Fractional distillation

Goal : Carry out a fractional distillation to separate propan-2-ol from propanone.

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Hi readers ! This is my new lab experiment ! Please note that due to a lack of time I didn't do the propanone reduction :(

Step 1 ( after the propanone reduction was done by the teacher ) : Getting the propan-2-ol :

I had my reducted propanone in a beaker which I saturated using sodium chloride and then I separated the organic phase.

Step 2 : Purification :

I dried the organic phase using some anhydride magnesium sulfate. Then I distilled it and recovered the fraction between 80 and 85°C.

Step 3 : Purity control :

To control the purity of my product I measured its refractive index using a refractometer. Mine was at n=1,3750 at 21,5°C so I corrected it at 20°C and I obtained n=1,3757. The theoretical refractive index of the propan-2-ol is n=1,3776.

I also tested my product using 2,4-Dinitrophenylhydrazine and it showed a yellow precipitate which indicates that my propan-2-ol isn't pure and still contains traces of the propanone ( precipitate turns yellow when the 2,4 DNPH reacts with a cetone ).

Step 4 : Theoretical spectra :

Since my school doesn't own any kind of spectrophotometer, we used theoretical spectra (IR and NMR) which I both analized.

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In conclusion, my propan-2-ol was not pure and still had propanone in it. I need to further purify it or try again and do it better ! This lab experiment was fun even if I'm not the biggest fan of fractional distillation :)