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190303458 2013-4-15 01:22 PM

questions about purification

In the experiment of preparing 1-bromobutane from 1-butanol, after obtaining the organic layer, it should be purified. In purification of the organic layer, it should be washed successivelly with water, sodium bicarbonate solution and water again. I think the sodium bicarbonate solution is used to remove the remaining conc. sulphruic acid. What substance is removed by the water before and after the washing by sodium bicarbonate solution ?

Zzlaz 2013-4-15 09:26 PM

should be neutralization, right?

salt is formed in this case.

190303458 2013-4-16 10:49 AM

[quote]原帖由 [i]Zzlaz[/i] 於 2013-4-15 09:26 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358575071&ptid=21766337][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
should be neutralization, right?

salt is formed in this case. [/quote]Washing by sodium bicarbonate solution is neutralisation. But I don't know what substance is removed by the water before and after the washing by sodium bicarbonate solution ?

Zzlaz 2013-4-16 10:33 PM

which method did you use for the conversion of 1-butanol to 1-bromobutane?

190303458 2013-4-17 02:15 AM

[quote]原帖由 [i]Zzlaz[/i] 於 2013-4-16 10:33 PM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358671683&ptid=21766337][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
which method did you use for the conversion of 1-butanol to 1-bromobutane? [/quote]1-butanol+NaBr+conc. H2SO4

Zzlaz 2013-4-18 08:55 PM

[quote]原帖由 [i]190303458[/i] 於 2013-4-17 02:15 AM 發表 [url=http://www.discuss.com.hk/redirect.php?goto=findpost&pid=358690303&ptid=21766337][img]http://www.discuss.com.hk/images/common/back.gif[/img][/url]
1-butanol+NaBr+conc. H2SO4 [/quote]
the rxn should be like this..

CH3CH2CH2CH2OH + NaBr --> (H2SO4)  CH3CH2CH2CH2Br + H2O +NaHSO4 (it depends on the H2SO4 used....)
1. water

to remove unreacted 1-butanol / NaBr

2. sodium bicarboncate

to remove H2SO4/ NaHSO4 (acidic in nature)

3. water

to remove the remaining water-soluble sodium bicarbonate and Na2SO4...?
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