Chemical Forums

Chemistry Forums for Students => High School Chemistry Forum => Topic started by: gowadon on September 14, 2012, 05:27:49 PM

Title: Reaction Mechanisms in Addition Reactions
Post by: gowadon on September 14, 2012, 05:27:49 PM

In an addition reaction between a halide (such as bromine water) and an alkene/alkyne (such as propene), the products should be (1-)bromopropane and hydrogen bromide.
   I would like to know why the bromine "wants" to bond to the first carbon in the chain instead of the second. Any thoughts? (My chemistry teacher is beginning to give me more homework so I don't have time to ask her these kind of questions :P)

Title: Re: Reaction Mechanisms in Addition Reactions
Post by: Hunter2 on September 14, 2012, 07:25:26 PM

In case of bromine water you will get isomers of bromine-propanol.

http://www.chemguide.co.uk/organicprops/alkenes/halogenation.html

Check also the  law of Markovnikov

Title: Re: Reaction Mechanisms in Addition Reactions
Post by: gowadon on September 16, 2012, 04:43:15 PM

how would you get bromine propanol when there's no oxygen in the equation to make the neccesary hydroxide?

Title: Re: Reaction Mechanisms in Addition Reactions
Post by: discodermolide on September 17, 2012, 12:22:02 AM

Have a look her for bromine water:
http://en.wikipedia.org/wiki/Hypobromous_acid (http://en.wikipedia.org/wiki/Hypobromous_acid)

Alkenes react with the hypobromous acid to add HO and Br across the double bond. So in your case you will get 2-bromopropan-1-ol