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Flashcards in Manufacturing Of Products Deck (11):
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Manufacturing of sodium hydroxide

Manufactured by the electrolysis of a concentrated solution of sodium chloride. Hydrogen is a by product

+anode: chlorine loses electrons, chlorine molecules formed

-cathode: water molecules gain electrons, hydroxide ions and hydrogen molecules formed

1

Diaphragm

Necessary to keep apart sodium hydroxide and chlorine so they don't make bleach

2

Uses of sodium hydroxide

Manufacture of
Bleach, paper, soap, detergents

3

Uses of chlorine

Sterilising water supplies
Manufacture of:
Bleach, hydrochloride acid, PVC

4

Stages of sulphuric acid manufacture

Sulfur dioxide -> burning sulfur in air
Sulfur trioxide -> sulfur dioxide reacted with oxygen
Oleum -> sulfur trioxide absorbed into concentrated sulfuric acid
Sulfuric acid -> Oleum carefully diluted


5

Manufacturing sulfuric acid exras

Vanadium oxide catalyst
Reversible reaction
Position of equilibrium
Forward action is exothermic
Yield of sulfur trioxide high at low temperatures but very slow
450*C compromise
Yield is high at low pressures so not economical to go higher

6

Manufacture of sulfuric acid

Air + sulfur dioxide -> mixture of gases is cleaned by electrostatic precipitation (400-500*C) (2 atmospheres)

Mixture of gases passed over vanadium oxide catalyst
Oxygen combined with carbon dioxide to form sulfur trioxide
-98% yield

->unreacted gases recycled
---->sulfur trioxide dissolved in concentrated sulfuric acid -> oleum

Oleum acts with water forming sulfuric acid

7

Sulfuric acid uses

Manufacture of detergents
Manufacture of fertilisers
Manufacture of paints

8

Manufacture of ammonia

Nitrogen(air) + hydrogen (natural gas, cracking)

Reaction is reversible, can reach an equilibrium (shift to right, high yield of ammonia)

Low temperature, high pressure (compromise of 450*C or to slow)

Very high pressures (200 atmospheres) -> expensive
(energy required, container, thick walled pipes)

9

Manufacture of ammonia general

Catalyst used : many metals will work
Most economical is iron

Only 15% of hydrogen and nitrogen converted to ammonia

10

Uses of ammonia

Manufacture of:
Fertilisers, nitric acid, nylon