In the preparation of the sodium hypochlorite solution it is quite necessary that the mixture be kept cold and be alkaline to litmus paper at the end of the reaction, if good yields of hydrazine are to be obtained.

Since iron is an anti-catalyzer, it is necessary to use distilled water throughout the process.

As a viscolizer, a substance such as starch, glycerol, glue, or gelatine may be used; the last, however, gives by far the most satisfactory results.

In order to obtain a pure white hydrazine sulfate as the first precipitate, it is necessary to cool the hydrazine solution thoroughly and filter it twice before the sulfuric acid is added. Morever, the sulfuric acid must be added slowly and with stirring. If these conditions are not followed, material containing brown particles results.