Alkaline pulping with additives. A review

Kubes, G. J.; Fleming, B. I.; Macleod, J. M.; Bolker, H. I.

doi:10.1007/bf00350570

Cited by 24 publications

(14 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to the severity factors shown in Table , temperature significantly influenced them, being about 40–50% higher at 170 °C. The addition of AQ is not included in this estimate; however, AQ can be considered as an intensifier of severity since it forms a redox system with carbohydrates and lignin, promoting the cleavage of β– O –4 linkages in lignin. , …”

Section: Resultsmentioning

confidence: 99%

“…The addition of AQ is not included in this estimate; however, AQ can be considered as an intensifier of severity since it forms a redox system with carbohydrates and lignin, promoting the cleavage of β−O−4 linkages in lignin. 17,18 Elemental Analysis. Table 2 depicts the elemental composition (C, H, and O), methoxyl content, and C9formulas for each lignin.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Alkaline Pretreatment Severity Leads to Different Lignin Applications in Sugar Cane Biorefineries

Menezes

Rencoret

Nakanishi

et al. 2017

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

Lignin, a multifunctional major biomass component, has a prominent potential as feedstock to be converted into high value-added products. Lignin is available in high amounts as side streams during cellulosic ethanol production, and within the biorefinery context, it is important to assess its structural characteristics in order to explore its potential to replace some petroleum-based reactants. In this study, some important features were evaluated for different lignins such as lignin purity and the amounts of syringyl (S), guaiacyl (G), and p-hydroxyphenyl (H) units. Four alkaline lignins, generated from a pilot-scale pretreatment of sugar cane bagasse (NaOH 1.5%, 30 min), were evaluated according to the severity of the alkaline pretreatment (130 or 170 °C, with or without the addition of anthraquinone). The different pretreatments produced lignins with different chemical characteristics that can be used for different purposes in sugar cane biorefineries. As the severity of alkaline pretreatment increased, the recovered lignins presented higher amounts of H-and lower amounts of S-lignin units. In particular, the lignin obtained at 170 °C with the addition of anthraquinone presented the highest content of H-and the lowest content of S-lignin units, which would present higher reactivity toward formaldehyde in phenolic resins.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Alkaline Pretreatment Severity Leads to Different Lignin Applications in Sugar Cane Biorefineries

Menezes

Rencoret

Nakanishi

et al. 2017

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…It is well-known that the overall delignification rate in an alkaline medium is strongly related to the liquor reducing potential. Cellulose and hemicelluloses chains have reducing end groups (anomeric carbons), which are sources of reducing potential in alkaline liquor . In addition, the oxidation of anomeric carbon from aldehyde to carboxyl prevents the endwise depolymerization of cellulose and hemicelluloses chains .…”

Section: Results and Discussionmentioning

confidence: 99%

“…In addition, the oxidation of anomeric carbon from aldehyde to carboxyl prevents the endwise depolymerization of cellulose and hemicelluloses chains . Using a redox catalyst as a transferring electrons source can ensure the reduction of lignin by oxidation of anomeric carbons of reducing end groups of cellulose and hemicelluloses chains . This increases the delignification rate preventing both lignin recombination and depolymerization of cellulose and hemicelluloses …”

Section: Results and Discussionmentioning

confidence: 99%

“…To overcome this peeling effect, the technological solution adopted by the pulp and paper industry has been the use of a redox catalyst. To this end, anthraquinone (0.1–0.5%, w w –1 ) is widely used as a redox catalyst to promote oxidation and reduction cycles during soda (NaOH) delignification of LB. − The redox catalyst promotes oxidation of aldehyde end groups of the polysaccharide chains to aldonic acid and subsequent reduction of lignin. This leads to polysaccharide preservation and also to lignin degradation with a reduced number of condensation reactions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

2-Hydroxy-1,4-naphthoquinone (Lawsone) as a Redox Catalyst for the Improvement of the Alkaline Pretreatment of Sugarcane Bagasse

et al. 2020

View full text Add to dashboard Cite

This study evaluated the use of a new redox catalyst (2-hydroxy-1,4-naphthoquinone, HNQ) in order to contribute to the preservation of the carbohydrate fraction and to increase delignification of sugarcane bagasse (SB) subjected to soda pretreatment, without inhibiting enzyme activity during saccharification. The effects of HNQ were compared to the well-known redox catalyst anthraquinone (AQ). A 25‑1 fractional design and a 22 central composite design were used for optimization of the soda-HNQ pretreatment of SB. The use of HNQ promoted preservation of 76.4% cellulose and 86.2% hemicelluloses, as well as 86.1% delignification of raw SB, showing a superior performance than AQ. The optimized pretreatment conditions were 150 °C, 60 min, 15% (w w–1) NaOH, 0.4% (w w–1) HNQ, and a liquid-to-solid ratio of 9.6 mL g–1. Saccharification of SB pretreated by soda-HNQ yielded higher overall glucose (74.0%) and xylose (74.3%) yields compared to SB pretreated by AQ (64.9% glucose, 67.3% xylose).

show abstract