Polymerisation, Hydrogenation

Don't know the processes of polymerisation or hydrogenation?? I've summed them up here as I struggled with them!!

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Polymerisation means joining together lots of small alkene molecules
(monomers) to form very large molecules- these long-chain molecules are called
polymers.
The equation is:
Pressure and Catalyst
General: Many monomers > One Polymer
| | | |
Example: n(C=C) > (CC)n
| | | |
Ethene Polyethene
(Double Bond) (many single bonds joined)
Hydrogenation
Unsaturated vegetable oils are liquid at room temperature. They can be hardened
by reacting them with hydrogen in the presence of a nickel catalyst at about 60
degrees centigrade. This is called hydrogenation.
H. H. H. H.
| | Nickel Catalyst | |
C = C + H2 > H C C H
| | | |
H. H. H. H.
The hydrogen reacts with the double bonded carbons and opens out the double
bonds. Hydrogenated oils have higher melting points than unsaturated oils so
they're more solid at room temperature.
Margarine is made from partially hydrogenated vegetable oil- turning all the
double bonds in vegetable oil into single bonds would make margarine too hard
and difficult to spread.
However partially hydrogenating vegetable oils creates what we call trans-fats
and the evidence suggests that trans-fats are very bad for you.
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Unsaturated vegetable oils can be hardened in the presence of a nickel catalyst
at about 60 degrees centigrade. This is Hydrogenation.…read more

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