Cotton impurities

The manuf of NC is similar in that it involves the same nitrating acids as used for TNT, but used to treat cotton linters or wood pulp (raw cellulose) in a series of vats and reactors similar to the ones used for TNT. The crude NC is similarly subjected to a series of w and aq soln washes until it is finally delivered as a purified, fibrous mat — ordinarily wet with w or ale for safety. Again, there are major wastewater streams laden with spent reagents and extracted impurities... 

Compared with wool and cotton, the scouring procedures for synthetic fibres are relatively simple since these fibres contain fewer impurities. Most of these have at least some degree of water solubility the most important are sizes and lubricants. The major sizes used are poly (vinyl alcohol), carboxymethylcellulose and poly (acrylic acid), all of which are completely or partially water-soluble. Sometimes aliphatic polyesters are used. 

Unsaturated (drying) oils, like linseed oil, etc., will rapidly heat and ignite when distributed on active carbon, owing to the enormous increase in surface area of the oil exposed to air, and in the rate of oxidation, probably catalysed by metallic impurities [1]. A similar, but slower, effect occurs on fibrous materials such as cotton waste [2],... 

The principle is basically the same as any coffee pot a paper thimble is filled with the substance to be extracted (F) and a loose plug of cotton is placed (E) over the top. The Soxhlet apparatus is attached to a flask containing the proper solvent (if the solvent is not given in the formula, then usually you must find a solvent in that either the desired substance or the impurities are insoluble in). Attach a condenser to the Soxhlet tube (B). The solvent is boiled causing vapor to rise and pass through the holes (C) into the condenser where it is turned back into liquid. The liquid drops down into the thimble and solvent When the solvent level exceeds the top of the riser tube (D) the solvent overflows back into the boiling flask (G) and the process is recycled or continuous. 

Traces of water or acidic impurities can lead to the formation of insoluble, hydrated lanthanide adducts, or of paramagnetic lanthanum oxide80, adversely affecting spectral resolution. Careful purification of the solvents and substrate is advised, and filtration of the solution through glass-wool or cotton plugs may be useful. 

Impurities, such as grit, shreds of cotton, even in small quantities, sensitize an expl to frictional impact. That is why utmost cleanliness must be exercised in the preparation of expls. There are differences in the sensitivity of azides to mechanical and thermal influences. They have been correlated with the structure of the outer electronic orbits, the electrochemical potential, the ionization energy and the arrangement of atoms within the crystal. Functions of the polarizability of the cation are the plastic deformability of the crystals, and their surface properties. The nature of cation in an azide, such as Pb(Nj)2, has little effect on the energy released by the decomposition, which is vested in the N ion. The high heat of formation of the N2 molecule accounts... 

The first important invention before the invention of NC NG was the prepn in 1833 of impure Nitrostarch(NS) by Braconnot. The next step was prepn in 1838 by Pelouze of nitrated paper and cotton, but it was not realized that these were actually impure, low nitrogen content, NC s. More important than the work of the above investigators were the prepn in 1846 of NC of high N content (known as Guncotton), independently by C.F. Schonbein (1799 1866) and F. Bottger (1806 1886) and in the same year of NG by an Italian chemist Ascanio Sobrero (1812-1888). The method of prepn and some props of NG were published in France in Feb 1847 by Th-J. Pelouze (1807-1867)... 

Purified cotton consists of the fibers of different cultivated varieties of Gossypium sp. The material is freed from adhering impurities, deprived of fatty matter, bleached, and sterilized. The length of cotton fibers is up to about 5 cm, the diameter varies between 9 to 25 pm. A typical cotton fiber is cylindrical when young, but becomes flattened and twisted as it matures. The genuine cellulose wall of the cotton fiber is covered with a waxy cuticule. Delipidation is essential in order to transform the genuine fiber to absorbent cotton wool which is readily wetted by water. 

All are obtained by nitrating chlorohydrin with not overmuch concentrated nitric acid, e.g. with a threefold excess of 80% add. They can also accompany dinitro-chlorohydrin as impurities. Owing to the presence of a hydroxy group they are moderately soluble in water. In the warm they dissolve collodion cotton. Mononitrochlorohydrin has weak, but distinct explosive properties it can be made to detonate by a strong initiator though it is not exploded by impact. 

Cotton, Chemical, The basic raw material from which NC and cellulose acetate are made. Chemical cotton is chemically purified cotton linters (See under). The raw linters contain impurities such as proteins, fats, waxes, pectins, sugars, inorganic salts and mechanically entrapped vegetation, dirt, wood etc, all of which must be removed... 

When it is required to separate a solid from an impurity, it is desirable to carry out the extraction in a Soxhlet apparatus, a sketch of which is shown (Eig. 30). The substance to be extracted is placed in a paper thimble A which is set in position in the main Soxhlet tube, a loose plug of cotton wool being placed in the top of the thimble. The Soxhlet is attached to a flask B containing a small amount of a solvent the solvent chosen should be such that either the desired substance or the impurity is insoluble, or nearly so. A condenser is attached to the Soxhlet tube the ball condenser C shown in sketch is the most convenient. 

---