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Sodium Sulfate

Started by guyincognito, May 22, 2002, 11:50:00 PM

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guyincognito

Swim was looking for cheap sodium sulfate(for drying dcm and product) and found it for like $1.44 a kg (swim pays way more for lab grade anhydrous).

What is the moisture content of regular (used for detergents etc) sodium sulfate?  Can swim use it to dry? Could it be oven baked to remove water then used?  Or just use twice as much?

Trying to get one more thing without having to goto chem store.

PrimoPyro

It is either the anhydrous salt (doubtful) or the decahydrate, which has zero drying capability as is. The salt loses .10H2O (the decahydrate) at only 100C, so heat it to 150C in the oven to speed the process up, and bake it for........I dunno, 30-45 minutes should be good, if not overkill. But better safe than sorry, right? Right.

Don't leave the post dried salt out in the open or it will re-absorb moisture from the air. Also, do not pluverize the chunks into dust or even small granules, or you will have nasty cloudy solvents when you go to dry them, and it will take years to settle. (not literally, but a long time!)

Leave them in the small rock-salt sized chunks they come in, and just bake them.

                                                  PrimoPyro

Vivent Longtemps La Ruche! How's my posting? Call 1-800-EAT-SHIT

Osmium

Drying agents should always be finely powdered. Na2SO4 is a rather slow acting one, and when there's lots of fine stuff in your solvent to be dried then you used too much anyway. Wet spend drying agent will clump and sink to the bottom instantly. As long as the fines are still floating inside you don't need to add any more.

I'm not fat just horizontally disproportionate.

PrimoPyro

Eh?

Well then logically, Im adding way-the-fuck-too-much!  ;D

BooWho

Whay not just use the heptahydrate after oven drying?
Bake Ep***s Salt at 400 for 2 to 3 hours. Break into med to large chunks. Store in ziplock bags.
Use by placing chunks in a doubled filter and pour solvent thru filter at least twice.
Works everytime for Boo...

My rhythm box is sweet, never forgets a beat, Its always high, so am I.

Rhodium

Ep***s Salt

You may spell out Epsom Salt as much as you want to, it's not like they are going to withdraw it from the market because we are making drugs with it.

guyincognito

Swim is using it (sodium sulfate) in a buchner to dry dcm (that has honey in it) - not actually putting it into a solution.  If that makes a difference. 

So its ok to use cheap (not anyhydrous) sulfate, just should oven bake it first?  (It is totally the same substance only with water in it?)

So all the chem company does is remove the water and jack up the price 20 times?  Swim should start chem company.

Rhodium

Epsom salt is Magnesium Sulfate, and yes - the only difference between it and the dry stuff at the chem supplier is that Epsom is MgSO4*7H2O and the dried one only has on average one water of crystallization left. There is also a purity factor, but that difference is so small it is of no concert to us.

You only put the MgSO4 in the buchner and filter? That is not especialy effective - the contact time between the solution and the salt is less than a second if you do it like that.


From the article "sodium and calcium sulfates are surprisingly ineffective..."
% of drying after 15 minutes with 10% w/v dessicant

Dessicant         % of drying
4A Molecular Sieves      99
Calicium Chloride (powder)   86
Calcium Chloride ( pellet)   84
Magnesium Sulfate      80
Molecular Sieve (beads)      65
Calcium Sulfate         22
Sodium Sulfate         18




As you see - this is the amount of drying after 15 minutes - after one second you haven't dried the liquid at all, perhaps only removed actual drops of water sailing in your non-polar solvent.

Here is a proper procedure:

http://orgchem.colorado.edu/hndbksupport/drying/drying.html


Here are supporting pictures:

http://orgchem.colorado.edu/hndbksupport/drying/images/daseq.html




guyincognito

swim is using sodium sulfate (not magnesium - are they interchangable?)- is it the same problem - so doing it too fast wont get the water out?

Swim dries the dcm just before hcl gassing it, and swim hasn't dried the gas either - (uses 36% hcl and sulfuric and salt to make gas)

guyincognito

so placing 100 grams of sodium sulfate in a buchner and vacuum filtering the dcm (with product) through it wont pull vey much water?

Can the sodium sulfate be placed directly into the dcm?  and left for 20 minutes? 


karl

Yes you can. Obviously you should rinse the salt with dry dcm after

guyincognito

should swim be using sodium sulfate or Magnesium sulfate (dried epsom salt)?

And both are fine to put directly in the dcm, then let sit, then buchner thru more sodium sulfate or magnes sulfate?

karl

Exactly.
Both will do the job but Na2SO4 is slower, just don't use CaCl2 if you have alkaloids in there.
TFSE will reveal some more info on this.

cheeseboy

Victoria's silicalgel aquired at the nursery is the SHIT you want. You can just re use it and reuse it and it's gritty like fine sand not podwery fly away shit like ep**m salts.LOL

May De Sorce Bee Wit Chu-Always