View Full Version : MgSO4 + EtOH for dessication?
incorporated
2008-06-08, 19:00
Is this plausible? Anyone ever try it? There's always a big hassle when it comes to getting to the higher percentages of purity for ethanol and I was curious as to whether or not this would be worth trying. I just distilled some vodka I had, so I'm gonna try some experiments with Epsom salt unless someone here can tell me it won't work.
Pictures will be included, for sure. The party balloon and duct tape method worked wonderfully for the condenser. Thanks to everyone on their input on that subject.
stateofhack
2008-06-08, 21:48
Is this plausible? Anyone ever try it? There's always a big hassle when it comes to getting to the higher percentages of purity for ethanol and I was curious as to whether or not this would be worth trying. I just distilled some vodka I had, so I'm gonna try some experiments with Epsom salt unless someone here can tell me it won't work.
Pictures will be included, for sure. The party balloon and duct tape method worked wonderfully for the condenser. Thanks to everyone on their input on that subject.
I hope you distilled it with a fractionating column and slowly controlling the temperature :), after that dump MgSO4 in the oven at 400°C for 5 hours. Dump it in your distilled EtOH to dry it and filter it out.
But...molecular seaves (A2 if i recall are the one i use) are you best bet: cheap and recyclable and efficient:)
incorporated
2008-06-09, 02:40
I didn't use a fractionating column, that's why I'm sure there are azeotropes a-plenty and proper desiccation needed. I'm a fan of the oven dried MgSO4 as opposed to the microwaved (it always turned out to be a solid, brittle mass that proved unworkable), so I'll definitely be using the oven. You suggest five hours, though? I've always been pretty happy with the results obtained by a two hour cook, but I'll try it your way since it couldn't hurt.
hydroponichronic
2008-06-09, 04:53
When I want to dessicate my MgSO4, I just put it in a tin-foil pouch and hold it above the stove. When it stops bubbling, it's done. 5 minutes, max.
incorporated
2008-06-09, 05:09
I'm using the MgSO4 AS a desiccant. Drying it is no problem. I'm just wondering if it will help remove water from ethanol.
it will to a point.
if there is a fair bit of water you will find the mag sulfate will dissolve into it, rather than just being hydrated in the crystaline state.
it should only really be used on trace water, it won't dry out 40% vodka or anything.
incorporated
2008-06-09, 08:54
That's what I was hoping to obtain by the distillation. I will probably weigh an amount of dried MgSO4, apply it to the EtOH, filter, redry and take a new weight and then end up doing a couple of distillations on the same sample and seeing if there is a difference. I've got so little free time these days that it's ridiculous, though, so it could be a while before I update.
Do it more than once. Once to get the most water out and then again to make it as dry as possible. Because theoretically the monohydrate and higher is a weaker drying agent than the dry salt. At a certain point you can add all the monohydrate to it you want and you still won't get it as dry as you would by finishing with a little really dry MgSO4, because of the vapor pressure of the water in the hydrates.
stateofhack
2008-06-09, 13:41
When I want to dessicate my MgSO4, I just put it in a tin-foil pouch and hold it above the stove. When it stops bubbling, it's done. 5 minutes, max.
Not enough! Seriously in the oven 4-5 hours with the temperature stated in the above post is the way!
I didn't use a fractionating column, that's why I'm sure there are azeotropes a-plenty and proper desiccation needed. I'm a fan of the oven dried MgSO4 as opposed to the microwaved (it always turned out to be a solid, brittle mass that proved unworkable), so I'll definitely be using the oven. You suggest five hours, though? I've always been pretty happy with the results obtained by a two hour cook, but I'll try it your way since it couldn't hurt.
You should have used one :( i will be using one tonight, i will let you know how it works out, although i believe i am out of drying agents. But seriously, molecular sieves= ftw
I'm using the MgSO4 AS a desiccant. Drying it is no problem. I'm just wondering if it will help remove water from ethanol.
I am not to sure about it neither :( doesn't hurt to try tho' ;)
it will to a point.
if there is a fair bit of water you will find the mag sulfate will dissolve into it, rather than just being hydrated in the crystaline state.
it should only really be used on trace water, it won't dry out 40% vodka or anything.
So i could use it after a careful fraction distillation of vodka to remove any last traces?
i can't think of any reason why it wouldn't work. im 99% sure it isn't soluble in ethanol. don't be afraid to leave it for an hour, get a nice heap down the bottom of the solution and just walk away. diffusion will ensure that the water is evenly spread out and is absorbed by the salt. if you shake it up or stir too enthusiastically you risk just dissolving it and then another distillation is the only way out.
stateofhack
2008-06-10, 13:46
Vodka distilled with some success, pictures and more later on tonight :)
Lost pictures because of a crash :( All i can tell you is that i obtained what i believe is 90% EtOH, i will try run it in a benzocaine synth as to see, because i have no other way (yet) to test it :)
Out of 250 ml of Vodka i got 110 ml, stopped the distillation when the temperature got to high :)
i can't think of any reason why it wouldn't work. im 99% sure it isn't soluble in ethanol.
"Sparingly soluble"...
start with a bottle of everclear or a foreign eqivelent