Nitrogen Production

Nitrogen Production

In laboratory nitrogen may be prepared by decomposition of Ammonium nitrate:

NH4NO2 => N2^ + H2O

It is an exothermic reaction which releases 80 kcal or 335 J of thermal energy, so cooling of the reservoir is required, however Ammonium nitrate has to be heated to initialize the reaction.

Practically in this case saturated solution of sodium nitrite is dripped into heated saturated ammonium sulphate solution. This reaction yields ammonium nitrite which is instantly decomposed. Disengaged gas is contaminated by ammonia, nitrogen oxide (I), and O, and is purified on the next stage by passing it through diluted sulfuric acid, ferrous sulphate (II), and glowing copper. After that nitrogen is dried.

Another laboratory method of preparation is heating of mixture of potassium dichromate and ammonium sulfate with mass ratio 2:1. The reaction equations are:

K2Cr2O7 + (NH4)2SO4 = (NH4)2Cr2O7 + K2SO4

(NH4)2Cr2O7 =>(t) Cr2O3 + N2^ + 4H2O

Most pure nitrogen may be produced by decomposition of metals azides:

2NaN3 =>(t) 2Na + 3N2^

So-called air or atmosphere nitrogen, which is the mixture of nitrogen with Noble Gass, may be yielded by the reaction between air and glowing coke:

O2+ 4N2 + 2C => 2CO + 4N2

The product of this reaction is so-called generator gas or air-blast gas which is used as a fuel and as a feedstock for chemical synthesis. The nitrogen may be separated, if necessary, by carbon monoxide capturing.

The industrial way of obtaining molecular nitrogen is the fractional distillation oh liquid air. This is also a suitable way to produce atmosphere nitrogen.

The laboratory way of preparation is passing ammonia over copper oxide (II) at temperature approximately 700°C:

2NH3 + 3CuO => N2^ + 3H2O + 3Cu

Ammonia may be obtained by heating its saturated solution. Before applying nitrogen is purified by passing over copper and its oxide at the same temperature approximately 700°C, and then dried by concentrated sulfuric acid and dry alkali. This is a slow process, but it worth it as high grade purity gas is evolved.