I don’t know about you, but when I think of ammonia, it doesn’t conjure up fond memories—a wood fire, pluff mud, or an aged bourbon. Nope—it’s truck-stop bathrooms and litter boxes. So why, you may ask, am I devoting so much digital space to that noxious compound? One reason, and it’s not all about that eye-watering stench: ammonia is sort of the next great hope on the renewable energy horizon. So I want to talk about exactly what it is, uses for ammonia today, and what the future looks like, Mr. Clean notwithstanding.
Ammonia is one of those compounds that makes you think “natural” products aren’t all they’re cracked up to be. It’s basically a byproduct of rotting organic matter: decomposing plants and animal waste products—the genesis of the aromatic litter box.
Anyway, it turns out that ammonia was first mentioned in the Canterbury Tales sometime in the 13th century. If you’re rusty on your Chaucer, he mentions sal armonyak in the Yeoman’s Tale—and wasn’t spelling armagnac in olde Englysh. In the Middle Ages, ammonia salts (fermented urine, you’re welcome) were used for cleaning, disinfecting, and manipulating the color of the vegetable dyes used in weaving. Tanners also used ammonia in preparing hides. Think about the origin of those cleaning products next time you reach for the Lysol.
Joseph Priestley, Chemist Extraordinaire
Priestley is one of those guys who laid the foundations for a ton of modern science. But he doesn’t get the same PR as Benjamin Franklin and the kite. Priestley was an English chemist who discovered that oxygen does not dissolve in water (he also discovered oxygen itself, NBD), making the combustion process more robust. This was his theory of “dephlogisticated air”—that oxygen burned better than nitrogen.
Priestley discovered several other gases that are still relevant in the energy and clean tech industries: carbon monoxide, sulfur dioxide, nitrous oxide, hydrogen sulfide, and ammonia.
What’s more interesting than ammonia is that Priestley determined the inverse square relationship between electrical charges a good ten years before Coulomb’s law defined electrical charges in terms of force. But wait, there’s more. Priestley also discovered the carbon cycle (converting CO2 to oxygen via photosynthesis and the reverse of respiration in animals). Then, let’s not overlook the fact that he invented carbonated water, an idea he sold to Joseph Schweppes, and the rest is history.
Ammonia in Polite Society
Smelling salts, that mainstay of Victorian literature, are nothing but ammonia gas. The gas irritates nasal passages, so the fainting lady is revived by burning lungs.
I couldn’t believe this bit of trivia (because I would have thought elite athletes had better drugs than smelling salts to enhance performance), but British tennis pro Tim Henman used them to boost his performance at Wimbledon in 2002. He didn’t win.
Here’s another fun fact. The main source of nitrate used in making ammonia came from Chilean sea bird guano in the Atacama Desert. However, by the early 1900s, it was apparent that the industrial and commercial uses for ammonia far outstrip the organic production possibilities. So the Haber-Bosch process was developed in the early 1900s to meet the burgeoning need for ammonia.
Basically, hydrogen and nitrogen are combined with a metal catalyst at high heat and pressure to create ammonia. The problem here is that using that combustion-fueled heat is not exactly an eco-friendly operation—the formula also produces greenhouse gases. So recently, chemists have been working to find ways to eliminate the heat component with electrochemical technologies.
It’s a Chemical Jack of All Trades
So ammonia is part of lots of chemical reactions. When you put it with hydrogen chloride, you get ammonium chloride. Add nitric acid, and ammonium nitrate is the result. Sulfuric acid and ammonia make ammonium sulfate. Add ammonia to strong acids, and it forms stable ammonium salts. Ammonium salts from weak acids quickly decompose into acid and ammonia. Some metal ions interact with ammonia to build complex ions, or ammines. Finally, ammonia is necessary in the body for stuff like amino acid and nucleotide synthesis (metabolic processes). There are too many uses for ammonia to count.
Ammonia Is Everywhere
What’s ammonia used for besides smelling salts and Lysol? Well, if you’re into your yard, you’ve noticed how fertilizer bags have a label with apparently random numbers—10-5-5, for example. This is not an arithmetic class. It’s telling you that the composition is 10% nitrogen, then phosphorus and potassium. So a 10 lb bag is 10%, or a pound, of nitrogen. Pure nitrogen is a gas that doesn’t do much for the soil, but the Haber-Bosch process turns the gas into ammonia that the plants can absorb.
I won’t bore you with how ammonia is prevalent in cleaning products, but it works well because it dries before a surface can streak. Using ammonia to clean jewelry also dates back to the Middle Ages, when they used it on precious metals and stones. The silver plates probably reeked, but in those days, I would imagine that nobody noticed.
Industrial agriculture utilizes NH3 (science for ammonia) as a pressurized liquid in storage tanks attached to tractors that cost more than your house. The ammonia filters through tubes in knife and shank projectiles that inject the fertilizer into the ground, about 20 centimeters deep. At contact, the NH3 becomes a vapor gas that’s trapped in the soil for the plants to absorb.
You can pick up a version of that same liquid fertilizer in a handy spray bottle for your tomato plants; since it’s in water, that’s aqueous ammonia.
When you buy strawberries at the grocery store, they’ve probably had a hit of NH3 to prevent mold and mildew. It’s the same thing for other high-water content fruits and veggies—tomatoes, oranges, and cucumbers are the most likely to grow fungi in those refrigerated boxes.
Your backyard garden aside, ammonia features in 80% of the world’s commercial fertilizers. These commercial fertilizers do two things: they accelerate healthy plant growth and help preserve the nitrogen native to the soil. Food crops organically deplete the nitrogen in the soil, so NH3 and other nutrients keep the fields viable year after year. It’s a definite plus for sustainability, even in giant factory farms.
Uses for Ammonia in Textiles
Modern manufacturing couldn’t happen without that technology that started in the Middle Ages. The textile industry still depends on it for tanning hides for leather. Also, liquid ammonia boosts fabric dyes, especially for synthetic fibers. In all honesty, it’s a miracle treatment for cotton—it strengthens the fibers, helps them hold the shapes, makes them more resistant to abrasion, and keeps the dyes colorfast. You can thank ammonia processes for those no-iron dress shirts that have halved your dry cleaning bills.
Ammonia as a Bleach and Ingredient in Washing Agents
Have dried blood on clothes, a persistent stain, or maybe heavily soiled shoe soles? With ammonia, this type of dirt is not a problem anymore. All you have to do is soak the footwear or clothes in an ammonia solution. CAUTION! Do not soak them for too long – otherwise, you will damage the material! After soaking, clean the shoes and wash the clothes. The stains will disappear quickly without a trace.
Industrial Uses for Ammonia
There are really too many industrial uses for ammonia to go into here, but we can safely say that life wouldn’t be the same without it. Here are some technologies that use ammonia that might surprise you:
- Refrigerants for gas and HVAC equipment. It absorbs heat from the compressors.
- Water purification and wastewater treatment systems use ammonia to boost the efficacy of chlorine.
- In other industries—cold storage, rubber, paper, and food and beverage—ammonia is a source of nitrogen and acts as a stabilizer or neutralizer.
- Treatment, leather, rubber, paper, food, and beverage industries
- It helps in cold storage or refrigeration systems and in the production of pharmaceuticals. When used as refrigerant gas and in air-conditioning equipment, ammonia can absorb substantial amounts of heat from its surroundings.
- Manufacturers use ammonia in the printing and cosmetics industries.
- It also helps with fermentation.
Uses for Ammonia in the Weapons Industry…
What you learned in middle school about mixing ammonia and bleach was pretty much Bomb Building 101. Ammonia is super flammable at high temperatures and spontaneously ignites at temps above 1100° F, which is half the heat of your average pottery kiln. In WWI, the Germans couldn’t access the ammonia variant Chilean saltpeter used to make gunpowder and other explosives, so you could probably argue that repurposed Lysol won that war.
…And in Petroleum and Mining
In an unexpected synergy, petroleum refining creates ammonia—the heat mixes with nitrogen and hydrogen, and voila. Ammonia also counteracts the acid in crude oil and helps keep the rig equipment from corroding. Unfortunately, I don’t think they’ve figured out a way to capture this byproduct and recycle it into production, but there’s an idea for you technically creative types.
In mining, ammonia is a catalyst in extracting nickel, copper, and molybdenum from the ore. In 2019, Fortescue Metals Group (FMG) announced they were working on a metal membrane technology that would create fuel-cell quality hydrogen. Stay tuned for additional progress into uses for ammonia.