Making of ammonia from its elements

*Haber Process

*Uses of AmmoniaFertilisers, fibers, plastics, nitric acid (explosives), household cleaners, detergents

*Chemical monitoring

N2 and H2 Ammonia

*EquilibriumTo produce ammonia:1. Increase pressure (it will tend to decrease the number of moles of

gas)2. Decrease temperature (it will tend to increase temperature)

* Increasing pressure increases the frequency of successful collisions

*Compromise:Construction of strong pipes to maintain high pressures is not economical. Pressure needs to be lessened

*Pressure

* Lower temperature produces the highest yield of ammonia (~90%) but at a very slow rate (months!) as there is insufficient kinetic energy for a collision

* Compromise:Use slightly higher temperatures to yield smaller amounts quickly.

*Temperature

* Catalysts speed the forward and reverse reaction.

* It does not change the position of equilibrium

* Compromise:A catalyst makes it possible to use lower temperatures

*Catalyst

*Magnetite Catalyst (Fe3O4)

*Conditions:1. Increase reactants (but

must maintain 1:3 ratio)2. Pressure: 25 MPa (25,000

Pa)3. Temperature: 400oC 4. Magnetite Catalyst5. Product is removed

Yield of ammonia: ~15–20% per cycle. After 5–6 cycles about 98% of thereactants are converted to ammonia.

*Sources of H2 and N2

*Why Monitor?Efficiency and safety