Partial dissolution of nitrocellulose

For the manufacture of nitrocellulose powder a volatile solvent is used, i.e. a mixture of alcohol with ether in a weight ratio of about 2 1. 

The alcohol (usually refined to 95-96%) must not be acid. To make a 100 cm3 sample of alcohol neutral towards phenolphthalein no more than 1.6 cm3 of 0.1 N NaOH is required. A larger quantity of acid is detrimental since it may adversely influence its stability and gives a dark powder. The alcohol should not contain nitrites. A nitrocellulose powder plant should be equipped with a plant for the distillation of alcohol. 

in its common commercial form, is sufficiently pure to be used in admixture with alcohol. Its acid content should not exceed 40 mg (calculated as H2S04) per litre, nor should it contain nitrites. A nitrocellulose powder plant must include a plant for the manufacture of ether. 

In France, two types of an alcohol-ether mixtures are used for the manufacture of nitrocellulose powder specified in terms of Baume degrees  

Nitrocellulose dissolves more readily in 56° ether which is therefore used more often than 54° ether. If, however, the nitrocellulose is very soluble and gives a powder with too slow a rate of burning, the use of 54° ether is recommended, i.e. a solvent which leaves more insoluble material, thus giving a more fibrous powder. 

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Soon after the manufacture of nitrocellulose smokeless powder began it was established that the powder obtained by the partial dissolution of nitrocellulose in a mixture of alcohol and ether (partly colloidal powder) has a chemical stability inferior to that of the nitrocellulose from which it derived. Thus Vieille [11] reports that on heating to a temperature of 110°C CPj guncotton undergoes denitration with the evolution of 0.04 cm3 NO/hr/gramme whereas the powder obtained from these substances without a stabilizer undergoes denitration at more than twice the rate, namely 0.10-0.15 cm3 NO/hr/gramme of substance. 

Manufacture of nitrocellulose pi wdcr The dehydration of nitrocellulose Dehydration with centrifuges Dehydration in presses RcL tification of alcohol from dehydration The preparation of nitrocellulose mixtures Partial dissolution of nitrocellulose Shaping the dough Predrying Solvent recovery... 

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