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Topic: Ether synthesis  (Read 7418 times)

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Offline funlovin

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Ether synthesis
« on: October 14, 2007, 10:02:09 AM »
Hi everyone,
I have to synthesize CH3CHCH3 from CH3CH2CH3.
                                  |
                                  OCH3

I think that i should do williamson ether synthesis,so i chose CH3O as an alkoxide,but first i need to synthesize isopropyl alcohol from CH3CH2CH3.Isopropyl alcohol can attack CH3SO2Cl then hydroxide can become good leaving group.After the Sn2 rxn of methoxide i can synthesize my ether.How can i synthesize isopropyl alcohol from propane?
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Offline macman104

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Re: Ether synthesis
« Reply #1 on: October 14, 2007, 02:38:46 PM »
Propane -> 2-bromopropane with free-radical bromination
2-bromopropane to 2-propanol with either direct SN2 coversion, or if you don't think that will work good, you can do

2-bromopropane to 2-iodopropane with NaI in acetone, and then AgNO3 in acetone-water to produce the alcohol.
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Offline sjb

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Re: Ether synthesis
« Reply #2 on: October 15, 2007, 12:59:55 PM »
Quote from: macman104 on October 14, 2007, 02:38:46 PM
Propane -> 2-bromopropane with free-radical bromination
2-bromopropane to 2-propanol with either direct SN2 coversion, or if you don't think that will work good, you can do

2-bromopropane to 2-iodopropane with NaI in acetone, and then AgNO3 in acetone-water to produce the alcohol.

IMO you may have quite a bit of selectivity problems with that first step. How about Propane -> a monobromo-substituted propane (regardless of what it actually is) -> propene (elimination) -> IPA (hydration with acid). One extra step, but may increase overall yield as you're not wasting the 1-bromopropane formed in the first step?

S
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Offline english

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Re: Ether synthesis
« Reply #3 on: October 16, 2007, 11:14:23 AM »
You sure you can't get isopropyl alcohol as reagent grade?
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Offline sjb

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Re: Ether synthesis
« Reply #4 on: October 16, 2007, 02:15:11 PM »
Quote from: sjb on October 15, 2007, 12:59:55 PM
IMO you may have quite a bit of selectivity problems with that first step. How about Propane -> a monobromo-substituted propane (regardless of what it actually is) -> propene (elimination) -> IPA (hydration with acid). One extra step, but may increase overall yield as you're not wasting the 1-bromopropane formed in the first step?

S

Sits corrected, having read through http://www.mhhe.com/physsci/chemistry/carey/student/olc/ch04radical.html, 2-bromination is the major product (and fairly heavily so)
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Offline macman104

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Re: Ether synthesis
« Reply #5 on: October 16, 2007, 05:05:02 PM »
Quote from: g english on October 16, 2007, 11:14:23 AM
You sure you can't get isopropyl alcohol as reagent grade?
Oh...yea, I would imagine you could.  We have some in our lab...
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