The Chemistry of Powder and Explosives - Sciencemadness Dot Org

264 NITRIC ESTERS
the outset, "less than half of the 16 hours sour boiling usually
employed will suffice for obtaining the desired degree of purity
when followed by alternating boils in fresh water and washes
with cold fresh water, again less than half of the amount of boiling
being sufficient." With less than 20 hours total time of
purification, he obtained results as good as are ordinarily procured
by the 52 hours of the standard method.
FIGURE 64. Boiling Tubs for Purification of Nitrocellulose.
Olsen's quick stabilization process" is the result of further
thinking along this same line and represents an ingenious application
of a simple principle of colloid chemistry. After the nitrocellulose
has been thoroughly pulped, and after the easily decomposed
cellulose sulfate, etc., have been hydrolyzed, there remains
only the necessity for removing the acid which clings to the fiber.
The acid, however, is adsorbed on the nitrocellulose, or bound to
it, in such manner that it is not easily washed away by water or
even by dilute soda solution; many boilings and washings are
necessary to remove it. Olsen has found that the acid is removed
rapidly and completely if the nitrocellulose is digested or washed
with a solution of some substance which is adsorbed by nitro-
»9 U. S. Pat. 1,893,677 (1933).