Hodgkinson - the answer to your chemistry problem

[WotTheFook]

Hi,

Your problem is perhaps you are getting an azeotrope of the alcohol and the water, the alcohol will also be hygroscopic and will gradually absorb water.

The answer (using kitchen stuff you should have around) is to heat some table salt or baking powder to make it anhydrous (to drive off the water of crystallisation).

Then you allow it to cool and add it to the alcohol. You should stand a much better chance of removing the final water content that way.

BTW, I was an industrial chemist for 25 years in the oil industry.

:-D

WTF

[WotTheFook]

@ Hodgkinson

I would bake the powder (whichever you decide to use) just before you use it and add it to the distilled alcohol, followed by a filtration process.

You may also be able to percolate the alcohol through a filter paper containing the anhydrous powder, although you are risking the powder caking up and blinding the filter.

Once the alcohol has flashed off the powder, you should be able to re-use it, as all you are doing is removing and adding back the water of crystallisation to the powder.

You could also pack a column with a drying agent and attach it above the distillation flask, to remove the water as it distills. The problem with this is you may not know that your drying agent is spent, unless you use something like copper sulphate or cobalt chloride, which change colour with the water of crystallisation present. Copper sulphate goes from white to blue, cobalt chloride goes from blue to pink.

[WotTheFook]

@ Hodgkinson

The slowing down you describe towards the end of your distillation is direct evidence of an azeotrope forming, i.e. the alcohol and water form a constant boiling point mixture (it will be below 100C) and you end up at a point where you can't separate them by distillation.

Are you planning to scale up this process? If so, I would read up about a company called Chemstar that used to be local to where I work. They had the bright idea of distilling ink to recover the solvent and sell it back to the printers, all went well until a fire started one night and the results were catastrophic :-o .

http://carrbrookvillage.users.btopenworld.com/cowbury.htm

http://www.hse.gov.uk/comah/sragtech/casechemstar81.htm

I am a Health & Safety Manager by trade; I would be negligent if I didn't urge you to be careful with what you are doing and keep a fire extinguisher handy.

[WotTheFook]

It shouldn't get through the filter paper; go for it!!

[WotTheFook]

Eh?

Magnesium sulphate is soluble to a degree in water, it's one of the salts that make water "hard". That test proved nothing.

MgSO4 is insoluble in alcohol and it's this property we are exploiting as the drying agent. Dry some out in the oven then add it to some alcohol, it won't dissolve, but it can be filtered out.

For a hydrometer, you will need something in the range 0.750 to 0.800 as the SG if IPA is about 0.790, if memory serves. Try the Scientific Glassblowing Company in Oldham or BDH / Fisher Scientific (easily Googled), they should carry these in stock.

If you get stuck, PM me and I'll give you my phone number.

[WotTheFook]

@ Hodgkinson

You could also use Sodium Carbonate (Soda Ash) as the drying agent, the anhydrous salt works just the same as Magnesium Sulphate. If I recall correctly, Soda Ash doesn't cake up as much as MgSO4.

I agree, a Buchner funnel or some sort of vacuum filtration like some Millipore kit would help things along nicely, it can get expensive though. For the vacuum side of things, get a venturi to fit onto the tap to generate the vacuum, it's cheaper than a pump and there are no parts to break.

I get the feeling your learning curve is going to get a lot steeper starting in September..... :-o  :-)

[WotTheFook]

:idea:

For the condenser, you could rig something up using microbore (10mm)copper central heating pipe, as long as you can connect it to the heated vessel. I am thinking along the lines of a strong metal container with a screw cap for filling, with the condenser tube silver soldered to the cap. Any DIY superstore will carry microbore central heating tubing and this can be easily coiled and put into a bucket of water for cooling.

Devices like this have been distilling "moonshine" for 100s of years....

 ;-)

[WotTheFook]

@ bloodline and Hodgkinson

Science abuse it great as long as you know what you are doing, I love programmes like Brainiacs and Mythbusters for that reason.

Besides, once you have nailed the concept behind a process, you can adapt it, as you already have discovered...;-)

I blew a mate's kitchen to bits with a still once, he forgot to turn the condenser water on. His wife wasn't too impressed and neither were the Fire Brigade, mind you, the Fire Officer didn't figure out what was going on.... :-D  

[WotTheFook]

@ Hodgkinson

Tension's access has been granted.

@ bloodline

Poon, is that like Pr0n, only different, or do you mean poontang?

LOL

[WotTheFook]

@ Hodgkinson

Careful mate, that sounds like a wardrobe full of anoraks you have going on there, although it could explain a lot..... :-o  :-D

LOL

[WotTheFook]

It seems that bloodline isn't into hardware pr0n....

PMSL!!