NaOH + CH3NO2
It is said, that when sodium hydroxide and nitromethane are added to each other, that a very exothermic reaction occurs, and that the mix may even inflame.
It is known in literature, that nitromethane can react with a strong base to form so-called nitronate salts. This synthesis, however, requires very carefully chosen reaction conditions and anhydrous conditions. In this experiment, no nitronate is formed, but some brown crap. Nitronate salts are white.
This experiment was performed, just for the fun of seeing the violent reaction. OTC products were used, nitromethane, used for fuel boosting and sodium hydroxide drain cleaner. The experiment was carried out in a small 25 ml pyrex beaker.
In the small beaker, approximately 5 ml nitromethane was poured, and to this appr. 1/3 of the volume of solid NaOH was added.
The result of this experiment is a lot of frothing and bubbling and a strong rise of temperature. The bubbling is due to boiling of the nitromethane. The reaction is quite strong. In the course of a minute or so, the color changes from pure white to dark brown, while bubbling vigorously. The following 8 pictures are from a time frame of less than 1 minute. At the top-left, just after adding the solid NaOH, at the bottom right appr. 1 minute later.
I hoped to get the famous flame in this reaction, but no success with that. The experiment was repeated 3 times, with varying amounts of nitromethane (10 ml, 5 ml) and sodium hydroxide (just a thin layer, a lot, such that the entire volume of liquid is filled up). The result, however, was the same in all experiments, no flame, no fire.
A video of this experiment can be downloaded: NaOH_CH3NO2.avi. Download size is just over 2.5 MByte.
Use of powdered sodium oxide instead of prills of sodium hydroxide
A similar experiment was performed with Na2O instead of NaOH. The Na2O is a powdered white chemical. The sample of Na2O used in this experiment is quite old, so it probably contains quite some NaOH and Na2CO3 as well. The main difference with the NaOH is that this chemical is powdered, while the NaOH is made of little prills.
When a single drop of nitromethane is poured on a little pile of this old Na2O then it immediately inflames and sometimes even explodes! The pictures below show the result of two such experiments
A movie, showing the fire and explosions can be downloaded here: Na2O_CH3NO2.avi. Download size is appr. 6.5 MByte. The sound of the movie is not very good. There was a lot of wind when the experiment was done and this results in a lot of noise in the movie.
Pouring the nitromethane on the sodium oxide was not done directly by hand, but a device, made of a long metal stick and a clamp for holding a test tube was used. This allows pouring the nitromethane with the hands at a distance of well over 1.5 meters. A picture of this device is shown here. It really is necessary to be at a safe distance when the nitromethane comes in contact with the sodium oxide. With this device that can be achieved.
