dinitrogen

4

Nitration of a methoxybenzoic acid. 

The tricky party is that the reaction starts at 45 °C, it is highly exothermic, uses high excess of nitric acid and it should be kept at maximum 40 °C. So what happens? Instant overreaction. 

If this is not bad enough, the yield of the preferred nitro compound is only 10-15% and a LOT nitrous fumes forms during the reaction as seen on the pictures. 

Interesting part is that the gas bubbler contained some water and the formed dinitrogen trioxide is being dissolved in it forming a blue solution. N2O3 is the anhydride of the unstable nitrous acid (HNO2), and produces it when mixed into water. However when it is in high concentrations, it stays in N2O3 form for a while and could be observed, just as in this case. 

If a base is added, the corresponding salt of nitrous acid could be formed:

N2O3 + 2 NaOH → 2 NaNO2 + H2O

2

Distillation of an alkyl nitrite. 

Nitrites are not the best for health, especially volatile organic nitrites. Amyl nitrite and other alkyl nitrites are used in medicine for the treatment of heart diseases. They are potent vasodilators; they expand blood vessels, resulting in lowering of the blood pressure under seconds.

The distillate contains a lower deep blue layer and an upper yellowish thing. The yellow oil is the nitrite and the blue thing at the bottom is dinitrogen trioxide (N2O3). It was formed from the minor decomposition of the nitrite. N2O3 forms upon mixing equal parts of nitric oxide and nitrogen dioxide and cooling the mixture. 

Preparing a nitrating solution from 100% nitric acid and phosphorous pentoxide.

Just a few short notes: the 98-100% nitric acid is a quite strong oxidizer. If I would spill it on my gloves it would ignite it in no time. Same would happen if I would spill it on my labcoat.

From the reaction of pure nitric acid and phosphorous pentoxide, nitrogen pentoxide is generated what is also known as the anhydrous form of nitric acid: N2O5 + H2O = 2 HNO3.

The dinitrogen pentoxide is a highly reactive white powder, melting at 41 °C. When it contacts with water, even with the humidity of the air, it produces nitric acid what is quite corrosive (those fumes what are coming out from the beaker). However, it is a great reagent if you would like to prepare a nitrate ester of any compound what you can found on the shelf.

2

Preparing a nitrating solution from 100% nitric acid and phosphorous pentoxide. 

Just a few short notes: the 98-100% nitric acid (first pics) is a quite strong oxidizer. If I would spill it on my gloves it would ignite it in no time. Same would happen if I would spill it on my labcoat. 

On the second pics the prepared nitrating mixture is seen. It is a bit like honey, especially when it’s cold. The only difference that it releases toxic fumes (as seen) and if I would like to taste it it would cause very-very serious burns

From the reaction of pure nitric acid and phosphorous pentoxide, nitrogen pentoxide is generated what is also known as the anhydrous form of nitric acid: N2O5 + H2O = 2 HNO3.

The dinitrogen pentoxide is a highly reactive white powder, melting at 41 °C. When it contacts with water, even with the humidity of the air, it produces nitric acid what is quite corrosive. However, it is a great reagent if you would like to prepare a nitrate ester of any compound what you found on the schelf. 

Just for fun: the reason why not to fill fire extinguishers with nitrous oxide instead of carbon dioxide. 

We ignited a small amount (few cm3) of toluene on a piece of aluminium foil and blew nitrous oxide on it. The results were great, as seen on the picture. 

Since the nitrous oxide acts as an oxidizer (it is used in rockets also) it helps the toluene to burn really-really fast.