wild_rabbit
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Pentene hydrobromination
I'm new to organic chemistry and did one of my first organic synthesis and my results were not really as expected. My target product was
2-bromopentane. The route i took was reacting 1-pentene with azeotropic HBr. The mixture was refluxed for 2 hours and left to stand over night. Next
day I decided to do fractional distillation and the result was unexpected. First thing that came over was probably unreacted 1-pentene (b.p. 30°C),
then the second fraction came at 86-90°C which had a strong burned smell, with aroma similar to aromatic sandalwood or something like it. Once this
fraction stopped coming over, what was left in reaction flask was HBr. Expected products were 1-bromopentane (b.p. 130°C) and 2-bromopentane (b.p.
117°C) as a major product. I'm a little confused about where I went wrong. I'm not sure what the second fraction is. Any thoughts or suggestions
would be appreciated. Thanks
[Edited on 7-5-2019 by wild_rabbit]
[Edited on 7-5-2019 by wild_rabbit]
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wild_rabbit
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Sorry to bother again, I'll try getting some input once more.
I still dont have the answer to my original question. Has anyone had success hydrobrominating alkenes?
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Boffis
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Is it possible that the HBr has simply polymerised the pentene and the Bp c90 C is the dimer? Was there much higher boiling material left in the
flask? I have always had problems getting anything other than HI to add across simple double bonds.
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