Nitric Acid Fed Half the World, Powered Apollo, and Cracked Dynamite Wide Open

Nitric acid is one of the most quietly important industrial chemicals on Earth. It is a fertilizer factory, a rocket-engine oxidizer, an explosives precursor, and a gold-dissolving reagent — all from the same colorless bottle on the same chemistry-supply pallet. This is the story of how one molecule fed half the world, got Apollo to the Moon, made Alfred Nobel rich enough to fund a Peace Prize, and turned up in a flask in Copenhagen at the worst moment of the twentieth century.

The Fertilizer Equation: how one molecule feeds 4 billion people

Plants need nitrogen. The atmosphere is 78% nitrogen gas, N₂ — and yet plants cannot use a single molecule of it. The triple bond between the two nitrogen atoms in N₂ is one of the strongest covalent bonds in nature; cracking it open requires either the high temperature of a lightning strike or the high pressure of an industrial reactor. For most of human history, nitrogen-fixing bacteria living in the roots of legumes did the cracking, and the rest of agriculture was rate-limited by how much of their nitrogen could be persuaded to circulate through the soil.

Then in 1909 Fritz Haber demonstrated that you could combine atmospheric nitrogen with hydrogen at 400°C and 200 atmospheres of pressure to make ammonia (NH₃) directly. Carl Bosch industrialized the process. By 1913 BASF was producing ammonia at scale. The Haber–Bosch process is now considered the single most important industrial process of the twentieth century: it removed the nitrogen ceiling from agriculture, and global crop yields tripled.

But ammonia by itself is a difficult fertilizer to handle. It is a gas at room temperature, highly soluble in water, alkaline, corrosive to the eyes and lungs, and a controlled material under DOT and DHS rules. To make it shippable, storable, and field-applicable at industrial scale, you turn it into a salt. And the easiest, cheapest, most water-soluble salt of ammonia happens to be the one you get when you combine it with nitric acid:

Ammonium nitrate. Roughly 80% of all nitric acid produced worldwide is consumed in that one reaction, and most of that ammonium nitrate goes directly into fertilizer pellets that end up on a corn field, a wheat field, or a soybean field somewhere on the planet. ~50% of the world’s food calories currently exists because synthetic nitrogen fertilizer exists, and most of that synthetic nitrogen is shipped to farms in the form of ammonium nitrate. Nitric acid is the molecule that closes the loop.

How is nitric acid manufactured? The Ostwald process explained

Wilhelm Ostwald patented the industrial route to nitric acid in 1902 — seven years before Haber’s ammonia work and a decade before Bosch made it work at scale. The two inventions click together like puzzle pieces. Haber-Bosch gives you ammonia; Ostwald converts that ammonia into nitric acid. Together they convert nitrogen from the air into nitrogen on a corn-field.

The Ostwald process is a three-step catalytic oxidation:

The first step is the interesting one. Ammonia mixed with air is passed over a platinum-rhodium gauze catalyst at about 900°C. The contact time is about 1 millisecond. Without the catalyst the ammonia would just burn to nitrogen and water. With the catalyst, the selectivity flips: nitric oxide forms instead of dinitrogen, and at >95% yield. It is one of the great pieces of industrial catalysis ever discovered.

The product of the absorption tower is roughly 65–68% nitric acid in water. To go higher (the 98%+ “fuming” concentrations) you have to break the azeotrope, typically with magnesium nitrate dehydration or sulfuric-acid drying. Most fertilizer-grade and industrial-grade nitric acid stops at the 65–70% level — which is exactly the strength of the bottles on our pallet today.

Why 80% of all nitric acid becomes ammonium nitrate

You could in principle make nitrogen fertilizer in many ways. Urea (CO(NH₂)₂) is the largest single nitrogen fertilizer by tonnage worldwide. Anhydrous ammonia is injected directly into US corn-belt soils at scale. Calcium ammonium nitrate (CAN), urea-ammonium nitrate (UAN), and ammonium sulfate all see real volume. But ammonium nitrate has properties no competitor matches:

The same properties that make ammonium nitrate useful as a fertilizer also make it useful as an oxidizer in mining explosives (ANFO, ammonium-nitrate-fuel-oil) and gave it its other historical fame as the active ingredient in fertilizer-bomb tragedies (Oklahoma City 1995, Beirut Port 2020). Most countries now regulate retail ammonium-nitrate sales heavily; in the US it is governed by the Ammonium Nitrate Security Program under DHS. That regulation is part of why the chemistry feels invisible: the same nitrogen atoms feeding your dinner plate are tracked by Homeland Security on the way to the warehouse.

Apollo’s quiet oxidizer: how a nitric acid bottle got the lunar module home

Every NASA Apollo mission depended on engines that could be fired with absolute reliability after a week in cislunar space. There is no second chance at lunar-orbit insertion, and there is no second chance at trans-Earth injection. The propellant has to ignite the instant the valves open.

The class of propellant that does this is called hypergolic: the fuel and oxidizer ignite on contact without a spark plug or igniter. No ignition system means nothing to break. For Apollo’s Service Module engine (the AJ10-137, designed by Aerojet) the fuel was Aerozine-50 (a 50/50 mix of unsymmetrical dimethylhydrazine and hydrazine), and the oxidizer was nitrogen tetroxide (N₂O₄) — a compound that lives in equilibrium with two NO₂ molecules and that is produced industrially from nitric acid by a controlled dehydration step.

The Titan II ICBM, which was repurposed as the Gemini launch vehicle, used a closely related propellant called Aerozine-50 / IRFNA. The acronym is worth decoding: Inhibited Red Fuming Nitric Acid — concentrated nitric acid (typically 83% HNO₃ + 14% N₂O₄ + 2% H₂O + 0.6% HF as a corrosion inhibitor). The HF was the inhibitor that gave the “I” in IRFNA; without it the acid would eat through the propellant tanks during the rocket’s long missile-silo standby life. With the HF, IRFNA could sit in a Titan II silo for years and still ignite on contact when the valves opened.

The chemistry is the same chemistry that sits in our 70% bottle today. The 70% concentration we ship is the working concentration for laboratory and industrial use, not propellant grade — the rocket version was a much narrower spec and is no longer manufactured for civilian use. But the molecule is identical. Every time you pour a beaker of HNO₃ you are handling a small piece of the same compound that sent Neil Armstrong to the lunar surface and brought him home.

From glycerin to dynamite: Alfred Nobel’s bottle that started the Nobel Prize

In 1846 the Italian chemist Ascanio Sobrero, working in Turin, slowly added glycerin to a chilled mixture of concentrated nitric and sulfuric acid. He recovered an oily, slightly sweet liquid — nitroglycerin — that he then promptly demonstrated would detonate if struck. Sobrero was so disturbed by his discovery that he buried the notebooks and spent the rest of his life warning against any practical use of the compound.

Twenty years later a Swedish industrialist named Alfred Nobel was running a small chemical works in Stockholm. His younger brother Emil died in a nitroglycerin explosion at the family laboratory in 1864. Most people would have stopped. Nobel doubled down and looked for a way to stabilize the compound so that it could be shipped and handled safely on construction sites.

His insight, in 1867, was that nitroglycerin absorbed into a porous mineral called kieselguhr (diatomaceous earth) became a stable, shapeable putty that could be cut, shipped, drilled into rock, and detonated reliably with a percussion cap. He patented the product as “dynamite” — from the Greek dynamis, “power.” Within a decade dynamite was building railroads, harbors, and tunnels on six continents. Nobel became one of the richest men in Europe.

When Alfred Nobel died in 1896, his will directed that the bulk of his fortune be used to establish prizes in physics, chemistry, medicine, literature, and peace. The endowment fund the prizes still come from in 2025 traces directly to the dynamite he sold — which means it traces directly to the nitric acid he used to make it. The chemistry-supply pallet in our warehouse is two steps removed from the Nobel Peace Prize.

Aqua regia and the Nobel medal: Niels Bohr’s WWII escape

The 8th-century Persian alchemist Jābir ibn Hayyān recorded a mixture of nitric and hydrochloric acids that he called aqua regia — royal water — because it was the only solvent known that could dissolve gold and platinum, the “royal” metals. Twelve centuries later, the chemistry of aqua regia is still doing what Jābir noticed.

Mix 1 part concentrated nitric acid with 3 parts concentrated hydrochloric acid by volume and the two acids react to produce nitrosyl chloride and chlorine gas:

The nitric acid oxidizes the gold, ripping electrons off the metal surface; the chloride ions immediately bond to the gold cations to form the soluble [AuCl₄]⁻ ion. Neither acid can do this alone — the gold is too noble for HCl to attack, and the gold cations formed by HNO₃ alone would immediately reduce back to metal. The combination breaks the stalemate.

In April 1940 the German army occupied Denmark. The physicist Niels Bohr was at his institute in Copenhagen, holding the gold Nobel medals of two German physicists (Max von Laue and James Franck) who had smuggled them out of Nazi Germany for safekeeping. Exporting Nobel-gold from Germany was punishable by death; possession of it in occupied Denmark was nearly as risky.

Bohr’s colleague George de Hevesy — a Hungarian chemist working in the same building — suggested a chemistry solution. They dissolved both medals in aqua regia. Bohr left the unlabeled bottle of orange-brown solution on a laboratory shelf and walked out of the building with the Nazis searching room by room. The bottle sat untouched for the rest of the war. In 1950 de Hevesy returned to Copenhagen, precipitated the gold out of solution, and shipped it to the Royal Swedish Academy, who recast the medals and returned them to Laue and Franck.

The grades of nitric acid at Alliance

Alliance Chemical stocks nitric acid at seven concentration points across three certified grades. The chemistry is the same molecule (HNO₃) at every concentration; the difference is what you certify it against.

Technical Grade meets internal Alliance Chemical specifications and is the right choice for industrial applications where the certificate of analysis confirms identity and approximate purity. ACS Grade meets American Chemical Society reagent specifications — tested against the canonical ACS test methods for heavy metals, residue on ignition, color, and chloride. ACS Reagent Grade in the 55-gallon drum format ships with a lot-traceable certificate against the same ACS methods, scaled for production use.

What grade of nitric acid should you buy?

Buyer’s rule of thumb: match the grade to the downstream specification, not to the upstream price. For most industrial cleaning, passivation, and pH-adjustment work, Technical Grade at the right concentration is correct and cost-effective. ACS Grade is justified when your downstream process specifies ACS by name, when trace metals would interfere with analytical work, or when you need lot-traceability against the canonical reagent-grade test methods.

Never mix: 4 contraindications for nitric acid

Nitric acid is a strong acid and a strong oxidizer. The two properties give it twice the contraindication list of an ordinary mineral acid. Four combinations to avoid:

Storage rule: keep nitric acid in its labeled corrosives cabinet, away from organic solvents and reducing agents, on a secondary containment tray, with a dedicated spill kit (soda ash + acid-resistant absorbent pad) within arm’s reach.