Question

Name the catalyst used in the preparation of high density polythene.

Answer 1

A very well known catalyst is used. The process is also known as coordination polymerization. This contains aluminium, titanium, chlorine elements along with carbon compounds.

Complete step by step answer:
-Ziegler-Natta catalyst is a mixture of two compounds named as triethyl aluminium and titanium tetrachloride. This catalyst is used in the preparation of high density polyethylene and polythenes.
The molecular formulas are: ${({{\text{C}}_2}{{\text{H}}_5})_3}{\text{Al and TiC}}{{\text{l}}_4}$
-The Ziegler-Natta catalyst was discovered by Karl Zeigler. It contains alkyl derivative of aluminium and titanium tetrachloride. It is used in the polymerization reaction and to produce high density polythene. Due to the excellent work in this branch Zeigler and Nata were awarded with the Nobel prize in 1963. Zeigler-Nata catalysts can broadly be classified into two types based upon their solubility. They are heterogeneous supported catalyst and homogeneous catalyst.
-Ziegler-Natta catalysts generally contain a transition metal halide with some organometallic compound.
-Ziegler-Natta catalyst is used for the production of both high density polythene and low density polythene. It is also used in the production of olefins, polybutylene, thermoplastics, crystalline polypropylene and in nano-composites.
-High density polythene is a polymer made from the monomer in ethylene. It is a very high strength. Due to its various properties it is very popular. It is moldable and it is resistant to corrosion. It has high strength and it is recyclable but non biodegradable in nature. It is widely used in bottle caps, bottles, in printing filaments etc.

Note:
There are certain limitations for the second Ziegler-Natta catalyst. It is not effective for some monomers to make a polymer. For example polyvinyl and acyl chlorides cannot be generated from Ziegler-Natta catalyst.