Industrial importance of alkenes

Question 1

What does Ethene make?

Answer 1

 1,2 – dichloroethane, ClCH2CH2Cl – degreaser/paint remover.
 Ethane -1,2 – diol, HOCH2CH2OH – Antifreeze/making polymer such as Terylene.
 Ethanoic acid, CH3COOH – vinegar in organic synthesis.

Question 2

What is a Polymer?

Answer 2

A polymer is a long molecular chain built from monomer units. Monomer is a small molecule that combines with many monomers to form a polymer.

Question 3

What is Addition Polymerisation?

Answer 3

Addition polymerisation is where unsaturated alkene molecular (monomers) add on to a growing polymer chain one at a time, to form a long saturated molecular chain.

Question 4

What are monomers like?

Answer 4

Monomers are unsaturated and have a double bond. Addition polymers have saturated chains with no double bonds.

Question 5

What is Radical Polymerisation?

Answer 5

Radical polymerisation requires temperatures of 200 C/high pressures – leads to branching of the polymer chain and production of polymer mixtures. Poly(Phenylethene), Poly(Styrene), branched Poly(Ethene).

Question 6

What is the Ziegler-Natta process?

Answer 6

Ziegler-Natta process involves catalysts such as TiCl3/ Al(C2H5)2Cl at 60 C. Alkene passed over catalyst – slow conversion rate. Unreacted alkene recycled/passed over catalyst - most common method for non-branched Poly(Ethene).