Cellulose supercritical carbon dioxide

Kinetics and rate of enzymic hydrolysis of cellulose in supercritical carbon dioxide. Korean J. Chem. Eng.,... 

Carbon dioxide explosion is a pre-treatment process that uses supercritical carbon dioxide to break down the biomass structure. In aqueous solution, carbon dioxide forms carbonic acid which depolymerizes lignocellulosic materials. As a small molecule, carbon dioxide can penetrate into the pores of the biomass better than ammonia. When carbon dioxide explodes due to the change of pressure, it breaks the cellulosic structure. This process is usually operated under high pressure but low temperature to prevent monosaccharide degradation. But in comparison to steam explosion and ammonia explosion processes, the sugar recovery yield from this process is... 

Figure 9.9. Photographs of cellulose gels according to reference [28] A - hydrogel in water B - alcogel in EtOH and C - aerogel obtained by supercritical carbon dioxide drying (with permission of Wiley-VCH Verlag GmbH Co).

Gremos S,Kekos D,Kolisis F. Supercritical carbon dioxide biocatalysis as a novel and green methodology for the enzymatic acylation of fibrous cellulose in one step. BioresourTechnol 2012 115 96-101. 

NE Aniedobe, MC Thies. Formation of cellulose acetate fibers by the rapid expansion of supercritical carbon dioxide solutions. Macromolecules 30(9) 2792-2794, 1997. 

E. Kiran and H. Pohler, Alternative solvents for cellulose derivatives Miscibility and density of cellulosic polymers in carbon dioxide + acetone and carbon dioxide + ethanol binary fluid mixtures, J. Supercrit. Fluids, 13, 135-147 (1998). 

Figure 9.5. Density of cellulose aerogels prepared by Innerlohinger et al. [19] using NMMO as a solvent and supercritical drying with carbon dioxide (redrawn on the basis of their data using different units).

Thermodynamic characteristics and physical-chemical properties of natural polymers (cellulose, starch, agar, chitin, pectin and inulin), their water mixtures and some biologically active substances extracted from vegetable substances using carbon dioxide in a supercritical state are reviewed. In addition, several aspects of practical application of thermodynamic characteristics of biologically active substances are demonstrated. 

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