March 28, 2024, 02:39:41 PM
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Topic: How to remove 1-pentanol from 1-bromopentane?  (Read 3587 times)

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Offline AWK

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Re: How to remove 1-pentanol from 1-bromopentane?
« Reply #30 on: November 28, 2020, 06:55:24 PM »
If you get the condensate below 100°C and it separates into two layers with the organic phase floating on the water surface - this is pentanol. Bromopentanol has a density greater than that of water to keep it below the surface of the water. Without the rectification column, the condensate collected even below 100°C will contain traces of bromopentane which will be dissolved in the pentanol. I am rather sure that pentanol and bromopentane form an azeotrope and I expect boiling points of the order of 120-125°C.
Drying solutions containing alcohols with CaCl2 is pointless because alcohols form solvates with CaCl2 (probably with pentanol as well) and there will always be some water left in the dried preparation.
If you have a refractometer, distill a small amount of your preparation with the addition of water and check whether the refractive index of the last fraction increases.
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Offline lukas.stib

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Re: How to remove 1-pentanol from 1-bromopentane?
« Reply #31 on: November 29, 2020, 02:44:13 AM »
I don't have a refractometer. OK should I perform fractional distillation? That I would mix the product and the second distillate? I don't like fractional distillation for high-boiling substances, because it's more difficult, I'll have to wrap the column with foil or rags to keep warm.
Fractional distillation is much more efficient than simple I think.
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