A History of Research and a Review of Recent Developments

The development of low and high explosives 3
celebrated chemist of medieval times, a skilled experimentalist and a developer
of theories with their roots in Greek science and occult philosophy. Almost a
thousand years later the production of nitric acid had changed to a process
invented by the German chemist Johann Rudolf Glauber, who was born at
Karlstadt in Bavaria. He eventually settled in Holland and built a magnificent
laboratory in Amsterdam in the mid-seventeenth century where among other
things he defined the medicinal properties of Glauber’s salt. His process for
nitric acid was to heat a nitrate with concentrated sulphuric acid, but nowadays
there are several commercial processes, the most common of which use the
catalytic oxidation of ammonia. Nitric acid is very powerful and has formed
the basis of most modern explosives. In 1838 T.J.Pelouze discovered that cotton
could be converted into an extremely inflammable substance by the action of
concentrated nitric acid, and in 1845 it was shown by C.F.Schönbein that this
substance could be made into an explosive by adding sulphuric acid to the
nitric acid. Nitrocellulose was introduced as an ingredient of gunpowder in
the 1860s, and when E.A.Brown discovered in 1868 that nitrocellulose could
be exploded by a detonator the substance began to be used as a high explosive.
It is an unstable material, however, and stabilizers need to be added to convert
the substance into the more reliable explosive known as Guncotton. This is a
white, inodorous, tasteless solid that retains the structure of the cotton.
A much more far-reaching development based on nitric acid was the discovery
in 1846 by the Italian scientist A.Sobrero of nitroglycerine, made by the
treatment of glycerine with a mixture of concentrated nitric and sulphuric
acids. It was the study of nitroglycerine that introduced the name of Nobel,
first to the explosives industry, then to oil production, and then to the world
via the Nobel foundation and its prizes. Alfred Bernhard Nobel, engineer and
chemist, was born in Stockholm in 1833, and by 1867 he had combined
nitroglycerine with a diatomaceous earth, known as kieselguhr (kiesel is gravel,
hence Chesil beach in Dorset), to form dynamite. This made the commercial
use of nitroglycerine possible and was an invention of great importance. The
patenting of Guhr dynamite, as it was called, in Britain and the USA was
followed by a number of other dynamites in which nitroglycerine was mixed
with other substances capable of sustaining an explosion. These included sodium
nitrate, wood pulp, calcium carbonate and charcoal. In 1876 Nobel patented
blasting gelatin, which was the most powerful and shattering explosive of its
time, made by dissolving 7% of collodion nitrocellulose in nitroglycerine. In
1889, a few years before his death in 1896, Nobel produced ballistite, a
nitroglycerine smokeless powder which was the forerunner of cordite.
Of equal importance to his work on dynamite, Nobel also constructed the
fulminate of mercury detonator for initiating the explosion of nitroglycerine
and guncotton. Fulminate of mercury became known as an initiating or primary
explosive, because it could easily be detonated by impact, and could therefore
change ignition into detonation by shock rather than heat. These developments,
together with exploitation of the Baku oilfields, brought Alfred Nobel a fortune,