Sciencemadness Discussion Board

hydrazine synthesis

chemx01 - 9-5-2013 at 08:00

I am currently working on a ethanolic hydrazine synthesis per instruction found at:
"Small-Scale Synthesis of Laboratory Reagents with Reaction Modeling"

but since english isn't my native language i have some trouble with the procedure:

"When all KOH has been added, 120 mL of absolute ethanol is poured into the flask, the contents are well shaken, and stirring of the now fluid mixture in the stoppered flask is continued magnetically for about 30 min. The precipitate of K2SO4 is filtered and washed together with the reaction vessel several times with fresh absolute ethanol until 240 mL of the latter has been added. About 73% of the hydrazine is recovered in solution."

I know that it seems stupid, but i don't understand how much ethanol should I add is it 120ml to reaction+240ml for washing so total of 360ml or do I add 120ml to the reaction and than wash until the total amount is 240ml?
I know that the concentration of hydrazine is easily calculated but I just wanted to clear this problem.

Hexavalent - 9-5-2013 at 09:32

I'd read it as that you add 120 mL of EtOH initially, then wash with 240 mL....

Oscilllator - 9-5-2013 at 23:38

I reckon you add 120ml into the flask, and then add an additional 120ml for a total of 240ml

chemx01 - 10-5-2013 at 05:21

That's the dilema i'm having whether add 360ml or 240ml of Ethanol. maybe rather than speculate i'm going to calculate the concentration by the actual volume i used. I was just curious.