Structure of Lignosulphonates from Acidic Magnesium-Based Sulphite Pulping of<i>Eucalyptus globulus</i>

Marques, A.; Evtuguin, Dmitry V.; Magina, Sandra; Amado, Francisco; Prates, António

doi:10.1080/02773810903207762

Cited by 56 publications

(52 citation statements)

References 13 publications

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“…A similar observation was made previously based on NMR studies of eucalypt LS isolated from SSL (Marques et al 2009b). …”

Section: Wet Chemistry Analysessupporting

confidence: 84%

“…About 40% of SSL dry matter was removed during SSL dialysis. Marques et al (2009b) found that besides sugars and inorganics, the highly sulphonated monomeric/dimeric structures are removed during dialysis with this membrane and retentate becomes enriched in oligomeric LS. The Mw of purified LS was 2350 Da, which is almost triple of that of purified lignin isolated from kraft black liquor (Pinto et al 2003a).…”

Section: Molecular Weight Of Residual Lignin (L R )mentioning

confidence: 96%

“…The assignments of signals in 13 C NMR spectra are based on the analysis of proton-carbon correlation (HSQC) 2D NMR spectra of corresponding lignins (Figures 4 and 5). Moreover, the published database of sulphonated eucalypt lignins (Luthaes et al 2008;Marques et al 2009b) and native eucalypt lignins (Evtuguin et al 2001) served for interpretation. The assignments were additionally confirmed by the single-bond proton-proton correlation spectra (COSY, spectra are not shown) and HSQC spectrum of non-acetylated L R (Figure 6).…”

Section: Analyses By Nmrmentioning

confidence: 99%

“…The calculations have been carried out per one aromatic ring according to previously established methodology (Evtuguin et al 2001;Marques et al 2009b). The aromatic region equivalent to six carbon atoms was integrated at 103-156 ppm.…”

Section: Analyses By Nmrmentioning

confidence: 99%

“…Pulp was additionally washed with distilled water (1:100) and air-dried. Thin SSL was purified to obtain the lignosulphonate-rich fraction (L SSL sample) by dialysis with a membrane of 5000 nominal molecular weight cut-off (NMWCO) (Pierron) against distilled water for 8 h followed by freeze-drying of dialysate (Marques et al 2009b). The RL from pulp (L R sample) was isolated by soft acidolytic treatment (Evtuguin et al 2001), which was adopted from Pinto et al (2003a,b).…”

Section: Methodsmentioning

confidence: 99%

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Study on the residual lignin in Eucalyptus globulus sulphite pulp

2014

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Abstract:The residual lignin (L R sample) was isolated from unbleached acid sulphite pulp from Eucalyptus globulus with kappa number 18.2 by acidolysis and structurally characterized by wet chemistry and NMR techniques. The main structural features of L R were compared with lignin isolated from sulphite spent liquor (L SSL sample) and dioxane lignin (DL sample) from eucalypt wood. L R contains less sulphonic groups (4.4%) compared to L SSL (11.3%), and its molecular weight (2200 Da) is very close to that of DL (2600 Da). A part of sulphonic groups is located at the benzylic carbon in β-O-4′ and β-5′ structures. L R revealed ca. 20% lower abundance of β-O-4′ structures than DL, but ca. 40% higher abundance of these structures than L SSL . The degree of condensation of L R was higher than that of DL but lower than that of L SSL . The condensed structures in L R mainly originate from C6-linked syringyl units. The structural peculiarities of L R consisted of the relatively high proportion of syringyl units compared to DL and the strong structural association with hemicelluloses via benzyl ether linkages. The differences in the structure of residual lignins from eucalypt sulphite and kraft pulps have been discussed.

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“…A similar observation was made previously based on NMR studies of eucalypt LS isolated from SSL (Marques et al 2009b). …”

Section: Wet Chemistry Analysessupporting

confidence: 84%

Section: Molecular Weight Of Residual Lignin (L R )mentioning

confidence: 96%

Section: Analyses By Nmrmentioning

confidence: 99%

Section: Analyses By Nmrmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Study on the residual lignin in Eucalyptus globulus sulphite pulp

2014

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Sulphite Pulping

Evtuguin¹

2016

Lignocellulosic Fibers and Wood Handbook

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Combination of Reaction and Separation in Heterogeneous Catalytic Hydrogenation of Ethylformate

et al. 2015

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Continuous hydrogenation reaction of ethyl benzoylformate was studied over a (–)‐cinchonidine (CD)‐modified Pt/Al2O3 catalyst. The catalyst showed a good stability, and high enantioselectivity was achieved in the fixed‐bed reactor. Chromatographic separation of (R)‐ and (S)‐ethyl mandelate originating from a post‐continuous hydrogenation reaction of ethyl benzoylformate over the (–)‐CD‐modified Pt/Al2O3 catalyst was investigated in the same reaction mixture. A commercial column filled with a chiral selector resin was chosen as a perspective preparative‐scale adsorbent. Since adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post‐reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug‐flow model with linear driving force approximation.

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Structure of Lignosulphonates from Acidic Magnesium-Based Sulphite Pulping ofEucalyptus globulus

Cited by 56 publications

References 13 publications

Study on the residual lignin in Eucalyptus globulus sulphite pulp

Study on the residual lignin in Eucalyptus globulus sulphite pulp

Sulphite Pulping

Combination of Reaction and Separation in Heterogeneous Catalytic Hydrogenation of Ethylformate

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