Nitro-Glycerin Considered in its Chemical Details.
Glycerin, the base of Nitro-Glycerin, is produced from most of the
fixed oils and solid fats by the process of saponification, that is, by
treating these fatty bodies with an alkali, or other metallic oxide, in
presence of water, or with water itself at a high temperature. For many
years the Glycerin of commerce was produced from olive oil, by boiling,
in the presence of water, litharge, which yielded the well known lead
plaster or diachylon, and a sweetish liquid, which by evaporation of
the water, was found to be Glycerin; thus procured, however, it was
apt to be contaminated with lead, and therefore very objectionable
for medical purposes. The sources whence it is now procured, are, the
alkaline mother liquor of the soap works, when the soap is separated by
common salt: also the residue of the manufacture of stearic acid for
candles, by heating neutral fats with water or with steam, (Tilghmann’s
process): and the action of muriatic acid on castor oil. It is apt
to be contaminated with sulphuric acid, oxalic acid, lead, and more
generally with uncrystallizable sugars. The demand has vastly increased
of late years for medical purposes, elastic sponge, and retaining
moisture in tobacco, print works, as a preserving agent, and for
floating compasses, etc., etc.
The following are the synonyms of Nitro-Glycerin; Nitrate of Oxide of
Lipyl, (BERZELIUS); Glonoin, Mono-Nitro-Glycerin, Di-Nitro-Glycerin,
Tri-Nitro-Glycerin, (LIECKE)—Symbol, (C₆H₅,) O³, 3NO⁵; (Hydrogen = 1,
Oxygen = 8,) the equivalent or atomic weight is 147.
Pure Nitro-Glycerin is nearly colorless; usually, however, owing to
coloring matter contained in the Glycerin used in its manufacture, it
is of a light yellow-tinted color, oily, without odor, but having an
aromatic taste, Sp. Gr. 1.6 at 60°F, very insoluble in water; mixes
with alcohol (one part to four parts) and ether; it separates from
the alcoholic solution by the addition of water. A vinous taste is
perceptible to the tongue, the maxillary glands are stimulated, and
in a few minutes the individual who has tasted it from a pin’s point
for the first time, is conscious of a persistent, throbbing headache.
Slightly touching, it with the hands produces a like effect; after
a few days of frequent handling, however, the system becomes less
susceptible to these effects, and workmen constantly employed in its
manufacture are not affected by it. It is poisonous, a small quantity
being sufficient to kill a dog, (SOBRERO). It decomposes at 320°F,
giving out red vapors, and explodes at a higher temperature, or by
concussion or percussion, crashing the containing vessel; it ignites by
flame, and burns without explosion, yielding a light ethereal flame of
considerable volume.
Pure Nitro-Glycerin may be kept for a year unchanged, (De Vrij). The
writer has exposed it to frost, sun and rain, for three years, and
found it unchanged. Unless perfectly pure, however, it rapidly changes,
becoming of an orange yellow color, evolving fumes, and seems to become
a wholly differing compound, being difficult, when thus changed, to
congeal, except at a much lower temperature than 45°F, and is more
readily exploded.
It very easily decomposes by drying in a warm room with rarefied air,
(WILLIAMSON).
It is instantly decomposed when dissolved in alcohol, by adding an
alcoholic solution of caustic potash, the reaction being so violent as
to eject the mixture from the test tube.
Nitro-Glycerin in contact with the following salts: nitrates of lime,
cobalt, soda, barytes and potash; chlorides of calcium, of barium;
perchloride of iron, carbonate of lime, sulphates of potash, lime and
soda, was found unchanged after a year’s exposure.
INCOMPATIBLES: nitrate of silver precipitates black oxide of silver;
nitrate of copper gives a precipitate of peroxide of copper, the
Nitro-Glycerin remaining, however, bright and apparently unchanged. In
a solution of nitrate of mercury, there appears a white film, a bubble
of protoxide of azote, apparently adherent to the Nitro-Glycerin.
Muriate of ammonia seems to divide the Nitro-Glycerin into two
liquids, a light film supernatant, and the heavier liquid subjacent.
The action of chloride of mercury (calomel) is but very slight.
Protochloride of tin forms a precipitate of peroxide of tin, the
residuary Nitro-Glycerin reflecting light powerfully, and as brightly
as a diamond. Bichromate of potash is partly reduced to chromate.
Sulphate of copper forms a very slight precipitate of oxide of copper,
with apparently no change in the residuary Nitro-Glycerin. Sulphate of
iron decomposes it, giving a voluminous precipitate, with evolution of
nitrous fumes. Sulphuret of ammonia decomposes it, with precipitation
of sulphur. Acetate of lead, chlorine water, ferridcyanide of
potassium, cyanide of potassium, sulphocyanide of potassium, and of
mercury, nitroprusside of sodium decompose it, also the sulphurets of
iron, and potassium.
The action of tin, iron, and lead, slowly decomposing the
Nitro-Glycerin, especially in the presence of an acid, indicates that
metals having an affinity for oxygen, are the most active in promoting
decomposition, evolving at the same time nitrous fumes, or protoxide
of nitrogen, whilst the residuary Nitro-Glycerin does not seem to be
affected; with sulphuretted hydrogen, as with sulphuret of sodium,
potassium and ammonium, the action is prompt, and if these reagents be
added in sufficient quantity, the Nitro-Glycerin is wholly decomposed,
sulphur being precipitated.
Ascagne Sobrero, the discoverer of Nitro-Glycerin, says: it may be
prepared by slowly introducing syrupy Glycerin into a mixture of two
volumes concentrated sulphuric acid to one volume of nitric acid, Sp.
Gr. 1.4, dropping it in and rapidly cooling. It seems to dissolve in
this mixture without any noticeable reaction, and by pouring it into
water, the so formed Nitro-Glycerin separates from it. It is then
washed several times in water, is next dissolved in ether, and after
evaporation (dangerous work this) is finally purified over sulphuric
acid.
De Vrij recommends dissolving 100 grammes of Glycerin Sp. Gr. 1.262 in
200 c. c. of hydrated nitric acid cooled to 14°F, taking care that the
mixture never exceeds in temperature 32°F. When a homogeneous mixture
has been obtained, 200 c. c. of strong sulphuric acid are added very
gradually, taking especial care that the temperature of this mixture
never rises above 32°F. The oily Nitro-Glycerin which floats on the
surface is separated by a tap-funnel from the acid liquid (which
yields more Nitro-Glycerin on being diluted with water) and is now
dissolved in the smallest possible quantity of ether; this solution
is shaken with water, until the water no longer reddens litmus; the
ether evaporated (here take care!) and the remaining Nitro-Glycerin
heated over the water-bath till its weight remains constant. Merck,
of Darmstadt, the eminent operative chemist, found in following De
Vrij’s method, whilst evaporating the ethereal solution, and before
the temperature had reached 212°F, it was accompanied by a terrible
explosion. An accident from the same cause occurred in the laboratory
of Dr. E. Von Gorup-Besanez, and we find in “Comptes Rendus” an account
of the effects of the explosion of only 10 drops of Nitro-Glycerin,
which, by one of the pupils of that chemist, in his laboratory, were
put into a small cast-iron saucepan, and heated with a Bunsen gas
flame. The effect of the explosion was that the forty-six panes of
glass of the windows of the laboratory were smashed to atoms, the
saucepan was hurled through a brick wall, the stout iron stand on which
the vessel had been placed was partly split, partly spirally twisted,
and the tube of the Bunsen burner was split and flattened outwards.
Fortunately, none of the three persons present in the laboratory at the
time were hurt. When Nitro-Glycerin is caused to fall drop by drop on a
thoroughly red hot iron plate, it burns off as gunpowder would do under
the same conditions; but if the iron is not red hot, but yet hot enough
to cause the Nitro-Glycerin to boil suddenly, an explosion takes place.
Nitro-Glycerin is decomposed by evaporation, even in vacuo, over
sulphuric acid at ordinary temperatures (RAILTON), and when left to
itself, frequently undergoes spontaneous decomposition; but when well
purified, it may be kept for a long time without alteration (H. WATTS);
exhibits different properties, according to the manner in which it is
prepared (GLADSTONE).
Liecke in Dingler’s Polytechnical Journal, prescribes the following
formulæ for manufacturing the three several preparations,
Mono-Nitro-Glycerin, Di-Nitro-Glycerin and Tri-Nitro-Glycerin.
Mono-Nitro-Glycerin:
Glycerin 100 grammes.
Nitric acid, Sp. Gr. 1.3, 200 grammes.
Dissolve the Glycerin in the nitric acid, and then add
sulphuric acid 200 cubic centimeters.
The product should be C³H⁵O²H}
}O⁴
NO⁴H}
Di-Nitro-Glycerin:
Sulphuric acid containing 1 eq. water, two volumes,
nitric acid, Sp. Gr. 1.4, one volume; mix the above,
lower the temperature to 32°F, or below, and drop into it
Glycerin, pure, one volume.
Prod. C³H⁵O²H}
}O⁴
2NO⁴}
Tri-nitro-glycerin:
Sulphuric Acid, 3.5 parts.
Nitrate of Potash, 1 part.
cooled to 0°F, produces KO + 4SO³ + 6HO, from this the
concentrated fuming Nitric acid is separated by decantation,
and being maintained at 0°F,
Glycerin 0.8 parts is very gradually added,
producing C³H⁵O²NO⁴}
}O⁴
2NO⁴}
From the above extracts of several of the most eminent chemists of
the present day, the reader will glean, that in order to prepare this
explosive, of uniform quality, invariable in composition, free from
water, or any other impurity, it is not merely necessary to buy the
best materials, but to have at command the means of verifying their
purity before attempting its manufacture.
These points secured, viz: purity and strength of materials, i.
e., glycerin free from sugar, fatty acid, saline impurities, and a
mixture of Sulphuric Acid with Nitric Acid in due proportion, of due
percentage of the respective acids, and not more water therein, nor in
the glycerin, at one time of making, than another; the next point to
command will be, that in combining the glycerin with the acids, when
considerable heat is evolved, the heat thus evolved shall be absorbed
rapidly, so as never under any circumstances whatever, to exceed a
certain temperature. Sobrero names 32°F; otherwise, according to my
experience, very differing nitro-glycerin will result from variation of
temperature whilst mixing. Such products may be fatal to the miner,
although only affecting the manufacturer in a pecuniary sense. I am
led to emphasize these remarks from the fact that prospectuses have
been issued to tempt contractors to buy apparatus in the one case,
and offering to manufacture on the side of a railroad cutting, if
required, in another case, by parties who have no experience in the
manufacture, and who start in their new avocation, by deriding the
care, outlay and precautions that their competitors have deemed it
necessary to make, in order to secure a uniform, certain, and, for
mining purposes, perfectly safe explosive; for as the product is to be
handed over to the uneducated miner, who cannot estimate the risk he
is subjected to even if such a course occurred to him, it does seem
to me just and proper, that the controlling engineer, the intelligent
contractor, and especially the operating miner who is to handle this
explosive, should be advised, that under the term Nitro-Glycerin, very
different substances, both as regards explosive force, and liability to
spontaneous explosion, do result, unless extraordinary precautions are
adopted in the selection of the crude materials, as well as securing
uniformly low temperature throughout the process of making. Unless this
be done, decomposition sets in and is indicated by the emanation of
fumes, by the deepening of the light lemon tint to an orange yellow,
and at this point, the miner should decline using it, and require the
manufacturer to take his place, and the risks contingent on using it.
Since many of the accidents that have occurred with Nitro-Glycerin,
have been traced to leakage from the containing vessel, notably the
San Francisco accident, probably the Panama explosion, and undoubtedly
the Titusville or Enterprise explosion, besides other cases where
it leaked through the bottom of wagon and thence on to the springs,
whose hammering caused an explosion, the discovery by Granger, page
19, confirmed by the magazine explosion, page 18, teach the importance
of transporting this explosive in a solid state, that is, congealed;
there is however another reason; decomposing Nitro-Glycerin will not
solidify at 45°F, and the consumer has a ready and convenient test
for the purity of this article, by seeing to it that he invariably
purchases the explosive deliverable in a solid form. Another test is,
when exploded, in a close tunnel, the fumes or decomposed gases should
not inconvenience the miner.—Failing in either of these tests, it
may fairly be rejected as an inferior article, or should be used up
as speedily as possible, preferably by the manufacturer or his more
experienced employees, rather than by a miner who may not be fully
aware of the unnecessary risk to which he is exposed in handling impure
Nitro-Glycerin.
METHOD OF ANALYSIS.
Walter Crum[5] describes a method of analysing bodies containing nitric
acid, applicable to the nitro-compounds; when nitrate of potash is
used, it is previously purified by crystallization, and fused at little
more than its melting heat. Nitro-Glycerin, gun-cotton, etc., must be
deprived of moisture.
[5] Pharmaceutical Transactions, vol. 7, 1848, p. 27, et seq.
A glass jar eight inches long and an inch and a quarter in diameter,
is filled with and inverted over mercury; a single lump of time fused
nitrate, weighing about six grains, is let up through the mercury into
the inverted jar, and afterwards fifty grains of water. As soon as the
nitrate is dissolved, 125 grains of sulphuric acid, ascertained to be
free from nitric acid, are added. By the action of the mercury upon the
liberated nitric acid, deutoxide of nitrogen soon begins to be evolved,
and, usually in about two hours, without the application of heat,
the whole of the nitric acid is converted into that gas. Sometimes
agitation is necessary, and it is easily performed by giving a jerking
horizontal motion to the upper part of the jar. The surface of the
sulphuric acid is then marked, and three-fourths of an inch of solution
of sulphate of iron recently boiled, let up into the jar. The gas is
rapidly absorbed, except a small portion at last, which must be left
several hours to the action of the solution, or be well agitated in a
smaller tube with a fresh portion of it. No correction of the nitric
oxide has to be made for moisture, for the mixture of acid and water
employed has no perceptible vapor tension.
In one experiment, 5.40 grains of nitrate of potash
yielded 4.975 cubic inches of gas, at 60°F, and
barometer 30 inches.
The residue not absorbed by the sulphate of iron, was
0.015 cubic inch, leaving
4.96 cubic inches of nitric oxide = 1.594 grains NO²,
and which correspond to 2.869 grains nitric acid, or
53.13 of the nitrate of potash.
Four consecutive experiments yielded
53.13
53.14
53.73
53.29
———
Mean 53.32 or leaving out the third experiment.
Mean 53.19
The calculated percentage of nitric acid in nitrate of potash, the acid
being represented by 6.75, and the potash by 5.8992, is 53.36. THOMSON
gives for percentage of nitric acid in nitrate of potash 52.94, and
BERZELIUS 53.44.
Salts in powder, which are difficult to pass through mercury without
loss, may be enclosed in small glass cylinders. Nitro-Glycerin may
be made into pellets with powdered glass, and congealed at 45°F, or
simply congealed by taking great care it is not partially thawed during
manipulation.
Mr. Theron Skeel, of Albany, has furnished me with the following
extract from the Engineering Journal of the 17th Nov., 1871, being an
explanation of M. L. Hote’s method of analysing the gases produced
by the explosion of Nitro-Glycerin. He uses Ure’s graduated electric
eudiometer, made out of a green glass organic analysis tube. Introduce
into the apparatus ten centimeters of the gases evolved from water
by voltaic electricity, then introduce small globules of thin glass,
containing from five to six milligrammes of the explosive; an electric
spark being passed through the mixed gases by means of the platina
points melted in the upper part of the eudiometer, explodes the gases,
breaks the small glass globules and explodes the Nitro-Glycerin. The
gases evolved are colorless, and contain a proportion of binoxide of
nitrogen. Submitted to the proper absorbents, for moisture, binoxide of
nitrogen and carbonic acid, there remains nitrogen. Thus:
1 gramme Nitro-Glycerin gave at temp. 0 Cent.
29.7 barom. press.,
of these gases 284 c.c.
One hundred parts by volume contained
Carbonic acid, 45.72
Binoxide of Nitrogen, 20.36
Nitrogen, 33.92
———
100.00
MARTIN[6] has devised a method of ascertaining the percentage of
nitric acid, by its conversion into ammonia. Nitric acid when mixed
with sulphuric or muriatic acids, in the presence of metallic zinc,
is converted into ammonia (Gmelin I, 828). By placing some zinc in a
mixture of the two acids, there is no disengagement of gas, whilst the
nitric acid is converted into ammonia. Hydrogen in its nascent state
combines with the oxygen of the nitrogen compound, produced by the
nitric acid alone.
Metallic zinc, with dilute nitric acid, gives protoxide of nitrogen;
and by taking one equivalent of this gas and four equivalents of
hydrogen, water and ammonia may be formed.
NO + 4H = NH³ + HO.
The nitric acid, acting gradually and slowly on the zinc, is
transformed into ammonia, equivalent for equivalent. When this reaction
has ceased, then follows a disengagement of hydrogen gas from the zinc,
which is permitted for a few seconds. It now remains to ascertain
the percentage of ammonia. The ammonia may be distilled off and then
absorbed by a normal or previously ascertained quantitative solution of
oxalic acid, and afterwards to ascertain the quantity of oxalic acid
not taken up; deduct this from the original quantity contained in the
absorbing solution, and the result gives the percentage of oxalic acid
neutralized by the absorption of the ammonia; from this the ammonia
is calculated. Mohr’s apparatus for the disengagement of ammonia may
be used with advantage in this operation. See Mohr’s Traite d’analyse
chimique, supplement, p. 402, Paris, 1857.
Tilberg[7] analysed the Stockholm Nitro-Glycerin with the following
results: C³H⁵(NO²)O³ (the Carbon atoms being estimated as 12, Hydrogen
1, Oxygen 16,) and regarded it as Mono-Nitro-Glycerin.
[6] Comptes rendus, V. xxxvii, p. 947.
[7] Chemical News, March 1869, p. 151.
In proof of the fact of Nitro-Glycerin being explosive by concussion
effected at a distance, if proof were needed, I instance a small can
containing about 4 lbs. of Nitro-Glycerin left by the blaster about 350
feet from the heading, and partially protected by the rail which was
curved upwards to prevent the cars running over the dump, was exploded,
when a full charge of 16 holes was fired in the heading at the West
End of the Hoosac Tunnel. It will be noted that there could be no
heat developed 350 feet from the primary explosion, and being enclosed
in an ordinary kerosene can, it appears a striking instance of the
possibility of explosion from induced concussion.
Again, in April, 1872, a cartridge of Nitro-Glycerin was left in the
cartridge chest, containing about 2 lbs. Nitro-Glycerin, whilst 20
charges of blasting powder were fired in the heading, 200 feet distant;
the explosion of the powder was unusually heavy, and the Nitro-Glycerin
exploded, tearing the chest to pieces, fracturing the air main and
disrupting the track. This indubitably proves the explosion of
Nitro-Glycerin by concussion, and should warn every operator to be
careful to place any surplus explosive away from exploders, and as
far distant as possible from where an explosion is intended, and
particularly in such position that if it should explode, a contingency
possible, there may be no one near the vessel containing such surplus.
[8]The experiments of February 17, 1870, described by Professors Barker
and S. W. Johnson, where water and glass intervened to receive the heat
and concussion, confirm the fact of Nitro-Glycerin being explosive
by concussion, without heat or pressure; in these instances neither
heat nor pressure were admitted, yet the explosion blew the tub into
fragments, cutting off the staves level with the hoops, smashing and
fracturing the bottom of the tub on the rock serving as a pedestal, and
sending the water up so that it descended in a shower seventy feet from
the point of explosion.
[8] See abstract of Prof. Barker’s affidavit, towards the close of this
pamphlet.
It is proper I should here announce that, after a series of
experiments, during my leisure hours, extending over several years,
with nitro-mannite, nitro-sugar, nitro-dextrin, nitro-starch, and
nitro-naphthalin, with a view to obtain a homogeneous compound
convertible wholly into gaseous matter, and miscible with liquid
Nitro-Glycerin, which would not explode under ordinary conditions, I
have succeeded in obtaining such a mixture, viz.:
Nitro-Glycerin, thirty parts.
Nitro-Toluol, ten parts.
Mixed, this will not explode when struck on an anvil, burns when thrown
on to the fire, and can only be exploded with very heavily charged
exploders, containing, say, fifteen grains of fulminate, better and
more surely, however, with twenty grains. To this I know but one
drawback: it does not solidify at a moderate (45°F) temperature, and,
if the containing vessel should leak, a too frequent source of accident
with inferior Nitro-Glycerin that cannot be congealed, the nitro-toluol
is liable to evaporate, and the Nitro-Glycerin is then left with its
usually dangerous properties unimpaired.
This was patented by C. Volney, who formerly blasted for me, and for
the Lake Shore N. G. Co., and assigned to me for a consideration.
[Illustration]