[Chemistry] Process using catalyst simple notes

1) Contact process = manufacture of sulphuric acid.

(i) Stage 1 : Combustion.

S + O2 --> SO2

or

2ZnS + 3O2 --> 2ZnO + 2SO2

Then, SO2 is dried and purified.

(ii) Stage 2 : 

Purified SO2 is passed over vanadium (V) oxide , at controlled optimum conditions.

optimum conditions: 

- pressure : 2-3 atm

- temperature : 450 - 500 °C

- catalyst : vanadium (V) oxide, V2O5

equation:

2SO2 + O2 --> 2SO3 

(iii) Stage 3:

SO3 is dissolved into concentrated H2SO4, forming oleum, H2S2O7

SO3 + H2SO4 --> H2S2O7

Then, oleum is diluted with water.

H2S2O7 + H2O --> 2H2SO4

2) Haber Process = manufacture of ammonia

(i) direct combination of Nitrogen and Hydrogen in a ratio 1:3

[N] obtained from fractional distillation of liquid air

[H] from cracking of petroleum / CH4 (natural gas) + H2O --> CO + 3H2 

(ii) optimum conditions:

- pressure : 200 - 500 atm

- temperature : 450 - 500 °C

- catalyst : iron fillings, Fe

(iii) it is cooled and condensed to become liquid ammonia, NH3.

3) Ostwald Process = manufacture of nitric acid

(i) 4NH3 + 5O2 --> 4NO + 6H2O

with optimal conditions:

- pressure : 4 - 10 atm

- temperature : 900°C

- catalyst : platinum, Pt

(ii) 2NO + O2 --> 2NO2

(iii) 3NO2 + H2O --> 2HNO3 + NO