Organic 2 Review Problem 259

Organic 2 Review Problem 259 - PREPARATIONS 243 solid This...

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PREPARATIONS 243 solid. This acyl chloride is used extensively for the preparation of crystalline derivatives of alcohols, phenols, amines and amino-acids (cf. pp. 335, 338 381) Required: 3,5-Dinitrobenzoic acid, 15 g.; phosphorus penta- chloride, 17 g. Assemble in a fume-cupboard the apparatus shown in Fig. 6y(A).* Place 15 g. of 3,5-dinitrobenzoic acid and 17 g. of phosphorus pentachloride in the flask C, and heat the mixture in an oil-bath for i J hours. Then reverse the condenser as shown in Fig. 6y(B), but replace the calcium chloride tube by a tube leading to a water-pump, the neck of the reaction-flask C being closed with a rubber stopper. Now distil off the phosphorus oxychloride under reduced pressure by heating the flask C in an oil-bath initially at 25-30°, increasing this temperature ultimately to 110°. Then cool the flask, when the crude 3,5-dinitro- benzoyl chloride will solidify to a brown crystalline mass. Yield, 16 g., i.e., almost theoretical. Recrystallise from carbon tetrachloride.
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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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