TITLE: Preparation of 2-butanone
INTRODUCTION: The goal of this experiment was to prepare 2-butanone from 2-butanol. Chromic acid was used in this experiment to in order to prepare 2-butanol. Cr (VI) is rather orange, but Cr (III) is dark green - therefore by oxidizing the alcohol (2-butanol), an orange Cr (IV) is reduced to green. NMR and IR tests were taken to determine the result, and the crystallized derivative of this product was obtained.
PROCEDURE: The experiment followed the instructions in the lab manual, except for the empty heating mantle, which our TA advised us to use with sand instead of heating it empty.
RESULTS AND CALCULATIONS:
Weight of crude product
Density of 2-butanone: 0.805 g/mL
Volume of crude product: 4.5 mL
Mass of crude product:
% yield product
% theoretical yield: 2.206 g
% actual yield: 3.6225 g
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Weight after simple distillation
Volume of product: 2.2 mL
Mass of product: 1.771 g
Percent yield of redistilled product
Melting point of derivative: 230˚C -236˚C
CONCLUSION
In this experiment, 2-butanone was prepared from 2-butanol, oxidized by chromic acid. The percent yield of the product is 164.21 %, which is more than the theoretical yield. This happened because steam was distilled along with the 2-butanone at higher temperature. However, this was not a mess, because the product was redistilled with simple distillation, and the correct compound was obtained later by achieving an 80.28 % of redistilled product. Getting a 100 % yield might be impossible, but this is the closest to perfection, because there are always some product lost in the air while distilling, and some in the Erlenmeyer flask with the drying magnesium sulfate.
The derivative of this product was obtained by adding the 2-butanone, freshly made, with 2,4-dinitrophenylhydrazine solution (DNP) to create 2,4-dinitrophenylhydrazone. This compound is solid, and stable as it is