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FODDER CROPS
Stems and Foliage Per cent of Per cent of Per cent of
of See also:Root Crops. Fibre. Fodder Crops. Fibre.1 Cereal Straws. Fibre.
See also: 26.7 See also:Sainfoin 28.7 Leguminous. Oil Seeds. Stems and Fodder Cereal Foliage of Crops. Straws. Root Crops See also:Average % of See also:water 14 7 87 7o-8o 15 'This percentage is calculated on airdry-produce containing 15% of water. The above figures have a purely empirical value, since they represent a complicated mixture of various residues derived from the celluloses and See also:compound celluloses. This mixture may be further resolved, and by See also:special quantitative methods the See also:pro-portions of actual See also:cellulose, ligno-cellulose and cuto-celluloses estimated (J. See also:Konig, Ber., 1906, 39, p. 3564). The figures are taken as an inverse measure of digestibility; at the same See also:time it has been established that this See also:group of relatively indigestible See also:food constituents are more or less digestible and assimilable as flesh and See also:fat producers. The percentage or coefficient of digestibility of the celluloses of the more important food-stuffsgreen fodder, hay, See also:straw and grains—varies from 20 to 75%. It has also been established that their physiological efficiency is, under certain conditions, quite equal to that of See also:starch. It must also be See also:borne in mind that the indigestible food residues, as finally voided by the See also:animal, have played an important See also:mechanical See also:part as an aid to digestion of those constituents more readily attacked in the See also:digestive See also:tract of animals. They are further an important See also:factor of the agricultural See also:cycle. Re-turned `;to the See also:soil as " See also:farm-yard manure," mixed with other cellulosic See also:matter which has served as See also:litter, they add " fibre " to the soil and, as a mechanical diluent of the See also:mineral soil components, maintain this in a more open See also:condition, penetrable by the atmospheric gases, and promoting See also:distribution of moisture. Further by breaking down, with See also:production of " humus," a complex of colloidal " unsaturated " bodies of See also:acid See also:function, they fulfil important chemical functions by interaction with the mineral soil constituents. See also:Chemistry of Cellulose.—Purified See also:cotton cellulose, which is the definitive prototype of the cellulose group or See also:series, is a complex of monoses or their " residues." It is resolved by See also:solution in sulphuric acid and subsequent See also:hydrolysis of the See also:esters thus produced into dextrose. This fundamental fact with its elementary See also:composition, most simply expressed by the See also:formula C6H1005, has caused it to be regarded as a polyanhydride of dextrose. Forming, as it does, See also:simple esters in the ratio of the reacting hydroxyls 30H: C6H1„05, and taking into See also:account its See also:direct converson into w-brom-methyl furfural (See also:Fenton) a constitutional formula has been proposed by A. G. See also:Green (Zeit. Farb. Textil Chem. 3, pp. 97 and 309 (1904)), which is a useful generalization of its reactions, and its ultimate relations to the CH (OH) .CH .CH (OH) simpler carbohydrates, viz., II >0 >0 . Green See also:con- CH(OH)•CH.See also:CH2 siders, moreover, that a group thus formulated may consistently represent the actual dimensions of the reacting unit, but that unit of larger dimensions, if postulated, is easily derived from the above by See also:oxygen linkings. , From another point of view the unit group has been formu-,CH (OH) •CH(OH) fated as CO > CH2 , the See also:main linking of such See also:units in the `CH (OH) .CH (OH) complex taking See also:place as between their respective CO and CH2 See also:groups in the alternative enolic See also:form CH—C(OH). This view gives expression to the genetic relations of the celluloses to the lignocelluloses, to the tendency to See also:carbon condensation as in the formation of coals, and pseudo-carbons, to the relative resistance of cellulose to hydrolysis, and its other points of differentiation from starch, and more particularly to the ketonic See also:character of its carbonyl (CO) groups, which is also more in See also:harmony with the experimental facts established by Fenton as to the production of methyl furfural. The See also:probability, however, is that no simple molecular formula adequately represents the constitution of cellulose as it actually exists or indeed reacts. On the other See also:hand, it has been suggested that cellulose is to be regarded as representing a condition of matter analogous to that of a saline electrolyte in solution, i.e. as a complex of molecular aggregates, and of residues (of monose groups) having distinct and opposite polarities; such a complex is essentially labile and its configuration will See also:change progressively under reaction. The exposition of this view is the subject of a publication by See also:Cross and Bevan (Researches on Cellulose, ii. 1906). The main purpose is to give full effect to the colloidalcharacteristics of cellulose and its derivatives, with reference to the See also:modern theory of the colloidal See also:state as involving a particular See also:internal See also:equilibrium of amphoteric electrolytes. The typical cellulose is a white fibrous substance See also:familiar to us in the various forms of bleached cotton. Other fibrous celluloses are equally characteristic as to form and See also:appearance, e.g. bleached See also:flax, See also:hemp, See also:ramie. It is hygroscopic, absorbing 6 to 7% its See also:weight of moisture from the See also:air. When dry, it is an See also:electrical insulator, and has a specific inductive capacity of about 7: when wetted it is a conductor, and manifests electrolytic phenomenal It is insoluble in water and in the See also:ordinary solvents; it dissolves, however, in a 40-50% solution of See also:zinc chloride, and in ammoniacal solutions of See also:copper See also:oxide (3% CuO, 15% NH3): from these solutions it is obtained as a highly hydrated, gelatinous precipitate, from the former by dilution or addition of See also:alcohol, from the latter by acidification; these solutions have important See also:industrial application. Projected or See also:drawn into a precipitating solution they may be solidified continuously to threads of vatious, but controlled dimensions: the regenerated cellulose, now amorphous, in its finer dimensions is known as artificial See also:silk or lustra-cellulose. These forms of cellulose retain the See also:general characters of the See also:original fibrous and " natural " celluloses. In composition they differ somewhat by See also:combination with water (of hydration), which they retain in the air-dry condition. They also further combine with an increased proportion of atmospheric moisture, viz. up to ro-rr % of their weight. Derivatives.—Important derivatives are the esters or ethereal salts of both inorganic and organic acids, cellulose behaving as an alcohol, the highest esters indicating that it reacts as a trihydric alcohol of the formula n[C6H702(OH)3]. The nitrates result by the See also:action of concentrated nitric acid, either alone or in the presence of sulphuric acid: the normal dinitrate represents a definite See also:stage in the series of nitrates, and the ester at this point manifests the important See also:property of solubility in various alcoholic solvents, notably See also:ether-alcohol. Such nitrates are the basis of See also:collodion, of artificial silk by the processes of Chardonnet and Lehner, and of celluloid or xylonite. Higher nitrates are also obtainable-up to the limit of the trinitrate, which is insoluble in ether or alcohol, but is soluble in See also:nitroglycerin, See also:nitrobenzene and other solvents. These higher nitrates are the basis of the most important modern See also:explosives. Cellulose reacts directly with acetic anhydride to form See also:low esters; in the presence of sulphuric acid the reaction proceeds to higher limits; the triacetate is soluble in See also:chloroform. The acid sulphuric ester, C6H803(SO4H)2, is obtained by the action of sulphuric acid, but its relation to the original cellulose is doubtful. The monobenzoate and dibenzoate are formed by benzoyl chloride reacting on See also:alkali-cellulose (see below). Cellulose xanthates are obtained from carbon bisulphide and alkali-cellulose; these are water soluble derivatives and the basis of " viscose," and of important See also:industries. Mixed esters—acetosulphate, aceto-benzoate, nitrobenzoyl nitrates, aceto-nitrosulphates—have also been investigated. Cellulose (cotton), when treated with a 15-20% See also:caustic soda solution, gives the compound C6H605•H20.2NaOH, alkali-cellulose, the original riband-like form with reticulated walls of the .cellulose being transformed into a smooth-walled See also:cylinder. The structural changes in the ultimate fibre deter-mine very considerable changes in the dimensions of fabrics so treated. The reactions and structural changes were investigated by J. See also:Mercer, and are known generally as " mercerization." In See also:recent years a very large See also:industry in " mercerized " fabrics (cotton) has resulted from the observation that if the shrinkages of the yarns and fabrics be antagonized by mechanical means, a very high lustre is See also:developed. Similar, but less definite compounds, are formed with the oxides of See also:lead, See also:manganese, See also:barium, See also:iron, See also:aluminium and See also:chromium. These derivatives, which also find industrial applications in the See also:dyeing and See also:printing of fabrics, differ but little in 1 C. F. Cross and E. J. Bevan, Jour. Chem. See also:Soc., 1895, 67, p. 449; C. R. See also:Darling, Jour. See also:Faraday Soc. 1904; A. See also: appearance from the original cellulose, and are without See also:influence on its essential characteristics. Decompositions.—Hydrolysis:—By solution in sulphuric acid followed by dilution and boiling the diluted solution cellulose hydrolyses to fermentable sugars; this reaction is utilized industrially in the manufacture of See also:glucose from rags. Hydrochloric acid produces a friable See also:mass of " hydrocellulose," probably C12H22011, insoluble in water, but readily attacked by alkalis, with the production of soluble derivatives; some dextrose is formed in the original reaction. Hydrobromic acid in ethereal solution gives See also:furfurane derivatives. See also:Cold dilute acids have no perceptible action on cellulose. The actions of such acids are an important See also:auxiliary to See also:bleaching, dyeing and printing processes, but they require careful See also:limitation in respect of concentration and temperature. Cellulose is extremely resistant to the action of dilute alkalis: a 1-2% solution of See also:sodium See also:hydrate having little action at temperatures up to 15o°; hence the use of caustic soda, soda ash and sodium silicate in bleaching processes, i.e. for the elimination of the non-cellulose components of the raw See also:fibres. Oxidation in acid solutions gives compounds classed as " oxycelluloses," insoluble in water, but more or less soluble in alkalis; continued oxidation gives formic, acetic and carbonic acids. Oxidation in alkaline solution is more easily controlled and limited; solutions of bleaching See also:powder, or more generally of alkaline hydrochlorites, receive industrial application in oxidizing the coloured impurities of the fibre, or residues See also:left after more or less severe alkali treatments, leaving the cellulose practically unaffected. This, however, is obviously a question of conditions: this group of oxidants also oxidize to oxycellulose, and under more severe conditions to acid products, e.g. oxalic and carbonic acids. Certain bacteria also induce decompositions which are resolutions into ultimate products of the lowest molecular dimensions, as See also:hydrogen, carbon dioxide, methane, acetic acid and butyric acid (Omeliansky) (Handb. Techn. Mykologie [F. Lafar] pp. 245-268), but generally the cellulose complex- is extremely resistant to the organic ferments. Cellulose See also:burns with a luminous See also:flame to carbon dioxide and water; dry See also:distillation gives a complicated mixture of gaseous and liquid products and a See also:residue of See also:charcoal or pseudo-carbon. Chromic acid in sulphuric acid solutions effects a See also:complete oxidation, i.e. See also:combustion to water and carbonic acid. Ligno-celluloses.—These compounds have many of the characteristics of the cellulose esters; they are in effect ethereal compounds of cellulose and the quinonoid lignone complex, and the combination resists hydrolysis by weak alkalis or acids. The cellulose varies in amount from 8o to 50%, and the lignone varies inversely as the degree of lignification, that is, from the lignified bast fibre of annuals, of which jute is a type, to the dense tissues of the perennial dicotyledonous See also:woods, typified by the See also:beech. The empirical formula of the lignone complex varies from C19H22O9 (jute) to C261130010 (See also:pine See also:wood). In certain reactions the non-cellulose or lignone constituents are selectively converted into soluble derivatives, and may be separated as such from the cellulose which is left; for example, chlorination gives products soluble in sodium sulphite solution, by the combination of unsaturated groups of the lignone with the halogen, while digestion with bisulphite solutions at elevated temperatures (14o°-16o°) gives soluble sulphonated derivatives. This last reaction is employed industrially in the preparation of cellulose for See also:paper-making from coniferous woods. These reactions are " quantitative " since they depend upon well-defined constitutional features of the lignone complex, and the See also:resolution of the ligno-cellulose takes place with no further change in the lignone than the synthetical combination with the substituting groups. The constituent groups of the lignone specifically HC reacting are of benzenoid type of the probable form HC CO See also:H2C~C0 CO deduced from the similarity of the chlorinated derivatives to mairogallol, the product of the action of See also:chlorine on See also:pyrogallol in acetic acid solution (A. Hantzsch, Ber. 20, p. 2033)
The complex contains methoxy (OCH3) groups. There is also See also:present a residue which is readily broken down by oxidizing agents, and indeed by simple hydrolysis, to acetic acid. Another important group of actual constituents are pentosanes —partially isolated as " wood See also:gum " by solution in alkalis —and furfural derivatives (hydroxy furfurals) derived from these. 'The actual constitutional relationships of these main groups, as well as the localization of the methoxy groups, are still problematical.
Certain See also:colour reactions are characteristic, though they are in some cases reactions of certain constituents invariably present in the natural forms of the ligno-cellulose; which may be re-moved without affecting the essential character of the lignone complex. See also:Aniline salts generally give a yellow coloration, dimethyl-See also:para-phenylenediamine gives a deep red coloration, phloroglucin in hydrochloric acid gives a See also:crimson coloration. Reactions more definitely characteristic of the lignone are:—ferric ferrocyanide, which is taken up and transformed into Prussian See also:blue throughout the fibre, without affecting its structure, although there may be as much as a 50% gain in weight; See also:iodine in See also:potassium iodide solution gives a deep See also: Jute reacts with nitric acid in presence of sulphuric acid to form nitrates; and with acetic anhydride to form low acetates. It reacts with alkaline hydrates with structural changes similar to those obtained with cotton; and by the further action of benzoyl chloride and of carbon bisulphide upon the resulting compounds there result the corresponding benzoates and xanthates respectively. But these synthetical derivatives are mixtures of cellulose and lignone derivatives, and so far of merely theoretical See also:interest. Decompositions of Ligno-cellulose.—In addition to the specific resolutions above described which depend upon the distinctive chemical characters of the cellulose and lignone respectively, the following may be noted: to simple hydrolytic agents the two groups are equally resistant, therefore by boiling with dilute acids or alkalis the groups are attacked pari passu. Weak oxidants may also be used as bleaching agents to remove coloured by-products without seriously attacking the ligno-cellulose, which is obtained in its bleached form. Nitric acid of all strengths effects complete resolution. Chromic acid in dilute solutions combines with the lignone complex, but in presence of hydrolysing acids See also:total oxidation of the lignone is determined. The See also:principal products are oxalic, carbonic, formic and acetic acids. This reaction is an See also:index of constitution. Generally, the lignone is attacked under many conditions and by many reagents which are without action upon cellulose, by virtue of its unsaturated constitution, and its acid and aldehydic residues. Cuto-cellulose.—A typical cuto-cellulose is the cuticle (See also:peel) of the See also:apple which, when purified by repeated hydrolytic treatment and finally by alcohol and ether, gives a product of the composition C = 75'66%,' II= 11-37 %, 0 =14.97 %. Hydrolysis by strong alkalis gives stearo-cutic acid, C28H48O4, and oleo-cutic acid, C14H20O4 (See also:Fremy). See also:Cork is a complex mixture containing various compound celluloses: extraction with alcohol removes certain fatty See also:alcohols and acids, and aromatic derivatives related to tannic acid; the residue is probably a mixture of cellulose. ligno-cellulose, cerin, C20H320 and suberin; the latter yields stearic acid, C18H38O2, and the acid C22H42O3. The cutocelluloses have been only superficially investigated, and, with the exception of cork, are of but little direct industrial importance. Industrial Uses of Cellulose.—The applications of cellulose to the necessities of human See also:life, infinitely varied in See also:kind as they are See also:colossal in magnitude, depend upon two groups of qualities or properties, (1) structural, (2) chemical. The manufactures of See also:vegetable textiles and of paper are based upon the fibrous forms of the naturally occurring celluloses, together with such structural qualities as are expressed in the terms strength, See also:elasticity, specific gravity. As regards chemical properties, those which come. into See also:play are chiefly the negative quality of resistance to chemical change; this is obviously a See also:primary factor of value in enabling fabrics to withstand See also:wear and See also:tear, contact with atmospheric oxygen and water, and such chemical treatments as laundrying; See also:positive chemical properties are brought into play in the auxiliary processes of dyeing, printing, and the treatment and preparation in connexion with these. See also:Staple textiles of this group are cotton, flax, hemp and jute; other fibres are used in rope-making and See also:brush-making industries. These subjects are treated in special articles under their own headings and in the See also:article FIBRES. The course of industrial development in the 19th See also:century has been one of enormous expansion in use and considerable refinement in methods of preparation and manufacture. Efforts to introduce new forms of cellulose have had little result. See also:Rhea or ramie has been a favourite subject of investigation; the industry has been introduced into See also:England, and doubtless its development is only a question of time, as on the See also:continent of See also:Europe the production of rhea yarns is well established, though it is still only a relatively small trade—probably two or three tons a See also:day total production. The paper See also:trade has required to seek new See also:sources of cellulose, in consequence of the enormous expansion of the uses of paper. Important phases of development were: (1) in the See also:period of 186o to 1870, the introduction of See also:esparto, which has risen to a See also:consumption of 250,000 tons a See also:year in the See also:United See also:Kingdom, at which figure it remains fairly steady; (2) the See also:decade 187o to 1880, which saw the development of the manufacture of cellulose from coniferous woods, and this industry nbw furnishes a staple of See also:world-wide consumption, though the industry is necessarily localized in countries where the coniferous woods are available in large quantities. As a development of the paper industry we must mention the manufacture of paper textiles, based upon the production of pulp yarns. Paper pulps are worked into See also:flat strips, which are then rolled into cylindrical form, and by a final twisting See also:process a See also:yarn is produced sufficiently strong to be employed in See also:weaving. What we may See also:call the special cellulose industries depend upon specific chemical properties of cellulose, partly See also:intrinsic, partly belonging to the derivatives such as the esters. Thus the cellulose nitrates are the bases of our modern high explosives, as well as those now used for military purposes. Their use has been steadily developed and perfected since the See also:middle of the 19th century. The industries in celluloid, xylonite, &c., also depend upon the nitric esters of cellulose, and the plastic state which they assume when treated with solvent liquids, such as alcohol, amyl acetate, camphor and other auxiliaries, in which state they can be readily moulded and fashioned at will. They have taken an important place as structural materials both in useful and See also:artistic applications. The acetates of cellulose have recently been perfected, and are used in coating See also:fine wires for electrical purposes. especially in See also:instrument-making; this use depends upon their electrical properties of high insulation and low inductive capacity. Hydrated forms of cellulose, which result from treatment with various reagents, are the bases of the following industries: vegetable See also:parchment results from the action of sulphuric acid upon cellulose (cotton) in the form of paper, followed by that of water, which precipitates the partially colloidalized cellulose. This industry is carried out on " continuous " machinery, the cellulose, in the form of paper, being treated in rolls. Vulcanized fibre is produced by similar processes, as for instance by treating paper with zinc chloride V. 20solvents and cementing together a number of sheets when in the colloidal hydrated state; the goods are exhaustively washed to remover last traces of soluble electrolytes; this is necessary, as the product is used for electrical insulation. The solvent action of cupro-ammonium is used in treating cellulose goods, cotton and paper, the action being allowed to proceed. sufficiently to attack the constituent fibres and convert them into colloidal cupro-ammonium compounds, which are then dried, producing a characteristic green-coloured finish of colloidal cellulose and rendering the goods impervious to water. The important industry of mercerization has been mentioned above; this is carried out on both yarns and See also:cloth of cotton goods chiefly composed of See also:Egyptian cottons. A high lustrous finish is produced, giving the goods very much the appearance of silk. Of special importance are the more recent developments in the production of artificial fibres of all dimensions, by See also:spinning or See also:drawing the solutions of cellulose or derivatives. Three such processes are in course of See also:evolution. (1) The first is based on the nitrates of cellulose which are dissolved in ether-alcohol, and spun through fine See also:glass jets into air or water, the unit threads being afterwards See also:twisted together to constitute the See also:thread used for weaving (process of Chardonnet and Lehner). These processes were developed in the period-1883 to 1897, at which later date they had assumed serious industrial proportions. (2) The cupro-ammonium solution of cellulose is similarly employed, the solution being spun or drawn into a strong acid See also:bath which instantly regenerates cellulose hydrate in continuous length. (3) Still more recently the " viscose " solution of cellulose, i.e. of the cellulose xanthogenic acid, has been perfected for the production of artificial silk or lustra-cellulose; the alkaline solution of the cellulose derivative being drawn either into concentrated ammonium See also:salt solutions or into acid See also:baths. This product, known as artificial silk, prepared by the three competing processes, was in 1908 an established textile with a total production in Europe of about 5000 tons a year, a quantity which bids See also:fair to be very largely increased by the See also:advent of the viscose process, which will effect a very considerable lowering in the cost of production. The viscose solution of cellulose is also used for a number of industrial effects in connexion with paper-sizing, paper-coating, textile finishes, and the production of See also:book cloth and See also:leather cloth, and, solidified in solid masses, is used in preparing structural solids which can be moulded, turned and fashioned. For the special literature of cellulose treated from the general point of view of this article, the reader may consult the following See also:works by C. F. Cross and E. J. Bevan: Cellulose (1895, 2nd ed. 1903), Researches on Cellulose, i. (1901), Researches on Cellulose, ii. (1906). (C. F. Additional information and CommentsThere are no comments yet for this article.
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