Part 4 (2/2)

(Hofmeister)

Cellulose is a very inert body Cold concentrated sulphuric acid causes it to swell up, and finally dissolves it, for a viscous solution

Hydrochloric acid has little or no action, but nitric acid has, and forms a series of bodies known as nitrates or nitro-celluloses Cellulose has so the ethereal salts with acids When cellulose in any for nitric acid at a low te nitryl, or the NO_{2} group, is produced The en by NO_{2} groups depends partly on the concentration of the nitric acid used, partly on the duration of the action If the most concentrated nitric and sulphuric acids are employed, and the action allowed to proceed for sohest nitrate, known as hexa-nitro- cellulose or gun-cotton, C_{12}H_{14}O_{4}(ONO_{2})_{6}, will be formed; but eaker acids, and a shorter exposure to their action, the tetra and penta and lower nitrates will be fore, _Jour Amer Chem Soc_, 1901, 23[8], 527-579, contains valuable information on this subject]

Besides the nitrate, A Luck[A] has proposed to use other esters of cellulose, such as the acetate, benzoate, or butyrate It is found that cellulose acetate for the addition of a solvent A sporting powder is proposed composed of 75 parts of cellulose nitrate (13 per cent N) mixed with 13 parts of cellulose acetate

[Footnote A: Eng Pat 24,662, 22nd Noveenerally attributed to Schonbein (1846), but Braconnot (in 1832) had previously nitrated starch, and six years later Pelouse prepared nitro-cotton and various other nitro bodies, and Dumas nitrated paper, but Schonbein was apparently the first che nitric and sulphuric acids Many chemists, such as Piobert in France, Morin in Russia, and Abel in England, studied the subject; but it was in Austria, under the auspices of Baron Von Lenk, that the greatest progress was made Lenk used cotton in the form of yarn, made up into hanks, which he first washed in a solution of potash, and then ater, and after drying dipped them in the acids The acid ht of sulphuric to 1 part of nitric acid, and were prepared some time before use The cotton was dipped one skein at a time, stirred for a few minutes, pressed out, steeped, and excess of acid re ater, then with dilute potash, and finally ater Von Lenk's process was used in England at Favershaiven up on account of an explosion (1847)

Sir Frederick Abel, working at Stowmarket and Waltham Abbey, introduced several very i these being pulping Having traced the cause of its instability to the presence of substances caused by the action of the nitric acid on the resinous or fatty substances contained in the cotton fibre, he succeeded in eli the nitro-cotton in water, and by a thorough washi+ng, after pulping the cotton in poachers

Although gun-cottons are generally spoken of as nitro-celluloses, they are more correctly described as cellulose nitrates, for unlike nitro bodies of other series, they do not yield, or have not yet done so, aen[A] The equation of the forun-cotton is as follows:--

2(C_{6}H_{10}O_{5}) + 6HNO_{3} = C_{12}H_{14}O_{4}(NO_{3})_{6} + 6OH_{2}

Cellulose Nitric Acid Gun-Cotton Water

The sulphuric acid used does not take part in the reaction, but its presence is absolutely essential to combine with the water set free, and thus to prevent the weakening of the nitric acid The acid ht of sulphuric acid of 184 specific gravity, and 1 part of nitric acid of 152 specific gravity The same mixture is also used at Stowmarket (the New Explosive Company's Works) The use of weaker acids results in the forenerally

[Footnote A: ”Cellulose,” by Cross and Bevan, ed by WR Hodgkinson, p

9]

The nitrate which goes under the naenerally supposed to be the hexa-nitrate, and to contain 1414 per cent of nitrogen; but a higher percentage than 137 has not been obtained from any sample It is al scale) to un-cotton; it is certain to contain several per cents of the soluble forms, ie, lower nitrates It often contains as much as 15 or 16 per cent, and only froen

[Footnote A: Mr JJ Sayers, in evidence before the court in the ”Cordite Case,” says he found 152 and 161 per cent soluble cotton, and 1307 and 1308 per cent nitrogen in two saun-cotton]

A whole series of nitrates of cellulose are supposed to exist, the highestthe hexa-nitrate, and the lowest the arded as the tri-nitrate, and collodion-cotton as the di-nitrate and iven as follows:--

Mono-nitro-cellulose C_{6}H_{9}(NO_{2})O_{5} = 6763 per cent nitrogen

Di-nitro-cellulose C_{6}H_{8}(NO_{2})_{2}O_{5} = 1111 ” ”

Tri-nitro-cellulose C_{6}H_{7}(NO_{2})_{3}O_{5} = 1414 ” ”

But gun-cotton is now regarded as the hexa-nitrate, and collodion-cotton as a mixture of all the other nitrates In fact, chemists are now more inclined to divide nitro-cellulose into the soluble and insoluble for that it is quite easy to make a nitro-cellulose entirely soluble in a h a percentage of nitrogen as 126; whereas the di-nitrate[A] should theoretically only contain 1111 per cent On the other hand, it is not possible to en than about 137, even when it does not contain any nitro-cotton that is soluble in ether-alcohol[B] The fact is that it is not at present possible to make a nitro-cellulose which shall be either entirely soluble or entirely insoluble, or which will contain the theoretical content of nitrogen to suit any of the above forives the following list of nitration products of cellulose:--

[Footnote A: The penta-nitrate C_{12}H_{15}O_{5}(NO_{3})_{5} = 1275 per cent nitrogen]

[Footnote B: In the Cordite Trial (1894) Sir FA Abel said, ”Before 1888 there was a broad distinction between soluble and insoluble nitro- cellulose, collodion-cotton being soluble (in ether-alcohol) and gun-cotton insoluble” Sir HE Roscoe, ”That he had been unable to en content than 137” And Professor G

Lunge said, ”Gun-cotton always contained soluble cotton, and _vice versa_” These opinions were also generally confir, and others]

Dodeca-nitro-cellulose C_{24}H_{28}O_{20}(NO_{2})_{12} = 1416 per cent

nitrogen (= old tri-nitro-cellulose) Endeca-nitro-cellulose C_{24}H_{29}O_{20}(NO_{2})_{11} = 1350 per cent

nitrogen

Deca-nitro-cellulose C_{24}H_{30}O_{20}(NO_{2})_{10} = 1278 per cent