Compound Celluloses - cellulose, wood, materials, acid, acetate, acids and products

COMPOUND CELLULOSES The celluloses from the cell walls of the phanerogams are generally associated with incrustants of complicated structure : e.g., with pectins to form pecto-celluloses; with lignone to form ligno-celluloses; and with fatty acids to form adipo- or cuto celluloses. These cellulosic materials are usually called "compound celluloses." Pecto-celluloses.—The pectins with which cellulose is asso ciated are complicated substances containing less carbon and more oxygen than cellulose itself and their properties resemble those of the oxy-celluloses. The typical pecto-cellulose is flax fibre (linum usitatissimum).

Ligno-celluloses.

The typical ligno-cellulose of simplest type is jute fibre (corcliorus). Ligno-celluloses constitute the main substance of the wood of trees. A great deal of work has been done in investigating the constitution of lignone after its separa tion from cellulose: its constitution in situ must be, of course, different. In the product obtained by the action of sulphurous acid on spruce wood various reactions indicate the presence of such groupings as C21H15O2(SO3H) (CHOH) (CHO) The is probably a complex of multiple ring nuclei of benzene type. Chlorine reacts with the lignone of jute to form chlorides of constant composition C1flH18C1200 and C1flH1sC1409 the latter of which reacts with sodium sulphite solu tion to form a soluble substance of characteristic magenta-red colour. Cellulose is thus isolated ; and this is the standard method commonly employed for the evaluation of cellulose content in raw materials and known as "cellulose by chlorination." Indus trially, the removal of lignone is of immense importance in the manufacture of pulp from wood, for the paper industries: the three important processes being the so-called "bisulphite," "soda" and "sodium sulphate" processes.

Adipo- or Cuto-celluloses.

These compound celluloses are resolved by alkali-saponification into cellulose and a mixture of fatty acids of peculiar and little known constitution ; among which, however, such acids as stearic acid may be ingredients. They occur chiefly, but by no means solely, in corticular and cuticular tissues, leaves and stems.

Decomposition Products of Celluloses.

The formation of coal and the distillation of wood are special decompositions, dealt with in the articles COAL and WOOD DISTILLATION. The hydrolysis of cellulose by acids has been mentioned above. Oxalic acid is pre pared industrially by fusing sawdust with a mixture of sodium and potassium hydroxides in flat, iron pans and, from the mixed salts of oxalic acid thus obtained, the free acid is prepared by subsequent treatment. The bacterial decomposition of cellulose, known for a long time in connection with the digestive processes of the Herbivora, in the decompositions of sewage and marshland and in the processes of soil humus, have latterly attracted new interest, with the object of bringing them under productive con trol. Methane producers, hydrogen producers, denitrifiers and thermophilic species of organisms are known among the bacteria that attack cellulose ; and in some instances attempts have been made to make industrial applications of their action. It is said that cellulose is not essentially more resistant to bacterial attack than are starches and sugars and the products obtained from its decomposition are closely related to conditions : thus, with limited aeration acetic acid is the main product, whereas, increased aera tion favours the production of ethyl alcohol. Deterioration of quality in badly stored cellulose materials, the decay of wood and the formation of coal are no doubt related to these general phe nomena. An aerobic organism isolated from Rothamsted soil decomposes cellulose rapidly with formation of a yellow pigment, fatty acids and a mucilage resembling pectin, at an optimum temperature of 3o°C.: other carbohydrates do not support growth. These facts have been applied to the preparation of synthetic farmyard manure, and other artificial fertilizers, from garden refuse.

Cellulose in the Arts and Industries.—This is the age of cellulose as much as it is the age of iron and steel: e.g., cotton is now the basis of the largest item of international trade. The cel lulose material of British industries is mostly exotic : practically, a small proportion of the wood for structural work is home grown and a considerable proportion of the flax of the linen industry: within the Empire a very large proportion of the world's jute crop is produced, about 12% of the cotton used in British mills and much wood and pulp. The applications of cellulose and cellulose materials to the necessities, amenities, and luxuries of modern life may be classified as follows: A. CELLULOSE AND COMPOUND CELLULOSE MATERIALS: (a) Foodstuffs: The foodstuffs of animals, and therefore of man, are produced ultimately by plants; but the average plant turns most of its sugars not into starch which is digestible but into cellulose which is not; hoofed animals, however, harbour in their digestive tracts bacteria that attack cellulose, on the decomposition products of which the animals live ; and hence it is through their flesh that cellulose becomes ultimately a source of food for man.

(b) Textiles: Fine:—Cotton, flax (hemp, ramie) for clothing, dress and other decorative materials.

Coarse:—Lower grades of the above and also especially jute for wrappings, balings, mattings and coverings of all kinds.

Manila, sisal, phormium for cordage, ropes and twines.

Miscellaneous:—Cereal straws, wood materials (canes), raffia, for hat-making, basket work. Coir, bast, kapok, for mat making, stuffing, packing and upholstery.

(c) Paper Making:—Many of the above materials, usually the wastes of other arts and industries, are used up for the manufacture of paper, straw boards, papier mache. Pulps from wood and grasses (e.g., esparto) .

(d) Constructional:—Timber structures, carpentry, joinery, cabinet making (woods) .

(e) Linoleum and Cork Industries.

B. CELLULOSE

the esters or reverted cellulose.

(a) Explosives:—Tri-nitro cellulose.

(b) Artificial silks:—Chardonnet, collodion or nitro-artificial silk; cuprammonium silk ; viscose silk; acetate silk.

(c) Films, tissues:—Celluloid, inflammable film made from nitro cellulose ; acetate, non-inflammable film made from cell ulose acetate ; Cellophane, wrapping tissue made from viscose; bottle-caps (hermetic closure) from viscose. Safety glass, a three-ply material made by cementing nitro or acetate film between two sheets of glass.

(d) dissolved in special solvents with special softeners, pigmented and applied by brush, or patent sprayer, for motorcar bodies and other high-class work out-of-doors; cellulose acetate, used similarly, espe cially as "dope" for aeroplane wings, to which it gives a shrunk finish and is also non-inflammable.

(e) Plastic masses for moulded articles:—Nitro-cellulose often mixed with camphor, pigments and other substances in great variety—celluloid. Also cellulose acetate as lon arite.

(f) Waterproofing and sizing of fabrics:—Willesden goods by the cuprammonium process, of military, webbing-equipment by the viscose process; artists' canvases and other fabrics, by viscose. Vulcanized fibre, from paper hydrated by zinc chloride or other solution.

C. DECOMPOSITION PRODUCTS OF CELLULOSE AND COMPOUND CEL LULOSE.

(a) Coal.

(b) Wood distillation products :—Oxalic acid.

See PLANTS : PHYSIOLOGY ; ANATOMY ; CYTOLOGY.

BIBLIOGRAPHY:—C. F. Cross and E. J. Bevan, Cellulose and ReBibliography:—C. F. Cross and E. J. Bevan, Cellulose and Re- searches on Cellulose (1895-191o) : pioneer work in the chemistry of cellulose; A. W. Schorger, Chemistry of Cellulose and Wood (1926) full account of chemistry of cellulose, more particularly wood cellulose; A. J. Hall, Cotton Cellulose (1927) : full account of cotton cellulose; W. Fuchs, Die Chemie des Lignins (1926) : the authoritative mono graph on lignone and lignification ; A. C. Thaysen and H. J. Bunker, The Microbiology of Cellulose (1927) : monograph on the action of organisms on cellulose. (C. J. J. F.)