Hey everyone,

Questions for my distillation setup.

I've always had the luxury of using Glas-Col heating mantles and now that I don't have access to them anymore I'm exploring my options. The one that I keep coming back to is the oil bath. What is the general concensus from some of you more expeirenced folks here?

For the oil bath setup, I was planning to use this single burner electric hotplate: http://tinyurl.com/522ak2 (http://tinyurl.com/522ak2) to heat a pyrex bowl or metal pan and use a high smoke point oil. Possibly even brake fluid, as I've heard that works quite well also, but the bad smell of brake fluid makes me wary of that option. The problem is I wouldn't be able to remove the heat source quickly if need be as the hotplate is a little to big to set on a lab jack as far as stability concerns are involved. I'm sure it'd be possible to modify the jack, but the reason I wanted to go this route is financial, so a jack would just add to the cost. Any suggestions on this front?

The other question is about a pump for the condenser water. Obviously I want to use the coldest water I can. I tested the water from my tap and after running it through the condenser for half an hour there was very little condensation on the outside of the condenser jacket. Plus the condenser wasn't cold, but rather cool to the touch. So, it looks like I'll need to use ice-water and a pump. At least to make me feel better. And here we go with another link. This pump seems like it would fit the bill perfectly:

http://tinyurl.com/4ram46

The home tap that I'd come out from if it ran cold enough water only runs about 30-40 gph and it seems to run at the proper flow without worrying about "blow-outs". So it seems like the above pump thrown into a sink of ice-water would work fine. What do you all think?

I'm open to all suggestions and advice. If any. Thanks guys.


P.S. I'm thinking a great source of steam for doing the steam distillations would be using a pressure cooker. You guys ever try that? Using the little outlet that you would normally put the round weighted steel "steam pressure thingy" on. Just run a hose from there to the inlet for the steam.

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Thanks.

I'll carry that advice with me always?

Possibly next time I'll do pictograms for you.

I personally use:

Water baths for heating and distilling solvent mixtures with BPs lower than say... 60 degrees C. I've only ever used a water bath once, for distilling diethyl ether.

Sand bath for nearly everything else.

Oil bath, (silicon is best (again, IMO)) for precise work on smaller volumes, where temperature control is important.

My hotplate is a really cheap affair, much the same as the one in the link, but has a solid metal top to it. It pretty much permanently has a folded over piece of aluminium foil to stop chemicals from raping the iron top.

I believe a lot of people use oil baths, and is obviously nice and easy to set up, just pouring it into the container around your flask, peanut oil I hear is supposed to work well as a cheap substitute to the more expensive oils. Obviously you want to avoid anything that will begin smoking or emitting tasty noxious fumes at high temperatures, hence why I think silicon oil is the absolute best.

Tap water will honestly be fine for most applications, when I distil or reflux with a source of running water, I'll use a slow flow of water, has never presented any problems. Saying that, I personally use a medium big bucket half full of water and a few ice packs / ice cubes, with a tiny submersible pump to keep a slow flow around the condenser. Of course, if you want to distil something like anhydrous ammonia, you are going to want something significantly colder running round your condenser and in your receiving flask.

And yeah, I've thought about that for a steam source, I've never had to apparatus or need to really do a steam distillation though, other than when I was experimenting with cloves and clove oil. I would be interested to hear how it all goes if you decide to have a go!

I reckon I would go with the sand bath, as Von Bass said, simply because oil baths are annoying when they spill or drip oil everywhere. If you can't get hold of a dry-syn or equivalent, sand should be fine for most purposes.

With regards to the condensor, I think the pump in bucket idea is better than just a flowing tap, simply for the waste issue. You mentioned that you didn't see any condensation when running water through the condensor - this is fine and you would probably not expect to, unless it is particularly humid where you are. You have to remember, in that case you would be trying to get water vapour in the air to condense on the glass, whereas in a distillation setup, you are working with an atmosphere of vaporised solvent, which will hapily condense once it hits the relatively cold surface of the glass.

I'll have to read up on the sand bath.

I think my first go on this new setup will be a distillation of some good old fashioned ethyl alcohol. It's legal where I currently reside.

After that I'm going full steam ahead.

I'll have to read up on the sand bath.

I think my first go on this new setup will be a distillation of some good old fashioned ethyl alcohol. It's legal where I currently reside.

After that I'm going full steam ahead.


If you expecting to pull apart methanol and ethanol, you're gonna need a decent fractionation column...

Also, for steam distillations, I would imagine that just doing it in a standard way might well be easier then trying to hook up a presure cooker to your glassware. Dunno though - might be a stroke of genius!

If you expecting to pull apart methanol and ethanol, you're gonna need a decent fractionation column...

Also, for steam distillations, I would imagine that just doing it in a standard way might well be easier then trying to hook up a presure cooker to your glassware. Dunno though - might be a stroke of genius!

this thread just got my attention. so your saying getting methanol and ethanol apart can be done at home? everyone says its impossible due to the 10 degrees difference.

so all i would need is a really good fractional column, a cheap reflux, a cheap metal hotplate and brake fluid and sit a pyrex cup of methylated spirits in it with a thermometer to keep it under 70c. my hopes have been raised dont make me cry

this thread just got my attention. so your saying getting methanol and ethanol apart can be done at home? everyone says its impossible due to the 10 degrees difference.

so all i would need is a really good fractional column, a cheap reflux, a cheap metal hotplate and brake fluid and sit a pyrex cup of methylated spirits in it with a thermometer to keep it under 70c. my hopes have been raised dont make me cry

well...

sort of...

You'll need to be able to perfom a fractional distillation PATIENTLY, and confidently... If you're never done it before, I'd be tempted to give it a few goes without consuming any end products so you know what you're doing.

You WILL need a good set-up (i.e. RB flask, still head, fractionating column with appropriate packing material, thermometer with a suitable ground glass joint, liebig condensor, water pump, pig, and receiver flasks), and presumably you will also need to re-distill a couple of times to bring it to acceptable purity...

well...

sort of...

You'll need to be able to perfom a fractional distillation PATIENTLY, and confidently... If you're never done it before, I'd be tempted to give it a few goes without consuming any end products so you know what you're doing.

You WILL need a good set-up (i.e. RB flask, still head, fractionating column with appropriate packing material, thermometer with a suitable ground glass joint, liebig condensor, water pump, pig, and receiver flasks), and presumably you will also need to re-distill a couple of times to bring it to acceptable purity...

cheers thats a huge help, any ideas on where to get a good column, ive seen them on ebay but im pretty sure chinese made doesnt count as "good quality"

also it occurs to me that where distilling off the methanol, something we dont plan to keep, so why use the column and condensor why not just let it distill into the ozone and wear a mask (and doing it outside) and just let it distill untill you dont see anything else evaporating.

also it occurs to me that where distilling off the methanol, something we dont plan to keep, so why use the column and condensor why not just let it distill into the ozone and wear a mask (and doing it outside) and just let it distill untill you dont see anything else evaporating.


Because that's not how it's done.

If you just boil a beaker of a mixture of alcohols and water on a hotplate outside, you're not going to have much control over what evaporates away. The idea is similar to understanding why you are using a fractionating column rather than a simple distillation...