ninhydric1
Hazard to Others
Posts: 345
Registered: 21-4-2017
Location: Western US
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Separation of Thiourea from Sulfamic Acid
Upon acquiring Tarn-X from my nearby Home Depot, I have tried to plan a separation of the two substances.
At first, I thought about precipitating sulfamic acid as a salt, but as not_important has said in this thread (http://www.sciencemadness.org/talk/viewthread.php?tid=6352#p...), all sulfamate salts are soluble in water, which completely ruins my plan.
Then I thought about the differences in solubility in water. Wikipedia says that thiourea has a solubility of 0.142 g/mL, but the solubility of
sulfamic acid is stated as "moderate" but was found on ChemicalBook with a solubility of .243 g/mL. So fractional crystallization could be possible,
but I'm not sure.
Distillation is not possible. How about solvent extraction? According to this website (http://www.inchem.org/documents/cicads/cicads/cicad49.htm), "thiourea (CAS No. 62-56-6) is a white crystalline solid. It is soluble in water (137
g/liter at 20 °C), soluble in polar protic and aprotic organic solvents, and insoluble in non-polar solvents." Wikipedia says that sulfamic acid is
"moderately soluble in DMF, slightly soluble in MeOH, and insoluble in hydrocarbons", which obviously means it's polar (well, from the start it's
known that both are polar molecules). So this won't work unless I find an exclusive solvent that dissolves one but no the other.
Does anyone have any procedures/input on this separation?
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experimental
Harmless
Posts: 21
Registered: 9-7-2017
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Mood: curious
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If you're just after thiourea, I suggest you try to see if you can buy it directly. I did, and could find it relatively easily.
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