Characterization of depolymerized cellulosic residues

Bouchard, Jean; Gil, Garnier; Vidal, P. F.; Chornet, E.; Overend, R. P.

doi:10.1007/bf00229051

Cited by 14 publications

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“…[11] Consequently, acid hydrolysis of cellulose seems to be a good choice with regard to soluble products of small chain length. Carboxylic acids are not suitable for cellulose hydrolysis because their acidity is too low for effective splitting of the glycosidic bonds.…”

Section: Introductionmentioning

confidence: 99%

Efficient Method for the Preparation of Pure, Water‐Soluble Cellodextrines

Liebert

Seifert

Heinze

2008

Macromolecular Symposia

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Summary: An efficient method towards water soluble cellodextrine mixtures is described and detailed information on structure analysis is given. For cellulose degradation in good yield, treatment of cellulose with 85% phosphoric acid for 30 minutes at room temperature and a hydrolysis of 20 hours at 55 8C are suitable. With a work up in tetrahydrofuran (THF), a yield of almost 70% raw product is achievable. After separation of a water insoluble fraction, a yield of 53% of cellodextrines with a degree of polymerization (mean weight average, DP w ) of 7.5 and a polydispersity index of 1.7 is obtained. These cellodextrines are soluble in water, dimethyl sulfoxide (DMSO) and dimethyl acetamide (DMA)/LiCl. Detailed structure analysis by one and two-dimensional NMR, FTIR and mass spectroscopy revealed that the substance consists only of b-1 ! 4 linked glucoses. A partial functionalization was excluded by 13 C NMR-and 31 P decoupled 1 H NMR spectroscopy.

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Section: Introductionmentioning

confidence: 99%

Efficient Method for the Preparation of Pure, Water‐Soluble Cellodextrines

Liebert

Seifert

Heinze

2008

Macromolecular Symposia

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“…Lastly, several researchers have found that cellulose conversion during acid catalyzed hydrolysis in batch and percolation reactors is limited to approximately 70% (Mok andAntal, 1992 andBouchard et al, 1989). The conversion ceiling can not be fully explained by the formation of degradation byproducts from glucose.…”

Section: Acid Catalyzed Hydrolysis Of Cellulosementioning

confidence: 99%

“…Therefore, a parasitic pathway has been proposed to exist in the hydrolysis of cellulose. One proposed mechanism involves the oxidative formation of a carbonyl group from the hydrogen and hydroxyl groups (Bouchard, 1989). On the molecular level, water forms a thin boundary layer with the cellulose chains due to hydrogen bonding between the hydrogens of water and the oxygen of the hydroxyl group.…”

Section: Acid Catalyzed Hydrolysis Of Cellulosementioning

confidence: 99%

“…The glucose degrades to 5-HMF almost as fast as it is liberated from the cellulose. In addition, the parasitic pathway proposed by Bouchard et al (1989) and Mok and Antal (1992) could have an increased effect with the higher severity. This will be illustrated in the discussion on furans.…”

Section: Glucosementioning

confidence: 99%

“…The missing glucose cannot be fully explained by degradation to 5-HMF alone. The parasitic pathway described by Bouchard (1989) that converts cellulose to non-reactive polymeric products plays a large role in the reduced yield. The same test is run with the solids now removed at 30 minutes to possibly This yield can be increased slightly through the reduction of furanic degradation products.…”

Section: Re-introduction Of Solids After Sugar-acid Removalmentioning

confidence: 99%

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Preliminary investigation into single stage enzyme free hydrolysis of hardwood sawdust.

Dunaway

William²

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Enzymatic hydrolysis is the most common method of producing fermentable sugars from lignocellulosic biomass. Limitations to this step include the high cost of enzymes, and the time required to process the biomass. To increase the throughput and decrease catalyst cost, the preliminary development of a continuous concentrated sulfuric acid process is explored. The process requires two distinct steps. The first step involves hydrolyzing lignocellulose to fermentable sugars, glucose and xylose. The second step consists of glucose and xylose removal from the concentrated acid stream. The separation of sugars decreases the production of reaction byproducts and allows for the recycle of acid to the process.Single stage acid hydrolysis was tested at nine different reaction conditions. The optimum reaction condition occurred at 70 weight percent acid and 80°C with 58.2 percent glucose release as a percentage of available glucan and 86.5 percent xylose release as a percentage of available xylan. Detection of xylose and glucose in solution occurred at different times. These peaks are separated by enough time to warrant continuous removal of produced glucose and xylose to limit the production of reaction byproducts. In order to optimize this reaction condition, a limit of 63 percent glucose release as a percentage of available glucan was observed.A preliminary investigation of Dowex Monosphere 99 ion exchange resin to separate glucose and xylose from 70 weight percent was performed. At the column conditions tested, the sulfuric acid caused shrinkage and deactivation of the ion exchange resin leading to inefficient separation of glucose and xylose.

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The behavior of ethylene glycol during the thermal solvolysis of cellulose

et al. 1992

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The composition of the ethylene glycol solution resulting from cellulose thermal solvolysis, to produce microcrystal‐line cellulose, has been studied. Liquid and gas chromatographic analyses showed, a) little degradation of the ethylene glycol up to 280°C, and b) an acceleration of the degradation at higher temperatures in the presence of cellulose and glucose. Solubilized compounds resulting from the cellulose depolymerization although numerous were present in too low concentrations to warrant their recovery.

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Characterization of depolymerized cellulosic residues

Cited by 14 publications

References 0 publications

Efficient Method for the Preparation of Pure, Water‐Soluble Cellodextrines

Efficient Method for the Preparation of Pure, Water‐Soluble Cellodextrines

Preliminary investigation into single stage enzyme free hydrolysis of hardwood sawdust.

The behavior of ethylene glycol during the thermal solvolysis of cellulose

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