Sciencemadness Discussion Board

Dihydrazine Sulfate(H10N4O4S)

Rexona - 4-5-2018 at 23:55

How to prepare Dihydrazine Sulfate(H10N4O4S) ?

VSEPR_VOID - 5-5-2018 at 00:26

Hydrazine sulfate can be prepared by the method described in the attached video:
https://www.youtube.com/watch?v=PCovDr4FVNQ


Boffis - 5-5-2018 at 02:41

@Vsepr_void, the compound prepared in the various youtube videos and the various method described on this web site yield hydrazine hydrogen sulphate N2H6SO4 which is sparingly soluble but there is also a dihydrazine sulphate (N2H5)2SO4 which is exceedingly soluble and therefore difficult to prepare solid. However in solution it allows you to have much higher concentrations of hydrazine.

There are two basic routes to its preparation 1) to add more hydrazine to the (mono)hydrazine sulphate and 2) to remove half the sulphate ions.

1) Hydrazine hydrate is added to a suspension of hydrazine sulphate in water (say about 20g in 100ml) until the original salt just dissolves.

2) Treat a suspension of hydrazine sulphate with a warm saturated solution of barium hydroxide (Strontium and calcium hydroxides will also work, though gypsum aka calcium sulphate crystallises slowly and incompletely). 1g of hydrazine sulphate requires 0.66g of anhydrous barium hydroxide (beware; bought barium hydroxide is usually the 8 hydrate!). With calcium hydroxide you may need to use the solid hydroxide and it may also be possible to use an excess of the carbonate. The insoluble sulphate and excess carbonate is simply removed by filtration.

By the way why do you need specifically the dihydrazine sulphate? You can often get away with simply partial neutralisation of the hydrazine sulphate with NaOH until it just dissolves.