Organic extractives pulping

Separation of pure cellulose requires further treatment consisting of steps that include extraction with organic solvents, pulping processes, partial hydrolysis, and dissolution and reprecipitation. Because cellulose reacts with both acids and bases and is subject to oxidation, these isolation procedures can and often do degrade the cellulose. 

Anyone who has examined the chapters leading up to this one, even in the most cursory fashion, must be well aware of the role of extractives in utilizing wood. Intensity and uniformity of color affect the selection and value of fine veneers for furniture manufacture. Absence of extractives permits the invasion of microorganisms that promote sap-stain or actual wood destruction. On a positive note, absence of extractives permits pulpability by the sulfite process. Extractives harm bleached wood pulp absorptivity when used in sanitary applications such as disposable diapers. Traces of extractives in pulpmill effluents threaten the life of important marine organisms. Extractives impede pressurized wood treatment. The list could go on and on. One thing that is particularly evident about all the industrially important aspects of these effects of extractives is that they are accepted by the user simply as a fact of nature and nothing much is done about them other than the simplest sorts of physical or chemical treatment. 

Lindstrom and Schubert63 applied GC-MS, GC-MS-MS and direct inlet MS-MS to determine 1,1-dichlorodimethyl sulfone (201, DDS) in aquatic organisms outside a pulp mill bleach plant. Both GC-MS-MS and direct inlet MS-MS of tissue extracts of fish and mussel appeared to be sensitive, selective and fast techniques for the determination of DDS. 

Uses Chlorine is used for water purification and in decreasing amounts for pulp and paper bleaching. Some is used for metallurgical purposes such as metal extraction. Its largest use is for the production of organic compounds used in plastics, pesticides, herbicides, refrigeration fluids, solvents, and others. 

The pulp and paper industry is the largest industrial process water user in the U.S.5 In 2000, a typical pulp and paper mill used between 15,140 and 45,420 L (4000 to 12,000 gal) of water per ton of pulp produced. 1 2 3 4 General water pollution concerns for pulp and paper mills are effluent solids, biochemical oxygen demand (BOD), and color. Toxicity concerns historically occurred from the potential presence of chlorinated organic compounds such as dioxins, furans, and others (collectively referred to as adsorbable organic halides, or AOX) in wastewaters after the chlorination/ extraction sequence. With the substitution of chlorine dioxide for chlorine, discharges of the chlorinated compounds have decreased dramatically. 

Wood contains a small proportion (usually less than 5%) of components which are extractable by organic solvents such as ethanol or dichloromethane. The proportion of these extractives varies in hardwoods and softwoods and also between species. Although many of these substances are removed during the chemical pulping process, some may still be retained in the final sheet of paper. Their chemical composition is very varied, and they include alkanes, fatty alcohols and acids (both saturated and unsaturated), glycerol esters, waxes, resin acids, terpene and phenolic components. The proportion which remains in pulp and paper depends upon the pulping process used. In general, acidic components such as the resin and fatty acids are relatively easily removed by alkali by conversion to their soluble... 

The resin acids present in pulps, particularly those from softwood, have also been found to be significantly toxic to aquatic organisms. The amount in wood varies greatly between species (Table 10.4). Between 0.3 and 3.6 kg/tonne is extracted during pulping. 

Endoxylanase produced by a transformant strain of Escherichia coli has been shown to decrease the kappa number and increase the brightness of pulp in an enzymatic pretreatment followed by chemical extraction (27). Beta-xylosidase, on the other hand, had no effect in the treatment. The mannanase produced by Bacillus suhtilis was found to be equally effective as the xylanase. The specificities of mannanases produced by two different organisms, however, differed considerably 49). Enrichment of the culture broth of Streptomyces olivochromogenes, containing mainly endoxylanase, with different pure enzymes or enzyme mixtures acting on side chains and other hemicelluloses, resulted only in slight increases in brightness and in kappa number reduction (55). 

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