Wood pulp hydrolyzed

The method to prepare carbon membranes was described from wood pulp hydrolyzed to different extents by Lie and Hagg [66], Different heating protocols were also shown. A simple, energy effective and rapid regeneration method for membranes that are conductors or semi-conductors has been developed by applying low voltage, direct current on an iron-doped carbon. 

High temperature acetylation of cellulose above 50°C produces cellulose acetate from low purity wood pulp cellulose in shorter reaction times. In a high temperature method recently disclosed (102), cellulose reacts with 200—400% acetic anhydride in the presence of <5% acid catalyst at 68—85°C for 3—20 min. After the acid catalyst is neutralized with magnesium acetate, the cellulose acetate is hydrolyzed at 120°C for two hours (103). Several modified catalyst systems have been developed for acetylation of cellulose above 90°C (89,90). 

For monitoring the extent of polysaccharide hydrolysis, l.c. methods that sepeu ate and analyze the non-fermentable oligosaccharides (d.p. 3-30) derived from cellulose, hemicellulose, and pectins are useful, and have already been described (see Section III,l,c). For determination of the monosaccharide composition of completely hydrolyzed, plant polysaccharides, l.c. is especially useful and has been applied to the compositional analysis of hydrolyzed plant fiber,wood pulps,plant cell-walls,and cotton fibers.In these representative examples, the major sugars of interest, namely, glucose, xylose, galactose, arabinose, and mannose, have traditionally been difficult to resolve by l.c. The separa-... 

Fermentation of Sulfite Waste Liquor. The sulfurous acid used in the sulfite pulping liquor causes hydrolysis of the more easily hydrolyzable components of wood, especially the pentosans in the hemicellulose. About 35 percent of the potentially fermentable sugars in the wood are hydrolyzed. However,... 

The objective of bleaching is to produce a white pulp of stable color obtained at reasonable cost and a minimum deleterious effect on the physical and chemical properties of the pulp. Inasmuch as the major chromophoric substances in wood pulps are derived from the lignin substrate, it must be chemically changed to colorless configurations in a stable form, or it must be oxidized, reduced, or hydrolyzed, rendering it soluble in aqueous solutions and so removable from the pulp. The two major methods of bleaching are based on these principles (23,24). 

Hydrolyzes wood pulp or paper to make glucose or fermentable sugars. Bagasse from spent sugar cane has significant potential. Several processes potentially can solve or alleviate waste problems. 

The carbohydrate analyses reported by Sundman, Saarnio and Gustafs-son for sulfate pulps are listed in Table XVII. These results were obtained by quantitative, paper chromatography on completely hydrolyzed samples. In another study,"" the uronic acid anhydride content of some wood pulps was determined. It was noted " that sulfate pulps prepared from hardwoods retain a considerable proportion of uronic acid, whereas sulfate pulps from softv oods may be entirely free from polyuronides. 

Derivation Reacting cellulose (wood pulp or cotton linters) with acetic acid or acetic anhydride, with H2S04 catalyst. The cellulose is fully acetylated (three acetate groups per glucose unit), and at the same time the sulfuric acid causes appreciable degradation of the cellulose polymer so that the product contains only 200-300 glucose units per polymer chain. At this point in the process the cellulose acetate ordinarily is partially hydrolyzed by the addition... 

Crystallites of cellulose have been isolated from wood pulp in this way by treatment with acid to hydrolyze and remove the amorphous regions. Typical dimensions of the remaining crystallites were 46 nm long by 7.3 mn wide, corresponding to bundles of about 100 to 150 chains in each crystallite. 

Battista (17) describes the preparation of microcrystalline cellulose by hydrolyzing wood pulp with 2.5N HCl at 105° for 15 min. followed by agitation in a Waring blender. Microciystalline cellulose is produced commercially and used in the food and pharmaceutical industries. 

The free sulfur dioxide in the sulfite pulping liquor promotes hydrolysis of the more easily hydrolyzable constituents of wood. A wood such as spruce, which contains 70.1% carbohydrate substances, of which 85.3% are potentially fermentable, gives a 50% yield of a pulp containing 97.7% carbohydrate, of which about 80% is fermentable. The... 

For the total hydrolysis of polysaccharides, trifluoroacetic acid (TFA) has important advantages over sulfuric acid. The reaction time is short and there is no need for conventional neutralization, as TFA is volatile and can be removed by evaporation. Several methods have been developed, depending on the substance to be hydrolyzed. Soluble saccharides (e.g., polyoses) can be hydrolyzed with diluted TFA, while cellulose, pulp, and wood need treatments with concentrated TFA in homogeneous solution. The presence of lignin impedes the hydrolysis of polysaccharides thus, especially for wood samples, an intensive treatment with TFA is necessary, and correction values have to be considered. Several application examples show that the hydrolysis with TFA enables a rapid quantitative determination of the composition of polysaccharides, pulps, and woods. 

Preliminary Remarks. The material to be hydrolyzed should be in a milled or pulverized condition or reduced to minute pieces. Wood and pulp samples should be extracted with ethanol-benzene and ethanol according to TAPPI-Standard T6m-59. Each method described below can be applied to 2-50 mg of material. The evaporator for removing the TFA should be kept in a hood. Contact of the acid with skin and eyes must be avoided. 

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