Heterogeneous Acid Hydrolysis of Alpha-Cellulose from Sudanese Cotton

Daruwalla, E. H.; Shet, R.T.

doi:10.1177/004051756203201110

Cited by 21 publications

(8 citation statements)

References 39 publications

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“…Hydrolysis temperature, as well as the interaction between temperature and acid concentration, also play significant roles in determining median CNC length. The strong effect of temperature on CNC length is likely a result of a higher rate constant for the acid hydrolysis of cellulose [48]. Higher rate constants result in faster hydrolysis of glycosidic linkages and lower degree of polymerization of cellulose, which correlates with nanocellulose length [49].…”

Section: Resultsmentioning

confidence: 99%

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Vanderfleet

Osorio

Cranston

2017

Phil. Trans. R. Soc. A.

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Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238-475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes 'design rules' for CNCs with improved size uniformity and charge density.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.

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Section: Resultsmentioning

confidence: 99%

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Vanderfleet

Osorio

Cranston

2017

Phil. Trans. R. Soc. A.

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“…31,32 The first-order rate constant for acid hydrolysis of cellulose was evaluated by eq 2 as follows 33…”

Section: Resultsmentioning

confidence: 99%

Dilute Acid Hydrolysis of Sugar Cane Bagasse at High Temperatures: A Kinetic Study of Cellulose Saccharification and Glucose Decomposition. Part I: Sulfuric Acid as the Catalyst

Gurgel

Marabezi

Zanbom

et al. 2012

Ind. Eng. Chem. Res.

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The kinetics of sugar cane bagasse cellulose saccharification and the decomposition of glucose under extremely low acid (ELA) conditions, (0.07%), 0.14%, and 0.28% H 2 SO 4 , and at high temperatures were investigated using batch reactors. The first-order rate constants were obtained by weight loss, remaining glucose, and fitting glucose concentration profiles determined with HPLC using the Saeman model. The maximum glucose yields reached 67.6% (200°C, 0.07% H 2 SO 4 , 30 min), 69.8% (210°C, 0.14% H 2 SO 4 , 10 min), and 67.3% (210°C, 0.28% H 2 SO 4 , 6 min). ELA conditions produced remarkable glucose yields when applied to bagasse cellulose. The first-order rate constants were used to calculate activation energies and extrathermodynamic parameters to elucidate the reaction mechanism under ELA conditions. The effect of acid concentration on cellulose hydrolysis and glucose decomposition was also investigated. The observed activation energies and reaction orders with respect to hydronium ion for cellulose hydrolysis and glucose decomposition were 184.9 and 124.5 kJ/mol and 1.27 and 0.75, respectively.

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“…By equating eqs. (3) and (ll), one obtains the following expression for the parameter B/p: B / p = Zsk, Therefore, if the soluble fragments produced from hydrolysis at the ends of the particles have the same average length x , in all cellulosics, then the parameter B / p should be directly proportional to the rate constant for the production of soluble fragments. Further, if one assumes that the soluble fragments have an average length of 1 (i.e., that they are monomers and are thus single molecules of glucose), then B / p is simply the rate of hydrolysis of the glycosidic bonds at the ends of the cellulose chains.…”

Section: Correlation Between Rate Of Hydrolysis and Molecular Weightmentioning

confidence: 99%

The heterogeneous character of the dilute acid hydrolysis of crystalline cellulose

Wood

Conner

Hill

1989

J of Applied Polymer Sci

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SynopsisThe end-attack model p r o p a d by Sharples [Trcms. Furaduy Soc., 53, 1003 (1957)l for the dilute acid hydrolysis of crystalline cellulose was tested using the results from the size-exclusion chromatographic analysis of samples of crystalline cellulose I and cellulose I1 hydrolyzed in 6.1N HC1 at 107°C. The differential number distribution of the molecular weight of hydrolyzed cellulose was found to be approximately exponential, a result which is consistent with the end-attack model. Differences in the rates of hydrolysis of cellulosic materials appear to arise from differences in both the degree of polymerization and the microstructure of hydrolyzed cellulose. Evidence is also presented which suggests that the recrystallization upon hydrolysis results in part from the lateral accretion of chains which are cleaved during the hydrolysis of amorphous regions in the cellulose microfibrils.

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Heterogeneous Acid Hydrolysis of Alpha-Cellulose from Sudanese Cotton

Cited by 21 publications

References 39 publications

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Dilute Acid Hydrolysis of Sugar Cane Bagasse at High Temperatures: A Kinetic Study of Cellulose Saccharification and Glucose Decomposition. Part I: Sulfuric Acid as the Catalyst

The heterogeneous character of the dilute acid hydrolysis of crystalline cellulose

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