126 PRACTICAL ORGANIC CHEMISTRY mainder of the heating may cause the solution to "bump": if this bumping becomes too vigorous, remove the flame for a few minutes to allow the solution to cool slightly and thus to ensure it is not superheated, then add some fragments of unglazed porcelain down the condenser, and continue the heating. When the I^ hours' boiling is complete, preheat a Buchner funnel and flask by pouring some boiling water through the funnel with the filter-paper already in position, and then quickly filter the boiling solution. Transfer the filtrate to a beaker to cool, and then wash the insoluble residue of diphenylurea on the filter twice with hot water, and drain thoroughly. Cool the filtrate in ice-water; the monophenylurea separates as colourless needles. Filter at the purnp and drain well. Recrystallise the crude product from boiling water, as in the previous preparation. Yield of monophenylurea, 2-5-3 g.; m.p. 147°.
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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.