The Chemistry of Powder and Explosives - Sciencemadness Dot Org

222 NITRIC ESTERS
Acetyldinitroglycerin (monoacetin dinitrate) and formyldinitroglycerin
(monoformin dinitrate) have been proposed by
Vender 38 for admixture with nitroglycerin in non-freezing dynamite.
The former substance may be prepared 39 by nitrating
monoacetin or by acetylating dinitroglycerin. The latter substance
may be procured already mixed with nitroglycerin by
warming glycerin with oxalic acid, whereby monoformin (glyceryl
monoformate) is formed, and nitrating the resulting mixture
of monoformin and glycerin. Formyldinitroglycerin has
apparently not yet been isolated in the pure state. These substances
are satisfactory explosives but are more expensive to
manufacture than dinitrochlorohydrin over which they possess
no distinct advantage, and they have not come into general use.
Tetranitrodiglycerin (Diglycerin tetranitrate)
If glycerin is heated with a small amount of concentrated
sulfuric acid, ether formation occurs, water splits out, and diglycerin
and polyglycerin are formed. If the heating is carried out
in the absence of acids, and in such a way that the water which
is formed is allowed to escape while the higher-boiling materials
are condensed and returned, especially if a small amount of
alkali, say 0.5%, or of sodium sulfite is present as a catalyst,
then the principal product is diglycerin and not more than a few
per cent of polyglycerin is formed. It is feasible for example to
convert glycerin into a mixture which consists of 50-60% diglycerin,
4-6% polyglycerin, and the remainder, 34-46%, unchanged
glycerin. The diglycerin is ordinarily not isolated in the
pure state. The mixture, either with or without the addition of
glycerin, is nitrated directly to form a mixture of tetranitrodiglycerin
and nitroglycerin which is used for the manufacture
of non-freezing dynamite.
Diglycerin when obtained pure by a vacuum distillation is a
water-white liquid, more viscous and more dense than glycerin,
sweet-tasting, very hygroscopic, b.p. 245-250° at 8 mm. It is
nitrated with the same mixed acid as glycerin, although a smaller
38 Z, ges, Schiess- u. Sprengstoffw., 2, 21 (1907). Fourth Internat. Congr.
2, 582 (1906).
39 Ger, Pat. 209,943 (1906); Brit. Pat. 9791 (1906); French Pat. 372,267
(1906); Swiss Pat. 50,836 (1910); U. S. Pat. 1,029,519 (1912).