Chemistry and the Great War

In April 1915, American newspapers reported that the USA faced a “dye famine”, with only two months’ supply left. This was not a minor inconvenience but threatened the livelihoods of 2 million workers as dyes were essential in the textile, paint, paper, and printing industries, among others. What had happened?

You may recall the Bunsen burner, the Liebig1 condenser, and the Haber2 process from your school days, named after just three of the many world-leading chemists underpinning the German chemical industry, the largest in the world by the outbreak of the Great War. Developing in the 19th century, this industry made steel, dyestuffs, explosives and medicines. In 1913, Germany produced getting on for 90% of the world’s artificial dyestuffs or raw materials for these, mostly produced from coal tar. They also dominated in other areas, such as production of potash fertiliser.

After the war started, Germany could no longer export dyes due to a naval blockade: hence the “dye famine.” In any case, the Central Powers needed these chemicals themselves for the war effort but so did the Allied Powers and the latter had to rapidly scale up their chemical industries. By the end of the war, chemicals production had expanded greatly in many countries, setting the scene for the development of an extraordinarily effective and lucrative industry that has dominated the world economy ever since.

Why were chemicals needed? In short, to make explosives, fertilisers, medicines and antiseptics, dyes, and poison gases.

The warring nations needed raw materials for dyestuffs, explosives and fertilisers. Much came from coal tar with which all were well supplied but they needed sources of “fixed” nitrogen for explosives and fertilisers. A major source of suitable nitrogen compounds was Chile saltpetre (sodium nitrate) but this was soon denied to Germany by naval blockades. Britain and its allies were also partly cut off by German naval activity and were faced with a similar though less acute shortages.

Explosives WW1 was a war of shells, projectiles packed with high explosive and fired by guns. Just one type of gun, the standard 18-pounder British field gun fired 86 million shells, two for every three seconds of the war.

Each shell comprised a steel casing containing lyddite (picric acid) or amatol (TNT and ammonium nitrate), with a mercury fulminate fuse as detonator. A bag of cordite propellant was placed behind the shell in a cartridge case.

Most explosives rely on the rapid oxidation of a compound containing carbon, hydrogen and, usually, nitrogen. Such compounds are less stable than their oxidation products, water and carbon monoxide; also, nitrogen compounds are less stable than the element nitrogen. This means that the reaction is very exothermic – it releases a lot of heat energy. Moreover, the products are gases, carbon monoxide, steam and nitrogen. Since these take up thousands of times more space than the explosive chemicals, there is an enormous increase of pressure, in short a hot blast.

Just burning the chemicals would release the same energy but much more slowly, as the oxygen would have to diffuse through the air to the fire. Explosive chemicals therefore either have to contain a lot of oxygen or be mixed with an oxidant, a chemical which releases the oxygen when and where required. In gunpowder, sulfur and carbon burn rapidly in the presence of potassium nitrate (nitre), exploding if in a confined space. More modern high explosives (HE), such as picric acid, nitroglycerine or trinitrotoluene (TNT: C7H5N3O6), contain substantial amounts of oxygen and are their own oxidants.

The propellant (a low explosive) pushes the shell at great speed out of the gun barrel. The fuse detonates the HE which blows the case apart. HE produces a supersonic blast or pressure wave which causes great damage to the surroundings. Shells can also contain smoke-producing chemicals, fire-producing substances such as phosphorus (incendiary), metal objects (shrapnel), bright-burning chemicals (flares), or poison gases.

The chemicals needed came from a variety of sources: coal tar for phenol and toluene; saltpetre for nitric acid; cotton for guncotton; glycerine from animal and plant fats and oils for nitroglycerine; acetone for cordite from distillation of wood. All were in shortage to some extent for both sides.

Response to shortages The Central Powers expected the war to be won quickly and only had sufficient supplies to last until 1916. In particular, sources of “fixed” nitrogen, needed for both explosives and fertilisers, and of glycerine, needed mainly for explosives, were inadequate. Fritz Haber described the choice as whether “to starve or to shoot.” Haber had developed a solution to the nitrogen problem with the Haber process (remember your chemistry lessons!) which combines nitrogen from the air with hydrogen to make ammonia. There was no shortage of air or hydrogen! The ammonia was used to make fertilisers or converted to nitric acid (for explosives) by the Ostwald process.

Thus Haber and Ostwald allowed Germany to carry on making enough munitions for another two years but, the choice between “guns or butter” having been made in favour of guns, severe food shortages caused malnutrition and loss of morale.3 Britain could make nitric acid from Chile saltpetre and did not suffer so much from these problems.

Munitions factories The Allies expected a swift conclusion, too, and stockpiles of munitions were rapidly depleted, resulting in the “shell crisis of 1915.” This caused the failure of a major British offensive. The response was to set up over 200 munitions factories, staffed largely by women filling cartridges, shells and bombs. The “munitionettes” ran many health risks from hazardous chemicals, in addition to the risk of fire and explosion.

Acetylene Welding 1917 Christopher R W Nevinson 1889-1946 http://www.tate.org.uk/art/work/P03047
Acetylene Welding 1917 Christopher R W Nevinson 1889-1946 http://www.tate.org.uk/art/work/P03047

There were five particularly serious explosions. In 1916, at the Explosives Loading Company, near Faversham, Kent, 15 tons of TNT and 150 tons of ammonium nitrate exploded. “The Great Explosion” killed 116, left a 40-yard crater, shattered windows in Southend 20 miles away across the Thames estuary, and was heard in France. In 1917, in densely-populated Silvertown, London, a fire set off 50 tons of TNT, causing an explosion heard 100 miles away, killing 73 and injuring 400. The greatest loss of life was at the National Shell Filling Factory in Chilwell, Nottingham. In 1918, 8 tons of TNT exploded, killing 134 and injuring 250. Thirty-five “Barnbow lasses” were killed in Leeds in 1916; 38 were killed at Low Moor, near Bradford, also in 1916; and many others died in smaller explosions.

The “acetone crisis” Acetone, an organic solvent, was essential for making cordite (without which shells and bullets could not go anywhere). British acetone was either imported from the USA or made by distilling wood, neither of which was sufficient. The chemist Chaim Weizmann5 successfully developed a fermentation process to make acetone from maize. Schoolchildren were enlisted to collect conkers (horse chestnuts) as it was found that these could be used as well. Over half the UK’s cordite was produced at the munitions plant at Gretna.4 Here, the munitionettes would knead nitroglycerine and guncotton with acetone into what Conan Doyle termed “devil’s porridge.”

Agricultural fertilisers Potash was an important chemical fertiliser whose use was encouraged by Liebig. At the start of the war, world supplies mostly came from potash mines in Germany, while nitrogenous fertilisers came largely from Chile as saltpetre. British chemical fertilisers were not in short supply but the US was greatly affected by the loss of potash from Germany. The “potash crisis” increased prices ten-fold and led to ingenious schemes to obtain potassium compounds (from rocks, wastes from iron blast furnaces, seaweed, banana stalks, salt lakes, cement kilns). This new potash industry collapsed after the war, leaving several ghost towns.

Glycerine and whaling This oily substance was needed to make nitroglycerine (for cordite). Obtained from plant and animal oils and fats, it rapidly ran short. This led to a massive increase in whaling as blubber was a rich source of glycerine. Whale oil was also used to rub into troops’ feet to combat “trench foot” which could lead to temporary or permanent inability to fight.

Whaling was then dominated by Britain and Norway. Neutral Norway sold its whale oil to both sides but was eventually persuaded by strong-arm tactics to sell most of its oil to Britain at a bargain price.

The Central powers used sugar fermentation to restore self-sufficiency in glycerine (the other product, alcohol, did not go unused!). Some 80,000 whales perished to satisfy war-time demands. I’ll discuss the uses of chemicals to kill or cure in WW1 in another article.

1 Justus von Liebig invented the meat extract later named Oxo. He was also known as “father of the fertiliser industry.”

2 Fritz Haber, “father of industrial nitrogen fixation.” The tragedy of Haber will be covered in a future article.

3 Food shortages were also important in the outbreak of the February revolution in Russia 1917.

4 HM Factory Gretna stretched for 12 miles along the Scottish-English border in four sites, with a dedicated coal-fired power station and 125 miles of narrow-gauge railway. Two townships housed the mainly female workforce, with kitchens, bakeries and laundries. Their “moral” welfare and factory discipline was looked after by a women’s police force. Local pubs and breweries were nationalised to control alcohol consumption.

5 Russian-born Chaim Weizmann, “father of industrial fermentation,” emigrated to Britain to help advance the Zionist cause. He discussed Zionist aspirations with Arthur Balfour, gaining his support for a Jewish homeland. He became the first president of Israel.

Note: much credit for this article goes to Michael Freemantle’s books Gas! Gas! Quick, boys! (2012) and the more extensive The Chemists’ War: 1914-1918 (2015, Royal Society of Chemistry; ISBN 978-1-84973-989-4).

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