Submitted by P. Carneades C from YuanHe Institute

Procedure

A mixture of 5.0g of diphenylketone, 3.0g of hydroxylamine hydrochloride, 5.0g of sodium hydroxide is placed in a 150mL single-necked flask. Then cover the mixture with ethanol immediately (Note 1) and a few drops of water is added. Heat the flask on a steam bath for 10 minutes. 20 mL of concentrated hydrochloric acid is dissolved in 100 mL of water. Afterwards, pour the reactant into this solution, a considerable amount of powder-like crystal (crude product) is separated out and float on the surface of the liquid. Filtrate the mixture and recrystallize the cake in 40mL of ethanol (Note 2) . 4.0g of colourless acicular crystal (pure product) is obtained. The final yield is 81.4%


1. Ethanol must be added with stirring as quickly as possible. Or the hydroxylamine released will decompose spontaneously.
2. Recrystallizations with ethanol must be carried out on a hot-water bath. Organic solvents like ethanol, aether or something can be ignited easily by flames or sparks.

Discussion

The order of mixing the reactants requires some further adaption. The decomposition of hydroxylamine must be prevented.


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