Sciencemadness Discussion Board

phenylacetylene from styrene

PeetPb - 25-6-2012 at 02:39

Hi ,
I saw a method how to prepare phenylacetylene from styrene. It's based on bromination of the double bond and then elimination by a base like NaOH. The problem is that I can't get elemental bromine. Or better said, I could get it but I'm a little afraid of it. Could I use chlorination for this ? or is there another way?

thanks

DJF90 - 25-6-2012 at 02:48

You could always generate the bromine in situ, using say HBr and H2O2. Alternatively you may try dilute acid, a bromide salt and an oxidising agent.

PeetPb - 25-6-2012 at 03:10

thanks I'll try to improvise somehow ....

Adas - 25-6-2012 at 08:32

I would assume that when you react NaOH with 1,2-dibromo-1-phenylethane, you will get 1,2-dihydroxy-1-phenylethane. You would probably need a strong dehydrating agent.

Nicodem - 25-6-2012 at 09:00

Quote:
I'll try to improvise somehow ....

To improvise anything you need to have comprehension of how things work. If you want to have a minimum chance of success I rather suggest you to hit the literature. To give you a starting point, see DOI: 10.1016/j.tet.2009.03.034
Quote: Originally posted by Adas  
I would assume that when you react NaOH with 1,2-dibromo-1-phenylethane, you will get 1,2-dihydroxy-1-phenylethane.

Based on what reference? I can't really figure out why would you so naturally assume something that goes against the current level of theory? We even have a domestic reference that goes contrary to what you say: Preparation of Styrene and Phenylacetylene from Polystyrene

solo - 25-6-2012 at 09:53

Reference Information


Environmentally benign electrophilic and radical bromination ‘on water’: H2O2–HBr system versus N-bromosuccinimide
Ajda Podgoršeka, Stojan Stavbe
Tetrahedron
2009, Volume 65, Issue 22, 30 Pages 4429–4439
http://dx.doi.org/10.1016/j.tet.2009.03.034,

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