TEMPO-Mediated Oxidation of Cellulose III

Perez, Denilson da Silva; Montanari, Suzelei; Vignon, M.R.

doi:10.1021/bm034144s

Cited by 326 publications

(208 citation statements)

References 23 publications

Supporting

Mentioning

197

Contrasting

Unclassified

Order By: Relevance

“…Typical titration curves are shown in Figure 1. These curves, which present a remarkable reproducibility, allow us to calculate the amount carboxyl groups and therefore the degree of oxidation (DO), which is given by the following equation (da Silva Perez et al 2003),…”

Section: Conductimetrymentioning

confidence: 99%

“…The use of this technique has been attracting a number of investigations since the first reports of De Nooy et al (1994), which showed that only the hydroxymethyl groups of polysaccharides were oxidized, whereas the secondary hydroxyls remained unaffected. For cellulose, the TEMPO-mediated oxidation was applied to different cellulose samples, ranging from cotton linters, to wood pulp, parenchyma cell cellulose, rayon and cellulose III (Isogai and Kato 1998;Tahiri and Vignon 2000;Araki et al 2001;da Silva Perez et al 2003;Saito and Isogai 2004;Montanari et al 2005;Saito et al 2005Saito et al , 2006. These studies have led to the preparation of a series of products, ranging from water-soluble polyuronic acid to partially derivatized cellulose products.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

TEMPO-mediated surface oxidation of cellulose whiskers

2006

Self Cite

View full text Add to dashboard Cite

Cellulose whiskers resulting from HCl acid hydrolysis of tunicin were subjected to TEMPO-mediated oxidation under various conditions and the extent of the resulting oxidation was characterized by Fouriertransform infrared spectroscopy (FT-IR), conductimetry, X-Ray diffraction analysis and transmission electron microscopy (TEM). With degree of oxidation of up to 0.1 the samples kept their initial morphological integrity and native crystallinity, but at their surface the hydroxymethyl groups were selectively converted to carboxylic groups, thus imparting a negative surface charge to the whiskers. When dispersed in water these oxidized whiskers did not flocculate and their suspensions appeared birefringent when viewed between cross polarizers, thus indicating a liquid crystalline behavior.

show abstract

Section: Conductimetrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

TEMPO-mediated surface oxidation of cellulose whiskers

2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…The carboxylic acid content of the oxidized CNCs was determined by acid-base titration following the procedure developed for the conductometric titrations of such materials. 36 In this procedure TEMPO-oxidized CNC samples (50 mg) were suspended into 0.01 M hydrochloric acid (HCl) solutions (15 mL) with stirring. The resulting suspensions were then titrated with 0.01 M sodium hydroxide (NaOH) solution.…”

Section: Synthesis Of Click Product (Cnc-click)mentioning

confidence: 99%

“…The degree of oxidation (DO) values were calculated as already published, and very reproducible results were obtained. 36 Elemental Analysis. The percent carbon (C), hydrogen (H), and nitrogen (N) contents (%) of the unreacted TEMPO-oxidized cellulose nanocrystals, its alkyne and azido derivatives, and click product were determined by Perkin-Elmer element analyzer (Norwalk, CT).…”

Section: Synthesis Of Click Product (Cnc-click)mentioning

confidence: 99%

Regular Linking of Cellulose Nanocrystals via Click Chemistry: Synthesis and Formation of Cellulose Nanoplatelet Gels

2010

View full text Add to dashboard Cite

Over a number of years work in our laboratory has been developing new chemistry for the use of cellulose nanocrystals (CNCs) as scaffolds for the creation of nanomaterials with novel, stimuli responsive characteristics. Our work takes advantage of the rigid nature of CNCs, the unique nanopattern etched on their surface in the form of regularly spaced primary OH groups, and the fact that these materials have all reducing end groups located on one end. In this communication, a method for the grafting of amine-terminated monomers onto surface-modified CNCs followed by click chemistry is demonstrated. Initially the primary hydroxyl groups on the surface of the CNCs were selectively activated by converting them to carboxylic acids by the use of TEMPO-mediated hypohalite oxidation. Further reactions using the activated TEMPO-oxidized CNCs were carried out via carbodiimide-mediated formation of an amide linkage between precursors carrying an amine functionality and the carboxylic acid groups on the surface of the TEMPO-oxidized CNCs. Subsequently, two sets of CNCs were prepared, containing on their surface an azide derivative and an alkyne derivative, respectively. Finally, the click chemistry reaction, that is, the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition between the azide and the alkyne, surface-activated CNC was employed, bringing together the nanocrystalline materials in a unique regularly packed arrangement demonstrating a degree of molecular control for creating these structures at the nano level.

show abstract

“…Sodium hydroxide solution was added continuously to maintain the pH (Saito et al 2006). During oxidation of alcohols, da Silva Perez et al (2003) controlled the reaction by adding sodium hypochlorite solution drop by drop. The problem of buffer capacity of the borax buffer was solved with the method of da Silva Perez.…”

Section: Introductionmentioning

confidence: 99%

Influence of Buffer Solution on Tempo-Mediated Oxidation

Xu¹,

Sun²,

Wang³

et al. 2012

BioResources

View full text Add to dashboard Cite

TEMPO-mediated oxidation has been reported to effectively convert C6 primary hydroxyl groups to carboxyl groups for better water-solubility. However, the pH decreases continuously during the oxidation process, and it is therefore difficult to maintain the stability of the reaction. The control of pH at a constant level throughout the oxidation process is a complicated task. The applicability of a carbonate buffer system and a borax buffer system with various continuous addition rate of sodium hypochlorite solution was considered. Carbonate buffer solution and borax buffer solution can efficiently buffer the pH. The results of carboxyl content and DP of celluloses proved that the activities of sodium hypochlorite solution can be maintained when sodium hypochlorite is added with controlled flow rates without adjusting pH by hydrochloric acid. Buffer solutions created a milder reaction environment in which the damage of celluloses would be buffered. The conclusion was consistent with DP tests of celluloses. Compared with carbonate buffer, the borax buffer with high ability of penetration could enhance the depth and width of oxidation, which was demonstrated by the results of X-ray diffraction patterns and carboxyl content of celluloses.

show abstract

TEMPO-Mediated Oxidation of Cellulose III

Cited by 326 publications

References 23 publications

TEMPO-mediated surface oxidation of cellulose whiskers

TEMPO-mediated surface oxidation of cellulose whiskers

Regular Linking of Cellulose Nanocrystals via Click Chemistry: Synthesis and Formation of Cellulose Nanoplatelet Gels

Influence of Buffer Solution on Tempo-Mediated Oxidation

Contact Info

Product

Resources

About