Researches on Cellulose Part 20

C. F. CROSS (Berl. Ber., 1895, 2609).

~CONSt.i.tUTION OF PECTINS.~

It is pointed out that the composition of the pectin of white currants, as given in the preceding paper, is that of the typical lignocellulose, the jute fibre. The product was isolated and further investigated by the author. It gave 9.8 p.ct. furfural on boiling with HCl (1.06 s.g.), reacted freely with chlorine, giving quinone chlorides, and with ferric ferricyanide to form Prussian blue. This 'pectin' is therefore a form of soluble lignocellulose. The 'pectic' group consequently must be extended to include hydrated and soluble forms of the mixed complex of condensed and unsaturated groups with normal carbohydrates, such as const.i.tute the fibrous lignocelluloses.

UEBER DAS PFLANZLICHE AMYLOID.

E. WINTERSTEIN (Ztschr. Physiol. Chem., 1892, 353).

~ON VEGETABLE AMYLOID.~

(p. 224) A group of const.i.tuents of many seeds, distinguished by giving slimy or ropy 'solutions' under the action of boiling water are designated 'amyloid.' They are reserve materials, and in this, as in the physical properties of their 'solutions,' they are very similar to starch. They are, however, not affected by diastase; and generally are more resistant to hydrolysis. Typical amyloids have been isolated by the author from seeds of _Tropoeolum majus, Poeonia officinalis_, and _Impatiens Balsamina_. The raw material was carefully purified by exhaustive treatment with ether and alcohol, &c.; the amyloid then extracted by boiling with water, and isolated by precipitation with alcohol. Elementary a.n.a.lysis gave the numbers C 43.2, H 6.1. On boiling with 12 p.ct. HCl it gave 15.3 p.ct. furfural; oxidised with nitric acid it yielded 10.4 p.ct. mucic acid. Specimens from the two first-named raw materials gave almost identical numbers.

_Hydrolysis._--On boiling with dilute acids these products are gradually broken down, dissolving without residue. In this respect they are differentiated from the mucilages, which give a residue of cellulose (insoluble). From the solution the author isolated crystalline galactose, but failed to isolate a pentose. Dextrose was also not identified directly.

The tissue residues left after extracting the amyloid const.i.tuent, as above described, were subjected to acid hydrolysis. A complex of products was obtained, from which galactose was isolated. A furfural-yielding carbohydrate was also present in some quant.i.ty, but could not be isolated. The original seed tissues, therefore, contain an amyloid and a hemicellulose, the latter differentiated in its resistance to water. Both yield, however, to acid hydrolysis a complex of products of similar composition and const.i.tution.

UEBER DEN GEHALT DES TORFES AN PENTOSANEN ODER FURFUROLGEBENDEN STOFFEN UND AN ANDEREN KOHLENHYDRATEN.

H. V. FEILITZEN and B. TOLLENS (Berl. Ber., 1897, 2,571).

~CARBOHYDRATE CONSt.i.tUENTS OF PEAT.~

(p. 240) An investigation of typical peats taken at successive depths showed increasing percentage of carbon, and inversely a decreasing yield of furfural. The numbers may be compared with those for _Sphagnum cuspidatum_--with C = 49.80 p.ct., and furfural 7.99 p.ct., calculated to dry, ash-free substance:

__________________________________________________ Depth at which taken C p.ct. Furfural p.ct. _______________________ _________ ________________ _ 20-100 cm. 51.08 6.93 I. 100-200 " 53.52 5.30 _ 200-300 " 58.66 3.19 _ Surface-20 " 55.47 3.40 II. 20-60 " 55.06 3.48 60-100 " 58.25 1.45 100-120 " 58.23 1.19 _ 180-200 " 57.57 1.80 _______________________ _________ ________________

_Cellulose_ was estimated by the Lange method. The yield from _Sphagnum_ was 21.1 p.ct.

From specimen I. at { 20-100 cm. 15.20 { 100-200 " 6.87

From the peat of lower depths no cellulose could be obtained.

_Hydrolysis_ (acid).--On heating with 1 p.ct. H_{2}SO_{4} at 130-135, soluble carbohydrates were obtained, amongst which mannose was identified, and galactose shown to be present in some quant.i.ty. After fermenting away the hexoses, the residue was treated with phenylhydrazine and an osazone separated. It contained 17.3 p.ct. N, but melted at 130. The substance could not be identified as an osazone of any of the yet known pentoses.

SECTION VIII. INDUSTRIAL AND TECHNICAL. GENERAL REVIEW

~The Industrial Uses of Cellulose.~

C. F. CROSS (Cantor Lectures, Soc. of Arts, 1897).

(p. 273) A series of three lectures, in which the more important industries in cellulose and its derivatives are dealt with on their scientific foundations, and by means of a selection of typical problems.

In reference to textiles, the small number of vegetable fibres actually available, out of the endless variety afforded by the plant world, is referred to the number of conditions required to be fulfilled by the individual fibre, thus: yield per cent. of harvested weight or per unit of field area, ease of extraction, the absolute dimensions of the spinning unit, and the proportion of variation from the mean dimensions; the relative facility with which the unit fibre can be isolated preparatory to the final twisting operation; the chemical constants of the fibre substance, especially the percentage of cellulose and degree of resistance to hydrolysis. It is suggested that any important addition to the very limited number fulfilling the conditions, or any great improvement in these, can only result from very elaborate artificial selection and cultural developments on this basis.

The paper making fibres are shown to fall into a scheme of cla.s.sification based on chemical const.i.tution, and consisting of the four groups: (a) Cotton [flax, hemp, rhea], (b) wood celluloses, (c) esparto, straw, and (d) lignocelluloses. Papers being exposed to the natural disintegrating agencies, more especially oxygen, water (and hydrolysing agents generally), and micro-organisms, the relative resistance of the above groups of raw materials is discussed as an important condition of value. The indirect influence of the ordinary sizing and 'filling' materials is discussed. The paper-making quality of the fibrous raw materials is also discussed, not merely from the point of view of the form and dimensions of the ultimate fibres, but their capacity for 'colloidal hydration.' This is complementary to the action of rosin, i.e. resin acids, in the engine-sizing of papers; and the proof of the potency of this factor is seen in the superior effects obtained in sizing jointly with solutions of cellulose and, more particularly, viscose and rosin. Wurster's much-cited monograph of the subject of rosin-sizing ['Le Collage des Papiers,' Bull. Mulhouse, 1878]

neglects to take into consideration the contribution of the cellulose hydrates to the total and complex sizing effect, and hence gives a partial view only of the function of the resin acids.

In further ill.u.s.tration of fundamental principles various developments in the textile industries are discussed, e.g. the bleaching of jute, cotton, and flax, and special developments in the spinning of rhea and flax.

The concluding lecture deals with later progress in the industrial applications of cellulose derivatives, chiefly the sulphocarbonate (viscose); the nitrates, in their applications to explosives, on the one hand, and the spinning of artificial fibres (l.u.s.tra-cellulose), on the other; and the cellulose acetates.

~La Viscose et le Viscoide.~

C. H. BARDY (Bull. Soc. d'Enc. Ind. Nationale, 1900, March).

This is a report presented to the Committee of Economic Arts of the above Society, dealing with the industrial progress in products obtained by means of the sulphocarbonate of cellulose (viscose).

The following developments are noted:

_Engine-sized Papers._--The viscose, by coating the fibres with regenerated cellulose hydrate, adds very much to the tensile strength of papers. Increase of 40-60 p.ct. is attainable by addition of cellulose in this form from 1-4 p.ct. on the weight of the paper.

_Viscoid._--Solid aggregates are formed by incorporating viscose with mineral matters, hydrocarbons, &c. Products are cast or moulded into convenient forms, and, after purification and sufficient ageing, are available for various structural uses.

_Paint._--The viscose is used as a vehicle for pigments, the mixture being used either as a paint or for coating papers with fine surfaces, such as required in the reproduction of photo-blocks. In these applications the extraordinary viscosity of the product conditions the economic use of the cellulose in compet.i.tion with oils, on the one hand, and organic colloids, such as gelatine, casein, &c., on the other.

By suitable alteration of the formula for making the paint a product is obtained which has an extraordinary power of removing paint from old painted surfaces. The product has been officially adopted by the French Admiralty, and receives extensive application in removing the paint from ships.

_Films._--Films are produced from the viscose itself in various ways.

Plane or flat by solidifying the viscose on gla.s.s surfaces, removing the by-products and rolling the films. The film is also produced by applying the viscose on textile fabrics, drying down, and fixing on a stenter machine, then washing away the alkaline by-products from the fixed film. A large number of industrial effects are obtained by suitably varying the mixtures applied.

_Cellulose-indiarubber._--The viscose, in its concentrated form, can be incorporated with rubber-hydrocarbon mixtures, and these mixtures can be used both as water-proofing films, as applied to textiles, or can be solidified into the cla.s.s of goods known as 'mechanicals.' The cellulose not only cheapens the mixture, but produces new technical effects.

_Spinning._--The viscose is spun by special methods, patented by C. H.

Stearn. As produced in thread form, the diameters are approximately those of natural silk. In commercial form it is a multiple thread (of 15 or more units) at from 50-200 deniers on the silk counts. It is a thread of high l.u.s.tre, and more nearly approaches the normal cellulose in chemical properties than any of the other artificial silks. It can also be spun in threads of very much larger diameter, which can be used as a subst.i.tute for horsehair, for carbonising for incandescent electric lamps, &c.

_Cellulose Esters._--These are conveniently made from cellulose, regenerated from the solution as sulphocarbonate. The tetracetate is made from this product on the industrial scale. Nitrates are conveniently made by treatment with the ordinary mixed acids. For fuller details the original report may be consulted.

VISKOS.

R. W. STREHLENERT (Svensk Kemisk Tidskrift, Stockholm, 1900, p. 185).

A report on the industrial development of viscose, covering essentially the same ground as the above.

~Ueber die Viscose.~

B. M. MARGOSCHES (Reprint from Zeitschrift fur die gesammte Textil-Industrie, 1900-01, Nos. 14-20).[11]

~Report of Committee on the Deterioration of Paper.~