German Chemists Invent a Lifeline


The First World War was an unprecedented catastrophe that killed millions and set the continent of Europe on the path to further calamity two decades later. But it didn’t come out of nowhere. With the centennial of the outbreak of hostilities coming up in 2014, Erik Sass will be looking back at the lead-up to the war, when seemingly minor moments of friction accumulated until the situation was ready to explode. He'll be covering those events 100 years after they occurred. This is the 84th installment in the series.

September 9, 1913: Germany’s Lifeline, the Haber-Bosch Process

Saltpeter, the active ingredient in gunpowder, is actually a group of chemically similar compounds such as potassium nitrate and sodium nitrate, whose common component can be guessed from their names: nitrogen. Until the early 20th century these nitrate compounds, which are also key ingredients in fertilizer, could only be found in big amounts in natural deposits, the largest of which were found in South America. But on the eve of the Great War, German chemists discovered a way to synthesize nitrates artificially – a momentous achievement that allowed Germany to fight on for four long years after its overseas sources of nitrates were cut off by the British blockade.

At first glance it might seem easy to find nitrogen, since it is a very common element, making up just over 78% of the Earth’s atmosphere. But even though it’s in the air we breathe, atmospheric nitrogen is so stable when bonded to itself in a “diatomic” state (N2) that it just won’t react with other chemicals under ordinary conditions – in short, you can’t do anything with it because there’s no way to get it out of the air. And that was how it stayed until German scientists, armed with the resources of the world’s most advanced industrial state, applied themselves to the problem.

By the turn of the 20th century Germany was the undisputed world leader in the new chemical and pharmaceutical manufacturing industries, the legacy of Prussia’s early lead in industrial production of dyes. Not coincidentally, Germany also led Europe in electricity production, which fueled the new industries. These factors converged in 1909, when the German chemist Fritz Haber figured out how to “fix” atmospheric nitrogen using large amounts of energy under very high pressures.

By raising the pressure to around 200 atmospheres, boosting the temperature to 450 degrees Celsius, and using iron as a catalyst, Haber was able to trigger a reaction in which one molecule of atmospheric nitrogen (N2) split and recombined with three molecules of atmospheric hydrogen (3 H2) to form two molecules of ammonia (2 NH3). Then, using a separate process developed by Wilhelm Ostwald in 1902, the ammonia could be converted to nitric acid (HNO3), which can in turn be used to produce nitrate compounds.

Executives from BASF immediately grasped the huge potential of the discovery when Haber demonstrated the process for making ammonia them in 1909: aside from the whole munitions issue, the Haber process stood to revolutionize fertilizer manufacturing and make agriculture more productive. Playing for high stakes, BASF went all in, wagering its financial future on the invention.

Making a Lot of the Ammonia You Buy Better

After buying the formula from Haber, BASF turned to another chemist, Carl Bosch, to figure out how to begin producing ammonia from atmospheric nitrogen on an industrial scale. After four years of work (and a very substantial investment in facilities and equipment, including high-pressure, high-temperature blast furnaces) on September 9, 1913, a BASF plant in Oppau, Germany, began producing ammonia at the rate of several tons per day, increasing to 20 tons per day by the following year. During the war the German government frantically scaled up capacity to an awesome 500,000 tons of ammonia per year, although actual production was only about half this.

While the Haber-Bosch Process lengthened the Great War by enabling Germany to fight on, its benefits for humanity are undeniable. Currently it is estimated that about half the protein in our bodies is made up of nitrogen fixed using the Haber-Bosch Process, while one third of the planet’s population depends for most of its nutrition on food grown using artificial fertilizers produced with the process. Haber and Bosch both eventually received Nobel prizes for their work (Haber in 1918, Bosch in 1931).

Of course, even when intended for a good purpose, nitrates can be incredibly dangerous: on September 21, 1921 a giant explosion leveled a large part of the Oppau plant (pictured above, after the explosion), killing 600 people and leaving a massive crater on the site.

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