I’m sure that many of were inspired to some extent by fascination with explosions, and things that go bang in the night. Generations of chemistry teachers have used the thrills of “boom” chemistry to enliven their classes and demonstrations. Those of us fortunate to have witnessed the class demonstrations of Hubert Alyea at Princeton (documented in a long series of articles in J. Chem. Ed.) were inspired to teach using those methods or just plain enjoyed them. Whatever your vocation, either in or outside of chemistry, this book makes an enjoyable and informative read.
In the Introduction, the author states that although well researched, the book is not intended for scholarly research. The history of explosives parallels the history of chemistry for the most part. There are no footnotes but the papers and patents cited can be found online. Most chemical compounds have structures illustrated or computer-generated solid models. The Introduction also covers the units of measurement used and definitions of types of explosions and explosives. Not much is known about the author other than that he has written ten other books popularizing science and has a website www.scitoys.com.
The book’s 22 chapters cover specific explosives, uses, or groups of explosives. Chapter 1 begins with a bang with the development of black powder which originated in China in the 7th century. Black powder is a mixture of nitrates, sulfur, and charcoal. Early uses were for fireworks and rapidly evolved for military uses including bombs, rockets, and fire lances. Preparation of the ingredients is described, especially the nitrates. I’ve always been curious how nitrates were acquired pre-synthetic versions. The chief sources were from processing manure and compost heaps and some recipes from the American Civil War are given.
The extension of black powder to guns and cannons is covered in Chapter 2 and development once again began in China in the 13th Century. About the same time, gunpowder was first described in England and within a hundred years, firearms were used in the Hundred Years War. Cannons began appearing in European warfare within a hundred years after that. The evolution of handheld firearms and ammunition is described in detail.
The first high explosives, metallic fulminates, are described in Chapter 3. They are high-energy compounds of carbon, nitrogen and oxygen and are typically shock sensitive. There was a pervasive need for better ways to shoot firearms than by flintlocks and their predecessors so the application of fulminates to percussion caps and eventually cartridges for initiation of firing the weapon proceeded rapidly. The remainder of the chapter covers additional high explosives including metal acetylides, triacteone triperoxide, nitrogen trichloride and triiodide, and azides.
Guncotton and smokeless powders are described in Chapter 4. Both are prepared by nitrating cellulose with nitric and sulfuric acids and are improvements over the use of black powder in firearms and artillery. It took some time before explosive uses were discovered. Nitroglycerine is covered in Chapter 5. Alfred Nobel developed dynamite, nitroglycerine absorbed on an inert powder, to enable nitroglycerine to be used safely as a commercial explosive. The text of his 1866 US Patent is included which also details its use as an explosive in boreholes. He also developed ballistite, a gel of guncotton dissolved in nitroglycerine for use as a smokeless powder. However, properties and politics led to the use of British cordite instead.
Picric acid, 2,4,6-trinitrophenol, described in Chapter 6, was originally prepared by nitration of indigo. Almost a century later it was prepared by nitration of phenol. It is a secondary explosive, insensitive to shock and heat, but its metal salts are quite sensitive which produces problems when it’s used to fill artillery shells. On December 6, 1917, the SS Mont Blanc, filled with explosives (mostly picric acid) caught fire after a collision in Halifax harbor, exploded with great loss of life and property damage.
TNT, 2,4,6-trinitrotoluene, is described in Chapter 7. It’s more difficult to detonate so it’s used in armor-piercing shells where a delayed explosion is desirable. TNT melts at 80 °C so it can be cast, which makes filling shells easier. On page 80, a table of relative effectiveness of various explosives is shown, defined, and referred to throughout the book. Chapter 8 describes Tetryl, 2,4,6-trinitrophenylntiramine, which has since been supplanted by the chemically related RDX and HMX, some the most explosive compounds in use. PETN, pentaerythritol, is described in Chapter 9. It is 1.6 times more explosive than TNT It has a neutral oxygen balance (the less oxygen the better to make a high explosive). PETN is used in primacord, a fuse cord to initiate other explosives. Since it is an ester, like nitroglycerine, it is a vasodilator used to relieve angina. The infamous Shoe Bomber tried to use PETN to bring down an airplane in flight.
Chapter 10 covers RDX, also known as cyclonite, which is cyclotrimethylenetrinitramine. The text of the original patent is shown. It has a very high detonation velocity. Blended with a plasticizer, binder, and motor oil, RDX yields the moldable C-4. Blended with TNT and powdered aluminum, RDX is used in antisubmarine depth charges. HMX, a compound related to RDX (cyclotetramethylene tetranitramine) is covered in Chapter 11. It is more stable than RDX and has an even higher detonation velocity. Chapters 12 and 13 describe less common but very energetic compounds including HNIW/CL-20 and TATB (triaminonitrobenzene).
Chapter 14 discusses polymer bonded explosives. The advantages are lowered sensitivity and easier moldability. They are used in detonation of nuclear devices, detonation cord, and torpedo warheads. Testing and properties for determination of explosives are discussed in Chapter 15 and several comparison tables are included.
Chapter 16 discusses the need for less sensitive explosives as illustrated by documenting several accidental explosions. Compounds range from ammonium picrate, nitroguanidine (also used as an insecticide), through several more exotic compounds with cage structures. There is a need for limiting or directing the effect of explosive blasts. Various methods and ingredients for shaped charges are described in Chapter 17. Uses range from effective rock drilling and blasting through armor-piercing shells and in nuclear weapons.
Chapter 18 recapitulates much of the previous material in discussing explosives by chemical class and several newly covered compounds are included. Thermobaric explosives, mixtures of fuels and oxidizer (usually air) are described in Chapter 19. Eco-friendly explosives are described in Chapter 20. Pollution resulting from manufacture as well as use must be considered. Use in civilian applications is especially important in functions including blasting, and firearms. Minimizing the use of lead in any form is more beneficial, including use of copper-coated bullets or tungsten-based bullets (which unfortunately are more expensive). Military and civilian use of TNT will continue because it’s cheap although it has been described as a potential carcinogen. High-energy rocket fuels bring their own list of essential criteria (including pollution) and are discussed in Chapter 21.
Lest the reader come to think that the only uses of explosives are for the military (or civilian blasting), Chapter 22 discusses explosives in the home. The very interesting chemistry and history of phosphorus is discussed and answers questions like “how do safety matches work” and “what is in the paper roll caps used in cap guns”. Red phosphorus is quite stable but is easily converted to white phosphorus which is quite shock sensitive and self-ignites in air. Match manufacture is discussed in detail. Carbide cannons, party poppers, and toy rockets are also described.
The blend of the history of explosives and world history in general would probably be more of interest to a general audience. The chemistry, especially the structure/property relationships discussed and chemical energetics, makes this book a valuable supplementary resource for chemistry classes and pedagogy at advanced high school and college levels. Offered at a reasonable price, this book is a must read for many chemical educators.