Cellulose Chlorine bleach

Another cheap and readily available source of cellulose is the straw of annual plants. This raw material usually contains exceptionally large quantities of mineral matter. In order to separate cellulose the chlorine process is often used. It consists in treating the cellulosic raw material (previously boiled in a 10% sodium hydroxide solution and then in water) with chlorine. The decomposition of lignin, pentosans and other substances takes place and at the same time the cellulose is bleached. Crude cellulose prepared in this way contained 80-92% of a-cellulose and about 1% of mineral matter. 

Chlorine retention is a special problem with amine and amide-containing finishes. When fabrics treated with these finishes are laundered with chlorine bleach, unsubstituted nitrogen atoms can react to form chloramines (Fig. 5.10). Chloramines hydrolyse to form hypochlorous acid that can decompose to materials that will degrade cellulose by significant strength loss and marked yellowing. DMDHEU products show less chlorine retention than do TMM or DMU products. Chlorine retention of A -methylol-based finishes is used for antimicrobial effects (Chapter 15.4 and Fig. 15.3 and 15.4). 

In addition to the hazards of heat and glass in the use of the autoclave, a special hazard deserves mention. Cellulose nitrate media such as centrifuge tubes or nitrocellulose filters can be highly reactive and can decompose explosively under the conditions of high heat and pressure present in autoclaves (82, 113). Therefore, never use the autoclave to decontaminate infectious materials present in these media instead, utilize chemical decontamination techniques. Soaking in a 10 percent aqueous chlorine bleach solution for 30 minutes has been recommended (82). 

There are several methods of manufacturing is on a commercial scale, for instance the calcination of oxalic add blended with potassium chloride, treatment of sodium chlorite with chlorine, or of sodium chlorate with sulphur dioxide in the presence of concentrated sulphuric add. Chlorine dioxide is utilized as a strong bleaching agent for cellulose, paper, flour, oils and such like, as well as a solvent for removing lignin from wood pulp. 

---