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The hot water process is operated at a temperature range of 160 to 240 degrees Celsius in order to maintain the liquid phase. This is done above the normal boiling point of water to increase the solubilization of the hemicellulose and the depolymerization of polysaccharides. [22]
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
The pulping of wheat straw with 40% mixtures of acetone or ethanol with water requires 60 minutes at 180 °C to give good pulp properties. [4] Organic solvents are almost always used as a mixture with water for process considerations such as reducing the vapour pressure and lowering the pH in order to also solubilise hemicellulose.
The degradation of mannans (and many related forms of hemicellulose) has been well studied. The hydrolysis of the main mannan backbone is catalyzed by various enzymes including β-mannosidase, β-glucosidase, and β-mannase. The side chains are degraded by esterases and α-galactosidase. [1]
Next to cellulose hemicellulose is the second most abundant source of carbohydrates in a plant. [12] cellulose is a homopolymer of glucose. It is very poorly soluble in most solvents, so glucose is extracted through chemical and biological breakdown achieved by cellulolytic enzymes. [12]
Arabinoxylan is a form of the hemicellulose [1] ... is extractable in water, giving rise to soluble dietary fiber. ... components of soluble and insoluble dietary ...
Xylan (/ ˈ z aɪ l æ n /; [3] / ˈ z aɪ l ən / [4]) (CAS number: 9014-63-5) is a type of hemicellulose, a polysaccharide consisting mainly of xylose residues. It is found in plants, in the secondary cell walls of dicots and all cell walls of grasses. [5] Xylan is the third most abundant polysaccharide on Earth, after cellulose and chitin ...
The result: 1 liter of water can dissolve 1.34 × 10 −5 moles of AgCl at room temperature. Compared with other salts, AgCl is poorly soluble in water. For instance, table salt (NaCl) has a much higher K sp = 36 and is, therefore, more soluble. The following table gives an overview of solubility rules for various ionic compounds.