Organic 2 Review Problem 138

Organic 2 Review Problem 138 - 122 P RACTICAL O RGANIC C...

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122 PRACTICAL ORGANIC CHEMISTRY mixture starts to effervesce gently. Adjust the heating so that the acetonitrile distils slowly over; use a small conical flask as a receiver, and continue heating until no more distillate can be readily obtained. The crude acetonitrile contains as impurity chiefly acetic acid, arising from the action of phosphoric acid on the acetamide. Therefore add to the nitrile about half its volume of water, and then add powdered dry potassium carbonate until the well-shaken mixture is saturated. The potassium carbonate neutralises any acetic acid present, and at the same time "salts out" the other- wise water-soluble nitrile as a separate upper layer. Allow to stand for 20 minutes with further occasional shaking. Now decant the mixed liquids into a separating-funnel, run off the lower carbonate layer as completely as possible, and then pour off the acetonitrile into a 25 ml. distilling-flask into which about 3-4 g. of phosphorus pentoxide have been placed immediately
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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