Food-grade nitrous oxide has many purposes, from making whipped cream to fuel for rocket engines. It’s also used to enhance the quality of the final product, such as making ice cream creamier or chocolate softer.
¿Qué es el óxido nitroso?
Also known as laughing gas, nitrous, or nitrous oxide is a chemical compound that is non-flammable, sweet-smelling, and colorless. It’s widely used in surgery and dentistry because of its pain-reducing properties and anesthetic effects.
Method 1: Decomposition of Ammonium Nitrate
The safest and simplest method to produce food-grade nitrous oxide is through the decomposition of ammonium nitrate. When you gently heat ammonium nitrate, it breaks down into nitrous oxide and water.
NH4NO3 → 2 H2O + N2O
I. Put ammonium nitrate in a sizable test tube.
The goal is to use as little ammonium nitrate as possible to avoid the fast release of gases.
ii. Capping and tubing
Use a one-hole rubber stopper to cap the test tube and insert a glass or plastic tubing into the one-hole stopper.
The tube should run into an already set up hot water bath. To do this, use a pneumatic trough and lead the tube from the test tube or any other ammonium nitrate container through the water and into an inverted jar. A pneumatic trough is useful for this process because it gets rid of water, smoke, and other impurities from the reaction.
iii. Gently heat ammonium nitrate
Once everything is ready, heat small amounts of ammonium nitrate gently because extreme temperatures can lead to an explosion. To control the temperatures, use a heat source that has a thermostat or a thermometer to record.
You can use a burner or any other flame but always ensure the heat isn’t higher than the maximum temperature. You can also check to ensure that the heat produces about one or two gas bubbles per second, usually the optimal rate.
iv. Discontinues heating
While cooling the hot gas, discontinue heating before all ammonium nitrate decomposes to prevent overheating. Typically, this will happen when you notice your collecting jar is almost full of gas.
After turning off the heat source, immediately disconnect the plastic or glass tubing for the jar to prevent water from flowing up into the collecting jar.
v. Turn the collecting jar upright
The last step is to cover the collecting jar tightly before turning it upright to prevent the collected gas from escaping. To do this, use a flat sheet of glass or plastic or even seal the jar before turning it.
It’s worth noting that the gas you’ll collect will be a mixture of nitrous oxide and some amounts of nitrogen oxide, especially nitrogen monoxide and nitric oxide. When exposed to air, the nitric oxide turns into nitrous oxide, which all make up food-grade nitrous oxide.
Method 2: Decomposition of Ammonium Sulfate and Sodium Nitrate
You can make food-grade nitrous oxide in the laboratory by heating ammonium sulfate and sodium nitrate.
2 NaNO3 + (NH4)2SO4 → Na2SO4 + 2 N2O + 4 H2O
Method 3: Mixing Sulfuric Acid, Nitric Acid And Urea
Mixing sulfuric acid, nitric acid, and urea can also produce food-grade nitrous oxide in the laboratory.
2 (NH2)2CO + 2 HNO3 + H2SO4 → 2 N2O + 2 CO2 + (NH4)2SO4 + 2 H2O
Method 4: Reaction Between Sodium Nitrite and Hydroxylammonium chloride
Adding sodium nitrite to a solution of hydroxylammonium chloride forms oxides of nitrogen.
NH3OHCl + NaNO2 → N2O + NaCl + 2 H2O
Method 5: Decomposition of Hyponitrous acid
Heating hyponitrous acid at 25 °C breaks it down into water and nitrous oxide.
H2N2O2→ H2O + N2O
Safety Precautions When making Food Grade Nitrous Oxide
When performing chemical procedures in a lab or at home, there are many risks involved. When making food-grade nitrous oxide, you’ll be handling gases, and there might be an explosion, poisoning, or even burns caused by contact with flames.
It’s essential to assess the risks involved in the procedure and take the necessary precautions. Here are some safety tips to use when making food-grade nitrous oxide at home or in the lab:
- Wear protective gear: When handling corrosive or hazardous chemicals, you should always use protective equipment. For instance, ammonium nitrate can cause eye and skin irritation, so you should always wear approved eye and face protection as well as use gloves. If ammonium nitrate comes into contact with your eyes, ensure you rinse your eyes thoroughly with water if the irritation persists even after rinsing for several minutes and seek medical attention.
- Store food away: Don’t eat in a laboratory or store food or beverages near your working area to prevent food poisoning. If you happen to swallow small amounts of contaminated substances, rinse your mouth thoroughly with water. However, in case you consume large quantities, seek medical assistance immediately.
- Don’t work alone: You must perform a chemical procedure under supervision or with the help of someone. Just ensure you are not alone and there is someone in the immediate vicinity who can help you in case of an emergency. For instance, when there is a fire outbreak, an explosion, or in cases where you suffocate and need assistance.
- Work in a ventilated room: Even if nitrous oxide is a safe gas, it’s always advisable to perform the procedure in a well-ventilated room. That’s because if there is overexposure, usually through inhalation, you are likely to suffer asphyxiation. Other effects of inhaling the gas include excessive sweating, headaches, shivering, or nausea.
- Use moderate temperature: When preparing food-grade nitrous oxide from ammonium nitrate, you shouldn’t overheat it. Ensure to use a heat source that has a thermostat or a thermometer to measure temperature. It’s advisable to maintain temperatures between 170 °C to 240 °C because high temperatures might cause the ammonium nitrate to detonate and break the glassware.
Extra tip: Safety procedure practices start from using quality materials. When decomposing ammonium nitrate, it’s vital to use pure ammonium nitrate. The purer ammonium nitrate is, the safer the procedure.