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- Fiskari, Juha, 1967-, et al.
(författare)
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Quick non-destructive analysis of condensed lignin by ftir. part 2. pulp samples from acid sulfite cooking
- 2021
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 55:3-4, s. 263-270
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Tidskriftsartikel (refereegranskat)abstract
- In our previous work, we demonstrated how lignin condensation and precipitation taking place in kraft pulping can be detected and even quantified by Fourier Transform Infrared (FTIR) spectroscopy. Because lignin reactions in acid sulfite pulping are very different from those occurring during kraft cooking, a new analysis method is proposed to rapidly analyze the condensed lignin in acid sulfite pulp. This kind of analysis is useful for sulfite pulp mills to detect the elevated risk of black cook. This paper presents and discusses the novel method using FTIR spectroscopy to rapidly analyze lignin condensation in softwood pulp samples from acid sulfite processes. Several softwood pulp samples from acid sulfite pulping at varying levels of condensation were included in this research. According to the results, FTIR spectroscopy allows indirect quantification of lignin condensation in a difficult matrix of wood constituents, such as in incompletely delignified acid sulfite pulp.
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| 2. |
- Forsberg, Diana Carolina Reyes, et al.
(författare)
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On the importance of variation of alkalisation conditions on cellulose ether synthesis
- 2022
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Ingår i: Cellulose Chemistry and Technology. - : Publishing House of the Romanian Academy. - 0576-9787. ; 56:3-4, s. 227-238
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Tidskriftsartikel (refereegranskat)abstract
- With a multivariate approach, we investigate and correlate the effect of mercerization conditions on the properties of a cellulose ether. We have chosen to work with carboxymethylcellulose (CMC) for analytical reasons. As expected, the DS was found to increase when the NaOH/AGU (anhydroglucose unit) stoichiometric ratio (r) was increased (range 1.0–1.3) and [NaOH] was decreased (range 50-30%). However, such changes also favoured the formation of unwanted side products. Decreased (r) and increased [NaOH] resulted in increased heterogeneity, and thus the quantities of insoluble particles and unreacted chemicals also increased. As another result, the prediction between mercerisation and synthesis weakens. Consequently, a DS of 0.18–0.7 was obtained; the measured solubility was much lower than expected. A non-statistical distribution of substituents was further found. Interestingly, the relative importance of substitution at increases with an increased [NaOH].
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