Cotton mineral matter

Cellulose is the most abundant of naturally occurring organic compounds for, as the chief constituent of the eell walls of higher plants, it comprises at least one-third of the vegetable matter of the world. The cellulose eontent of such vegetable matter varies from plant to plant. For example, oven-dried cotton contains about 90% cellulose, while an average wood has about 50%. The balance is composed of lignin, polysaccharides other than cellulose and minor amounts of resins, proteins and mineral matter. In spite of its wide distribution in nature, cellulose for chemical purposes is derived commerically from only two sources, cotton linters and wood pulp. 

The loom state cotton fabric contains about 8-12% natural impurities of total weight of the fibre. These impurities mainly consists of waxes, proteins, pectic substances and mineral matters. In addition to this, the mechanically held impurities called motes are present containing seed-coat fragments, aborted seeds and leaves etc. that clinge to the fibre. Apart from these, the loom-state fabric is also contaminated with adventiteous oils such as machine oils, tars, greases etc. 

Cotton is the purest form of natural cellulose. Like all the vegetable tissues, it contains a small amount of mineral matter that is left as an ash after cotton is burned. The amount of ash is about 1-1.5%. The mineral matter in cotton consists of chlorides, carbonates and phosphates of potassium, calcium and magnesium. A large variation is observed in the amount of coloring matter found in cotton. The small amount of vegetable protein found in cotton is a little over 1 %. The impurity... 

Raw cotton contains, in addition to cellulose, the usual constituents of a vegetable cell. These are oil and wax, pectoses and pectins, proteins and simpler related nitrogen compounds, organic acids, mineral matter, and natural colouring matter. Cotton yarns or piece goods may contain, in addition, adventitious dirt, size, and machine oil. The approximate composition of raw cotton is as follows ... 

The nature and amount of mineral matter found in cotton depends to some extent on the composition of the soil on which it was grown. It is the residue of the salts contained in solution in the sap when the cell was still a living and growing organism. The exact nature and proportions of the salts has not been ascertained, but it can be inferred from an examination of the ash. The residue after the organic matter has been removed by combustion amounts to between 1 and 2 per cent, and analysis gives the following approximate composition (per cent) ... 

Basic colouring matters are those the solutions of which are decolorised by mineral acids and give a coloured precipitate with tannin (best in presence of sodium acetate). When acidified with sulphuric acid and shaken with ether, their solutions give up nothing to the solvent. They dye animal fibres in a neutral bath or one faintly acid with acetic acid, without a mordant, and they dye cotton in a tannin bath. Mineral acids remove them completely from the fibres on which they are fixed. 

Acid colouring matters give solutions which are not decolorised by mineral adds and are not precipitated by tannin. When their solutions, addified with sulphuric acid, are shaken with ether, the latter dissolves the colouring matter and leaves a residue when evaporated. They do not dye wool and silk in a neutral bath but do so in an acid bath (with sulphuric add) they are little suitable for cotton. 

The chemical constituents of flax are the same as those of cotton, namely, cellulose, proteins, pectins, oil, wax, mineral salts, and natural colouring matter. When purified, cellulose derived from flax is identical with that of cotton. The total extent of the impurities can be as high as 25 to 30 per cent and they are mainly pectins and pcctoses. Their complete removal presents some difficulty. 

Various formulations are provided under this heading by Terry (1893), the common factor being the likely creation of complex oiganic residues. The three recipes provided are as follows (1) Fused caustic potash is digested in alcohol, and the liquor filtered and heated till a brown powder is thrown down, which is filtered and washed with acidulated water (2) Waste cotton, peat, or brown coal, heated with an alkali (3) Farinaceous matters carbonised by mineral acids. ... 

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