660 CREATIVE CHEMISTRY NO2, which reacts with water to produce nitric acid. Nearly all of the commercial nitric acid used in the United States today is prepared by this method. Nitric acid is one of the most important of the heavy chemicals. It reacts with many organic compounds; for example, with glycerol it forms nitroglycerol, the principal active constituent of dynamite. Incidentally dynamite was discovered by Emanuel Nobel and his son Alfred when one of their cans of nitroglycerine leaked into the kieselguhr in which it was packed. This mixture was found to be more stable than nitroglycerine and came to be known as dynamite. Nitric acid reacts with cellulose to form nitrocellulose, whose many uses will be discussed in Section 7 of this Unit. Nearly All Explosives Require Nitric Acid in Their Manufacture. The black gunpowder of our forefathers was a mixture of charcoal, sulfur, and saltpeter, KNO3. One of the earliest synthetic organic chemicals was mercury fulminate, Hg(0CN)2 (mercury fulminate is prepared from mercury, alcohol, and nitric acid), which was introduced for percussion caps in 1819. In 1865 the Prussian army used smokeless powder made from nitrocellulose and nitroglycerine. Picric acid, C6H2(OH)(N02)3, which is prepared by the action of phenol with nitric acid, came into use in the Boer and Russo-Japanese Wars for high-explosive shells; and T.N.T. was used on a large scale in the highexplosive shells of the World War of 1914r-1918. T.N.T. (trinitrotoluene), C6H2CH3(N02)3, is prepared by the action of nitric acid on toluene, CeHsCHs. A new explosive, P. E.T.N, (pentaerythritol tetranitrate), came into use during World War II. It is made from formaldehyde, acetaldehyde, and nitric acid. The Italian explosive T4 (cyclotrimethyltrinitramine) is made from formaldehyde, ammonia, and nitric acid. These two explosives are secondary explosives used for commercial blasting and as primers for high explosives. Explosives Are Widely Used for Peacetime Pursuits in the United States. To the average citizen, the word "explosives" is associated with battles and bursting shells, bomb outrages and burglars. To the quarry or mine op>erator, explosives represent a means to meet his pay-roll and pay dividends. To the engineer, they mean the second most important item in the construction of canals, the building of railroads, or the deepening of harbors, and in the production of the metal and mineral wealth, which has given the United States the dominant position it enjoys to-day. The steel industry, considered the index of business in this country because next to farming it is our greatest single industry, is dependent upon explosives for the production of its finished product. In the extensive pit mines of the
AIR AND WATER AS RAW MATERIALS 661 Mesaba Range in northern Minnesota, explosives are used to break down the coal to be made into coke for the reduction of this iron ore. In the big quarries of the lower Michigan peninsula, explosives are used to blast out solid limestone, which is subsequently crushed and shipped to the furnaces where it is used for a flux with the coke and the ore for the manufacture of iron and steel. The ships and cars that convey these raw materials to the steel mill are moved by the energy in the coal blasted down by explosives. Not only are railroad trains and tracks, ships and engines, bridges and highways, buildings and automobiles, constructed from the metals or the stone produced by the aid of explosives, but also many familiar articles of everyday life are dependent at some stage on explosives for their economical production.^ The consumption of industrial explosives in the United States averages over 1,000,000 pounds a day. Industrial Explosives Are Different from Military and Sporting Powders. To most people, explosives are simply explosives, but in the minds of manufacturers and users they are classified in two general groups: first, military and sporting powders, which are mainly propellants with some disruptives like T.N.T. for shell bursting charges, mines and bombs; and, second, industrial explosives, which are all disruptives and are in turn divided into two classes; high explosives, including dynamite, and blasting powder or the familiar gun-powder. These two groups are not interchangeable. Black powder is ruled out as a propellant in modern warfare, as the smoke produced on firing would disclose the location of the gun. Dynamite cannot be used as a propellant as its speed of detonation is so great it would shatter the gun; it cannot be used as a bursting charge in shells as the shock of shooting the shell from the gun would also set ofif the bursting charge and wreck the gun. Furthermore, bullets are usually flying around the seat of war and most dynamites would be set off if hit by a bullet. Military explosives such as smokeless powder and T.N.T. are not open to The only ingredients common to both are these criticisms, but they cannot be used in mines and quarries as they are too weak for many types of rock, the fumes from their explosions are so strong with carbon monoxide that they would be unsafe in mines, and lastly, they are much more expensive than dynamite or black powder. Not only is it impossible to use dynamite as a propellant or for shell-bursting charges, but dynamite manufacturing plants cannot be converted into smokeless powder plants in time of war. nitric and sulphuric acid. The dynamite manufacturing apparatus is entirely different, the processes and chemical composition totally unlike that of military explosives, and it takes a considerable period of time to train the personnel of both dynamite and smokeless powder plants in their specialties.* Ammonia Has Several Important Uses. Ammonia gas, NH3, reacts with water to form the weak base, ammonium hydroxide, NH4OH, which is so useful in house cleaning. > Explosives — Their Significance. Manufacture and Use, E. I. du Pont de Nemours and Company, Inc.