[xshadow]

HI!!!

I have a doubt:
My text book says that polyethylene can be created by this reaction:

n CH2=CH2  >>> "polyethylene "

But someone can tell me how two molecules of ethylene react (the reaction mechanism...the movment of pi bond electrons) to give( i thins) the ethylene's dimer ??

CH2=CH2 + CH2=CH2 = ??

The product is a dimer??
Thanks
And what is its structure? 

[mjc123]

Your textbook oversimplifies. Ethylene does not react with itself without a catalyst or initiator. There is no simple "ethylene dimer."
Try this: https://www.google.co.uk/#q=ethene+polymerisation
And look up Ziegler-Natta polymerisation - the mechanism is quite complex!

[xshadow]

Your textbook oversimplifies. Ethylene does not react with itself without a catalyst or initiator. There is no simple "ethylene dimer."
Try this: https://www.google.co.uk/#q=ethene+polymerisation
And look up Ziegler-Natta polymerisation - the mechanism is quite complex!

I'll read that, thanks for the moment

[Enthalpy]

One ethylene dimer would be cyclobutane, but it's obtained through a different process, with UV light.

An other dimer is 1-butene, but you won't observe it in a polymerization process.
https://en.wikipedia.org/wiki/1-Butene
Refineries either make isobutene of it and then alkylates for high-octane fuels, or metathese it with ethylene to propylene, from which polypropylene is made.