Before we get to how they make nitrous oxide, we first got to learn what is Nitrous Oxide? Nitrous oxide, commonly known as laughing gas, nitrous, N2O, or nos, or nangs is a chemical compound, an oxide of nitrogen with the formula N2O. At room temperature or the temperature that adapted to its surroundings, it is a colorless non-flammable gas, that gives off a slight metallic scent and taste. At elevated temperatures or above normal oral temperature, nitrous oxide is a powerful oxidizer similar to molecular oxygen. Nitrous oxide has significant medical uses, more so present in surgery and dentistry, for its anesthetic and pain numbing effects. Better known by the masses as “laughing gas”, it received this name due to the euphoric effects a person experiences after inhaling it, with this property that has led to its use as a anesthetic. You can readily buy laughing gas but only for culinary purposes.
It is on the World Health Organization’s List of Essential Medicines, the safest and most effective medicines needed in a health system. Though it became popular as an anesthetic, nitrous oxide has so many other uses. It increases internal combustion engine power, serves as an oxidizer in experiments including chemicals and rockets, and it also acts as a propellant for foods including cooking spray and whipped cream, and has multiple uses in medicine showing that it has its flexibility in uses as a chemical compound.
After learning what is Nitrous Oxide, How does someone produce said gas? The basic and safe method to make nitrous oxide at home or in a small lab was discovered by a chemist named Humphry Davy. Davy discovered that through heating ammonium nitrate, it decomposes into nitrous oxide and water vapor:
NH4NO3 (s) → 2 H2O (g) + N2O (g)
While simple, it’s crucial to gently adjust the heat of ammonium nitrate between 170 °C to 240 °C (338 °F to 464 °F). Exceeding the maximum temperature leads to rapid decomposition and the glass container to shatter due to reaching its breaking point. Use small amounts of ammonium nitrate then control the temperature with a thermometer just to be safe.
1. Place a small amount of ammonium nitrate in a test tube. Cap the test tube with a one-hole stopped. Insert plastic or glass tubing into the hole and run it into a hot water bath. The water needs to be hot because nitrous oxide dissolves in cold water, reducing the amount collected. Collect the bubbles in an inverted jar. This setup for collecting gases is called a pneumatic trough. It condenses water produced by the reaction and removes impurities, like smoke.
2. Once you’ve set up the equipment, slowly heat the ammonium nitrate. You can do this over a flame or burner. Apply heat so that it does not exceed the maximum temperature and so it produces gas bubbles at the rate of one to two bubbles per second.
3. Stop heating the ammonium nitrate before all of it has decomposed. This helps prevent overheating. Turn off the heat and disconnect the tubing from the collection jar so that water won’t flow up into it. Cover the container before turning it upright, so you won’t lose the gas. You can seal the container while it is inverted or simply cover it with a flat sheet of plastic or glass before turning it over. The gas in the container is nitrous oxide, plus smaller amounts of other nitrogen oxides, such as nitric oxide and nitrogen monoxide. Exposure to air oxidizes the nitric oxide to form nitrous oxide.
This procedure is commonly used for commercial preparation of nitrous oxide, with acid and base treatments to further purify the gas.
In 1772, another method for making nitrous oxide was discovered by Joseph Priestley and he became the first person to synthesize nitrous oxide. Priestly collected the gas produced by sprinkling nitric acid over iron filings. While an effective method, this method is better attempted in a lab by scientists because nitric acid should be used under a fume hood, with proper gear to avoid accidents. Another method to make nitrous oxide in the home or lab is to heat a mixture of sodium nitrate and ammonium sulfate. Again, collect the gas using a pneumatic trough. Heating this mixture is even safer than decomposing ammonium nitrate.
2 NaNO3 + (NH4)2SO4 → Na2SO4 + 2 N2O+ 4 H2O
The chemical reaction between urea, nitric acid, and sulfuric acid also produces nitrous oxide.
2 (NH2)2CO + 2 HNO3+ H2SO4 → 2 N2O + 2 CO2 + (NH4)2SO4 + 2H2O
Here are tips to prepare nitrous oxide safely:
– Never exceed the temperature when heating ammonium nitrate over 240 °C or 464 °F.
– Turn of the heating apparatus before the last bit of ammonium nitrate has decomposed.
– Use the highest purity ammonium nitrate available for the safest method. Pure ammonium nitrate is more stable than ammonium nitrate with impurities.
– Perform the project in a lab or in a well-ventilated area if at home. Overexposure can be fatal.
Due to the dangers difficulty involved in making nitrous oxide yourself you will most likely want to just buy nitrous oxide from an online seller and have it delivered to you.
