The deacetylation reaction in Eucalyptus wood: Kinetics and effects on the effective diffusion

Inalbon, María Cristina; Mocchiutti, Paulina; Zanuttini, Miguel Angel Mario

doi:10.1016/j.biortech.2008.10.054

Cited by 13 publications

(28 citation statements)

References 9 publications

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“…The values are close to those published before for the same raw material (Inalbon et al 2009 ), when only alkali was present in the treatment liquor.…”

Section: Relationship Between Eccsa a And Reaction Degreesupporting

confidence: 90%

“…Deacetylation reaction The contents of acetyl groups after treatment under different conditions (Table 2) were determined and the kinetic expression for the deacetylation reaction rate (R Acetyl , % min -1 ) previously published (Inalbon et al 2009 ) was fi tted to data. Figure 2 Evolution of ECCSA A for radial (r) and tangential (t) slices treated with kraft liquor (sulphidity 25 % ).…”

Section: Relationship Between Eccsa a And Reaction Degreementioning

confidence: 99%

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Wood capillarity and deacetylation during eucalyptus alkaline impregnation. Sulphidity effects and comparison between transverse directions

et al. 2012

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The relative ion transport capacity of wood -the "effective capillary cross sectional area" (ECCSA) -is determined in this work, based on the analogy with the relation between the electrical conductivities of wood and liquid medium. Wood was treated under different conditions and then the corresponding ECCSA A (the index A is for alkali) is estimated from the value obtained in an inert solution at room temperature (ECCSA Inert ). The difference between radial and tangential ECCSA A values is constant irrespective of pH, time, temperature and the presence of sodium sulfi de in the treatment liquor. The results show that ECCSA A is dependent on the degree of removal of native acetyl groups from hardwood O-acetyl-glucuronoxylan. A kinetic expression for Eucalyptus wood deacetylation is validated and used to establish the relationship between the acetyl content and ECCSA A in both anatomical directions.

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“…The values are close to those published before for the same raw material (Inalbon et al 2009 ), when only alkali was present in the treatment liquor.…”

Section: Relationship Between Eccsa a And Reaction Degreesupporting

confidence: 90%

Section: Relationship Between Eccsa a And Reaction Degreementioning

confidence: 99%

Wood capillarity and deacetylation during eucalyptus alkaline impregnation. Sulphidity effects and comparison between transverse directions

et al. 2012

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“…The water retention ability of wood meal also increases with increasing degrees of deacetylation (Zanuttini et al 1998). Inalbon et al (2009) demonstrated that deacetylation contributes a lot to wood swelling. As the blocking of OH groups by acetyl groups via hydrogen bonds is eliminated, swelling restrictions are removed (Sumi et al 1964).…”

Section: Introductionmentioning

confidence: 99%

Improved impregnation efficiency and pulp yield of softwood kraft pulp by high effective alkali charge in the impregnation stage

Brännvall

Bäckström²

2016

Holzforschung

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Abstract:A pulp yield increase up to 2% can be achieved by impregnation with a liquor containing 2 M effective alkali (EA) concentration instead of 1 M. The yield increase is due to higher cellulose and glucomannan contents in the pulp, which can be rationalized by less yield loss by peeling, as impregnation is more effective at an elevated EA level. A rapid loading of chips with alkali can be realized due to a high diffusion rate. When the temperature becomes higher in the cooking stage, enough alkali is available for delignification reactions without the risk of alkali depletion in the chip core, so that the delignification is more homogeneous.

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“…Modeling could contribute a lot to this goal. In the context of kraft cooking liquor impregnation (KLI), reaction kinetic models exist for deacetylation (Inalbon et al 2009 ) and galactoglucomannan degradation (Paananen et al 2010 ). Both models take into account the effect of hydroxyl ion (OH -) molality and temperature, and Inalbon et al (2009) also considered the effect of ionic strength.…”

Section: Introductionmentioning

confidence: 99%

“…In the context of kraft cooking liquor impregnation (KLI), reaction kinetic models exist for deacetylation (Inalbon et al 2009 ) and galactoglucomannan degradation (Paananen et al 2010 ). Both models take into account the effect of hydroxyl ion (OH -) molality and temperature, and Inalbon et al (2009) also considered the effect of ionic strength. In most models for hot water extraction (HWE) (Mittal et al 2009 ;Borrega et al 2011 ), the effect of hydrogen ion (H + ) is not accounted for, although H + catalyzes many reactions, for instance, the deacetylation and cleavage of glycosidic bonds in carbohydrates.…”

Section: Introductionmentioning

confidence: 99%

The role of Donnan effect in kraft cooking liquor impregnation and hot water extraction of wood

2013

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In this article, a phenomenological model is proposed for alkali impregnation and hot water extraction of wood. Elementary reaction kinetics, ion exchange (IE) equilibrium, and mass transfer rates are considered in the model. IE is a consequence of the dissociation of the covalently bound uronic acid and phenolic groups in the wood fiber wall (FW). Due to this effect, the molality of cations is higher in the FW liquid than in the liquid external to the FW, whereas the opposite is true for anions. For the development of kinetic models under the participation of hydroxyl and hydrogen ions, the estimation of their molalities in these two liquid phases is crucial because of their ubiquitous presence in chemical reactions. This study applies a recently developed physicochemical modeling environment in which alkali impregnation and hot water extraction processes are considered. The simulations revealed that the IE effect is significant and affects the chemical reaction kinetics in both processes in focus. Furthermore, the IE effect does not remain constant but varies as a function of treatment time.

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The deacetylation reaction in Eucalyptus wood: Kinetics and effects on the effective diffusion

Cited by 13 publications

References 9 publications

Wood capillarity and deacetylation during eucalyptus alkaline impregnation. Sulphidity effects and comparison between transverse directions

Wood capillarity and deacetylation during eucalyptus alkaline impregnation. Sulphidity effects and comparison between transverse directions

Improved impregnation efficiency and pulp yield of softwood kraft pulp by high effective alkali charge in the impregnation stage

The role of Donnan effect in kraft cooking liquor impregnation and hot water extraction of wood

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