Changes in H-Bonding of Cellulose During Solvent Purification Treatment (Acetonation)

Awadel-Karim, S.; Leclerc, D.; Grondey, H.; Yatich, S. K.; Nazhad, Mousa M.; Paszner, L.

doi:10.1515/hfsg.1998.52.1.67

Cited by 8 publications

(9 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This observation strengthens our speculation that the interaction of acetone with the cellulose hydroxyls is the principal factor responsible for bringing about irreversible structural changes within the cellulosic material as demonstrated in an earlier communication (Awadel-Karim et al 1998).…”

Section: Effect Of Type Of Acid Catalyst and Acid Concentration On Crsupporting

confidence: 91%

“…This might be attributed to the small quantities of amorphous cellulose hydrolyzed at different acetone concentrations during the solvent purification treatment of cotton cellulose. On the other hand, the systematic increase in crystallinity index of the residual cotton (Table 1), as the acetone content was successively increased in the treatment, correlates well with the progressive loss of the hydrogen bond strength of the cellulose reported (Awadel-Karim et al 1998) earlier. This explicitly means that within the prevalence of selective removal of amorphous cellulose, a higher degree of crystallinity can be attained in a more accessible cellulose.…”

Section: Effect Of Acetone On Crystallinity and Crystallite Size Of Csupporting

confidence: 83%

“…This means, the high ratio of acetone in the solvent composition (> 80 %) might bring about the following consequences; predominance of acetone in the reaction with cellulose, and stereochemical changes. The validity of this speculation has been reported in a previous communication (Awadel-Karim et al 1998). Hence, both inter-and intramolecular hydrogen bonds are expected to be affected irreversibly due to these reactions.…”

Section: Introductionsupporting

confidence: 76%

“…This may virtually lead to a permanent lattice distortion or reorientation of hydrogen bonding on the cellulose as suggested by Milichovsky (1990). This notion has been evidenced by the irreversible changes in hydrogen bonding of cotton residues reported by (Awadel-Karim et al 1998) in a previous publication, and may also be responsible for hornification of all paper pulps on drying.…”

Section: Effect Of Acetone On Crystallinity and Crystallite Size Of Cmentioning

confidence: 64%

See 3 more Smart Citations

Factors Affecting Crystalline Structure of Cellulose during Solvent Purification Treatment

Awadel-Karim¹,

Nazhad²,

Paszner³

1999

Holzforschung

Self Cite

View full text Add to dashboard Cite

The influence of acetone, as a solvent on crystalline structure of the cellulose, was investigated. Crystalline changes brought about by the solvent treatment on the residual cellulose have been found to be noticable. The crystallinity index of solvent treated celluloses has shown a trend of a small gradual increase with the progressive increase of acetone concentration in the treatment. The crystallite size of the residual cellulose has also been found to decrease successively with the increase of acetone content in the solvent composition. While the decrease in crystallite size reached approximately 8 %, the equivalent weight loss was only about 0.9 %. The influence of kinetic parameters on crystalline structure of cellulose during solvent purification (e.g., temperature, reaction time, acidity and type of acid catalyst) was also examined. Acidity and acid catalyst type were found to contribute to crystalline structural changes of cellulose. The use of higher concentrations for acids (TFA, HCl) has led to a decrease in crystallite size and crystallinity index. However, lower concentrations of TFA have a positive impact on the crystallinity index of the treated cotton cellulose. The crystallinity index of the residual cellulose has shown a slight increase with the increase in temperature, while the crystallite size has indicated a successive decrease. The reaction time has offered, in general, better chances for enhancement of the crystallinity index of the cellulose.

show abstract

Section: Effect Of Type Of Acid Catalyst and Acid Concentration On Crsupporting

confidence: 91%

Section: Effect Of Acetone On Crystallinity and Crystallite Size Of Csupporting

confidence: 83%

Section: Introductionsupporting

confidence: 76%

Section: Effect Of Acetone On Crystallinity and Crystallite Size Of Cmentioning

confidence: 64%

See 2 more Smart Citations

Factors Affecting Crystalline Structure of Cellulose during Solvent Purification Treatment

Awadel-Karim¹,

Nazhad²,

Paszner³

1999

Holzforschung

Self Cite

View full text Add to dashboard Cite

show abstract

“…1. The acetone took longer to evaporate, giving it time to covalently react with the cellulose, as documented by Awadel ‐ Karim et al [1998]. The peaks associated with the contaminated samples are characteristic of the methyl groups associated with acetonation/acetylisation of cellulose [ Awadel ‐ Karim et al , 1998].…”

Section: Discussionmentioning

confidence: 99%

Experimental assessment of the purity of α‐cellulose produced by variations of the Brendel method: Implications for stable isotope (δ¹³C, δ¹⁸O) dendroclimatology

Brookman

Whittaker

2012

Geochem Geophys Geosyst

View full text Add to dashboard Cite

[1] Stable isotope dendroclimatology using a-cellulose has unique potential to deliver multimillennial-scale, sub-annually resolved, terrestrial climate records. However, lengthy processing and analytical methods often preclude such reconstructions. Variants of the Brendel extraction method have reduced these limitations, providing fast, easy methods of isolating a-cellulose in some species. Here, we investigate application of Standard Brendel (SBrendel) variants to resinous soft-woods by treating samples of kauri (Agathis australis), ponderosa pine (Pinus ponderosa) and huon pine (Lagarastrobus franklinii), varying reaction vessel, temperature, boiling time and reagent volume. Numerous samples were visibly 'under-processed' and Fourier Transform infrared spectroscopic (FTIR) investigation showed absorption peaks at 1520 cm À1 and $1600 cm À1 in those fibers suggesting residual lignin and retained resin respectively. Replicate analyses of all samples processed at high temperature yielded consistent d 13 C and d 18 O despite color and spectral variations. Spectra and isotopic data revealed that a-cellulose d 13 C can be altered during processing, most likely due to chemical contamination from insufficient acetone removal, but is not systematically affected by methodological variation. Reagent amount, temperature and extraction time all influence d 18 O, however, and our results demonstrate that different species may require different processing methods. FTIR prior to isotopic analysis is a fast and cost effective way to determine a-cellulose extract purity. Furthermore, a systematic isotopic test such as we present here can also determine sensitivity of isotopic values to methodological variables. Without these tests, isotopic variability introduced by the method could obscure or 'create' climatic signals within a data set.

show abstract

Pretreatment and Primary Refining of Lignocelluloses

Chen

2014

Biotechnology of Lignocellulose

View full text Add to dashboard Cite

Changes in H-Bonding of Cellulose During Solvent Purification Treatment (Acetonation)

Cited by 8 publications

References 29 publications

Factors Affecting Crystalline Structure of Cellulose during Solvent Purification Treatment

Factors Affecting Crystalline Structure of Cellulose during Solvent Purification Treatment

Experimental assessment of the purity of α‐cellulose produced by variations of the Brendel method: Implications for stable isotope (δ¹³C, δ¹⁸O) dendroclimatology

Pretreatment and Primary Refining of Lignocelluloses

Contact Info

Product

Resources

About

Changes in H-Bonding of Cellulose During Solvent Purification Treatment (Acetonation)

Cited by 8 publications

References 29 publications

Factors Affecting Crystalline Structure of Cellulose during Solvent Purification Treatment

Factors Affecting Crystalline Structure of Cellulose during Solvent Purification Treatment

Experimental assessment of the purity of α‐cellulose produced by variations of the Brendel method: Implications for stable isotope (δ13C, δ18O) dendroclimatology

Pretreatment and Primary Refining of Lignocelluloses

Contact Info

Product

Resources

About

Experimental assessment of the purity of α‐cellulose produced by variations of the Brendel method: Implications for stable isotope (δ¹³C, δ¹⁸O) dendroclimatology