Cellulose pulping

Cellulosics. CeUulosic adhesives are obtained by modification of cellulose [9004-34-6] (qv) which comes from cotton linters and wood pulp. Cellulose can be nitrated to provide cellulose nitrate [9004-70-0] which is soluble in organic solvents. When cellulose nitrate is dissolved in amyl acetate [628-63-7] for example, a general purpose solvent-based adhesive which is both waterproof and flexible is formed. Cellulose esterification leads to materials such as cellulose acetate [9004-35-7], which has been used as a pressure-sensitive adhesive tape backing. Cellulose can also be ethoxylated, providing hydroxyethylceUulose which is useful as a thickening agent for poly(vinyl acetate) emulsion adhesives. Etherification leads to materials such as methylceUulose [9004-67-5] which are soluble in water and can be modified with glyceral [56-81-5] to produce adhesives used as wallpaper paste (see Cellulose esters Cellulose ethers). 

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). 

Oxidation of kraft pulp cellulose by aq. RUCI3 or RuO /aq. Na(ClO) or aq. 0.02 M H SOj gave oxycellulose containing carbonyl and carboxylate gronps RuO itself is also effective and is likely to be the principal catalyst [348]. The system RuClj/ Na(Br03)/aq. Na2(C03) pH 9.8 oxidised varions forms of cellnlose [349]. 

White P is mixed with hexamethylenetetramine to produce a smoke screen mixt which is also an incendiary. Al or Mg may be added to the mixt to raise flame temps or paper pulp, cellulose or high-melting hydrocarbons to produce longer burning times... 

Prolonged nitration favours the processes of degradation and oxidation, and hence also the reduction of viscosity. Schur and Hoos [78a] have nitrated wood pulp cellulose at various temperatures to attain results as follows (Table 49). 

Recently, Jessup and Prosen [89] have examined the heat of combustion of cotton cellulose and wood pulp cellulose, and of their nitrates. The data for di-and trinitrate are higher than those of Taylor and Hall, and approximate to the... 

In the following section information is given about the industrial methods of obtaining cellulosic raw materials, such as cotton and wood pulp cellulose, for the purposes of nitration. The question is discussed more extensively in special handbooks devoted to the technology of cellulose. For this reason the description that follows will be limited to general information only. 

The question of substituting wood pulp cellulose for cotton as a raw material in the production of nitrocellulose arose at the beginning of the present century due to-the big increase in nitrocellulose manufacture, which was followed by an expansion in the demand for cotton. 

A particularly acute shortage of cotton occurred in Germany during World War I, and wood pulp cellulose was widely used there for nitration, although the product was inferior in quality than that made from cotton. Towards the end of World War I (about 1918), due to the shortage of cotton in the U.S.A. (despite... 

Eventually, the problem of using wood cellulose as a nitration material was solved successfully during the interwar period, and during World War n, wood pulp cellulose was commonly used for nitrocellulose manufacture. 

The form of the cellulose affects its permeability to acid, and the retention of spent acid in the fibres. Schur and McMurtrie [4] report that wood pulp cellulose from coniferous trees retains the more acid, the larger the diameter of the cellulose fibres. 

From their experiments Naiman and Troitskii concluded that wood pulp cellulose should be subjected to specially careful purification before nitration. 

A charge of cotton or wood pulp cellulose of 11-15 kg for a small unit or 20-22 kg for a large one is immersed in the acid so that it is rapidly and evenly distributed in the basket. 

Cellulosic raw materials. Linters or wood pulp cellulose are in use as raw material for manufacturing lacquer nitrocellulose. It is essential to use very well purified and bleached raw material. Wood cellulose should contain mainly a-cellulose. The admissible pentosan content is limited to traces only, because these compounds are a source of products insoluble in organic solvents. Cellophane can also be utilized for nitration. 

Pulping [CELLULOSE] (Vol 5) cellulose from [CELLULOSE] (Vol 5) hemicellulosedunng [HEMICELLULOSE] (Vol 13) m paper recycling [RECYCLING - PAPER] (Vol 21) sodium sulfite used m [SULFURCOMPOUNDS] (Vol 23)... 

Composition, % Cotton Linters Wood pulp Cellulose Cotton Wood pulp Linters Cellulose ... 

Considering that both grafting efficiency as well as conversion in this study shows optimal values for pH 4 - 7, we have used pH 5 which favors the attachment of ferrous ion on partial cellulose xanthate and other ion exchange groups present. (The term "partial cellulose xanthates" stands for xanthates bound statistically to any component of the pulp (cellulose, hemicellulose, lignin). The importance of the presence of ferrous ions on grafting is shown in Diagrams I-II-III, which show reaction mechanism sug-... 

Orsman s Explosives. Several expls were patented in Engl by W.J. Orsman between 1896 and 1900. One was called Amvis (see Vol 1, A393-R) others were a) A mining expl obtained when one p of finely pulped cellulose or the slightly nitrated product was blended with one p of hot chlorodinitrobenzene and 20p of powdered AN (BritP of 1896—7) b) A mining expl prepd by mixing one p of lampblack with one p of DNB and 24p of powdered AN (BritP of 1899-90)... 

Methylcellulose is prepared from wood pulp (cellulose) by treatment with alkali followed by methylation of the alkali cellulose with methyl chloride. The product is then purified and ground to powder form. 

C Heitner and T Min. The Effect of Sulphite Treatment on the Brightness and Bleach-ability of Chemitermomechanical Pulp. Cellulose Chem. Technol. 21 289-296, 1987. 

GX Pan and G1 Leary. The bleachabdity of wheat straw alkaline peroxide mechanical pulp. Cellulose Chem. Technol. 34 537-547, 2001. 

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