phenolic resins

Mansouri

Farriol

Salvadó

2006

J of Applied Polymer Sci

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“…The absorption bands can be assigned empirically to structural groups, based on a multitude of results obtained both from model compounds and lignins. 4,6,20,21 The assignment is given in Figure 1 and Table III. The spectrum of kenaf fiber MWL shows hydrogen bonded OAH stretching absorption around 3400 cm À1 and a prominent CAH stretching absorption around 2900 cm À1 . In the fingerprint region, between 1800 and 900 cm À1 , many sharp and discrete absorption bands because of various functional groups present in kenaf fiber MWL constituents are observed.…”

Section: Ftir Spectroscopymentioning

confidence: 99%

The isolation and characterization of lignin of kenaf fiber

Yan

2009

J of Applied Polymer Sci

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In this article, milled wood lignin (MWL) was isolated and purified from retted kenaf fiber, the lignin obtained was characterized by elemental analysis, FTIR, 1 H-NMR, and 13 C-NMR spectroscopy. The C 9 formula is calculated for kenaf fiber MWL as C 9 H 9.32 O 3.69 (OCH 3 ) 1.30 . The spectra of FTIR, 1 H-NMR, and 13 C-NMR show the kenaf fiber lignin to be of the G/S type with high proportion of syringyl (S) unit. The numbers of phenolic and aliphatic hydroxyl groups in the kenaf fiber MWL are estimated to be 0.14 and 1.31, respectively, per C 9 unit. The OH aliph is 90.3% in total numbers of hydroxyl groups of kenaf fiber MWL, and the OH ph is 9.7%. It is evident that the b-O-4 structures are mainly linkage in the MWL of kenaf fiber, which contain more erythro stereochemistry type in b-O-4 units than thero stereochemistry type. In general, the characteristics of lignin of kenaf fiber are similar to that of hardwood.

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“…Band assignments presented in this work are based on prior literature reports for IR and Raman spectra of lignin and holocellulose (13,14,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). Lignin content was calculated by ratioing the area of the 1600 cm 01 band associated with the aromatic stretch of the phenyl groups of lignin to the cellulose band structure between 1200 and 1010 cm 01 .…”

Section: Resultsmentioning

confidence: 99%