Sciencemadness Discussion Board

Making Pure Sodium Iodide the Easy Way?

LuckyWinner - 1-12-2020 at 10:20

this was done:

Iodine and NaOh reactions a la
(6)NaOH + (3)I2 --> NaIO3 + (5)NaI + (3)H2O

exact stoichiometric ratios were followed.
this yielded a white solution without any yellow tint.

the calculation may does not account for any iodine that is
lost mechanically by its previous KI extraction...

this can cause a slight excess of NaOh when making Sodium Iodide
and will cause it to be contaminated with it.

separating this NaOh out seems to be a pain in the ass.
since it reacts with acetone and is also soluble in ethanol, water,...


the easiest way to prevent a NaOh contamination is by
adding NaOh to a hot aqueous Iodine solution and KEEP the
solution at a slightly yellow tint.

this should be the proper indicator for an Iodine excess.

boil down the liquid , filter out the unreacted iodine.
left is a clean NaI + NaIO3 solution?


is this correct or anything better then this?


this NaI is then used for a finkelstein,
there cant be any NaOh impurities present...

rockyit98 - 2-12-2020 at 05:16

mix CaSO3 with I2 in a NaOH media let the CaSO4 settle down top, off NaI solution. CaSO3 can be made by mixing Na2SO3 with CaCl2 it also sink to bottom.

LuckyWinner - 2-12-2020 at 05:29

Quote: Originally posted by rockyit98  
mix CaSO3 with I2 in a NaOH media let the CaSO4 settle down top, off NaI solution. CaSO3 can be made by mixing Na2SO3 with CaCl2 it also sink to bottom.


you mean to

I2 + NaOh = NaI + excess NaOh
this excess NaOh reacts with the CaSO3 as folllows
CaSO3 + NaOH = Ca(OH)2 + Na2SO3

product
Ca(OH)2 is only slightly soluble in water (0.16g Ca(OH)2/100g water at 20°C) forming a basic solution called lime water.

sodium sulfite Na2SO3 , is soluble in water and will then be a contamination.

teodor - 2-12-2020 at 05:37

Will potassium oxalate + I2 reaction work as with bromine, as in Brauer's preparation for "Bromine": "The distilled bromine is reduced to KBr by
dropwise addition to a hot solution of recrystallized, halogen-free potassium oxalate."

rockyit98 - 2-12-2020 at 14:26

Quote: Originally posted by LuckyWinner  
Quote: Originally posted by rockyit98  
mix CaSO3 with I2 in a NaOH media let the CaSO4 settle down top, off NaI solution. CaSO3 can be made by mixing Na2SO3 with CaCl2 it also sink to bottom.


you mean to

I2 + NaOh = NaI + excess NaOh
this excess NaOh reacts with the CaSO3 as folllows
CaSO3 + NaOH = Ca(OH)2 + Na2SO3

product
Ca(OH)2 is only slightly soluble in water (0.16g Ca(OH)2/100g water at 20°C) forming a basic solution called lime water.

sodium sulfite Na2SO3 , is soluble in water and will then be a contamination.
CaSO3(not soluble) + NaOH +I2 -------->CaSO4(not soluble) + 2NaI +H2O