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unionised
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I think ozone has mixed up DCM with chloroform.
BTW, XxDaTxX ,
"DMSO is a cheap solvent that you must have access to. Heat some it in your flask, swirl, decant, repeat. Rinse again with water, then tell yourself
"I will never again extract essential oils with DCM. I will do as XxDaTxX says and steam distill before partitioning in DCM."
"
Why?
Quince seems to have cleaned the glassware without using DMSO (and I would have tried caustic first, then white spirit; DMSO isn't that cheap or
accessible it's also a poor solvent for saturated hydrocarbons and a lot of waxes fall into that group). So far as I can judge he's now after cleaning
up the DCM.
Washing the DCM with caustic to remove the waxy stuff might work but alkaline extractions often give messy emulsions.
For the original extraction of the oils, in general it's better to steam distill out essential oils, not least because water's a very cheap solvent.
OTOH the oils always come over with a lot of water and you will improve the yeild if, in addition to simply separating the oil from the water by
density, you also extract the water layer with a solvent to remove such oil as is dissolved in it. DCM is quite a good choice for this as it's easy to
evaporate off again later.
Oh, also, I wouldn't have refered to the DCM/water azeotrope if it didn't exist and I'm reasonably familliar with the idea of steam stripping for
solvent revovery. I still think it's a weird steam distillation.
I still want to know what this thickening agent/wax that distills below 40C is. Whatever it might be, if it distills over with straight DCM at 39.75C
I suspect it will distill over with the water/ DCM azeotrope at 38.1C so I don't see any advantage to steam distillation to clean up the solvent
(unless the stuff happens to react with water).
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XxDaTxX
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| Quote: | Originally posted by unionised
I think ozone has mixed up DCM with chloroform.
BTW, XxDaTxX ,
"DMSO is a cheap solvent that you must have access to. Heat some it in your flask, swirl, decant, repeat. Rinse again with water, then tell yourself
"I will never again extract essential oils with DCM. I will do as XxDaTxX says and steam distill before partitioning in DCM."
"
Why?
Quince seems to have cleaned the glassware without using DMSO (and I would have tried caustic first, then white spirit; DMSO isn't that cheap or
accessible it's also a poor solvent for saturated hydrocarbons and a lot of waxes fall into that group). So far as I can judge he's now after cleaning
up the DCM.
Washing the DCM with caustic to remove the waxy stuff might work but alkaline extractions often give messy emulsions.
For the original extraction of the oils, in general it's better to steam distill out essential oils, not least because water's a very cheap solvent.
OTOH the oils always come over with a lot of water and you will improve the yeild if, in addition to simply separating the oil from the water by
density, you also extract the water layer with a solvent to remove such oil as is dissolved in it. DCM is quite a good choice for this as it's easy to
evaporate off again later.
Oh, also, I wouldn't have refered to the DCM/water azeotrope if it didn't exist and I'm reasonably familliar with the idea of steam stripping for
solvent revovery. I still think it's a weird steam distillation.
I still want to know what this thickening agent/wax that distills below 40C is. Whatever it might be, if it distills over with straight DCM at 39.75C
I suspect it will distill over with the water/ DCM azeotrope at 38.1C so I don't see any advantage to steam distillation to clean up the solvent
(unless the stuff happens to react with water). |
Bad suggestion. In a lab n-alkanes works wonders on waxes. Certain chain lengths are particularly cheap. However, it seems he has limited access to
these sorts of things.
... as for the steam stripping .... try it if you like. It works in industrial applications, and thats good enough for me.
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Ozone
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Errata!
Thanks Unionised! That is correct, CHCl3 will easily give dichlorocarbene (see Hoffmann Isonitrile synthesis); DCM cannot (with this base) do this.
Stronger bases, however, such as Na, will form carbene from DCM; these reactions have a tendency to explode.
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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unionised
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I must be missing something here. XxDaTxX, do you really think it's easier to get hold of DMSO than gasoline/ kerosene/ white spirit/ lighter fluid?
My guess is that, wherever Quince bought the DCM+ waxy stuff from stocked some sort of cheap hydrocabon solvent labeled as "turps substitute" or some
such. DMSO isn't something I have seen for sale OTC except on eBay.
(Quince I realise that it isn't relevant any more because you cleaned the flask with caustic, but I'd be grateful if you would let us know whether you
would find it easier/ cheaper to get DMSO than gasoline or some such.)
I'd still like someone to explain to me why steam distillation will work any better than ordinary distillation for removing waxy stuff from DCM
(unless the stuff reacts with water which I think is unlikely. I'm also open to wild speculation about the nature of this distillable wax. Solids with
significant vapour pressures at 40C are thin on the ground- I'd like to know more.
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Quince
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| Quote: | Originally posted by XxDaTxX
partitioning in DCM. |
Well that's the thing. I've never taken a university chemistry class, so I simply have no idea how to do that, and likely do not have the hardware
for it. On the other hand, I have a Gregar extractor that a retired blower made for me cheaply, so I use what I have and did solvent extraction.
Is there any test I can do on the waxy stuff to try to find out hat it is? I'm not even certain it's wax; it appears to be a bit like a polymer after
the caustic acts on it.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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XxDaTxX
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| Quote: | Originally posted by Quince
| Quote: | Originally posted by XxDaTxX
partitioning in DCM. |
Well that's the thing. I've never taken a university chemistry class, so I simply have no idea how to do that, and likely do not have the hardware
for it. On the other hand, I have a Gregar extractor that a retired blower made for me cheaply, so I use what I have and did solvent extraction.
Is there any test I can do on the waxy stuff to try to find out hat it is? I'm not even certain it's wax; it appears to be a bit like a polymer after
the caustic acts on it. |
Add water/essential oil mix obtained by steam distillation into a seperatory funnel (or any container that dosent dissolve in DCM) and add DCM. Shake
and seperate.
Alternatively, you should go buy a "basic organic chemistry techniques" book off ebay/amazon ..... before you explode your seperatory funnel by adding
to freshly collected distillate and not venting.
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Quince
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I take it the oils mostly end up in the DCM portion? Then I can simply distill off the DCM and no further processing?
[Edited on 11-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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XxDaTxX
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| Quote: | Originally posted by Quince
I take it the oils mostly end up in the DCM portion? Then I can simply distill off the DCM and no further processing?
[Edited on 11-12-2006 by Quince] |
Yes.
| Quote: | Originally posted by unionised
I must be missing something here. XxDaTxX, do you really think it's easier to get hold of DMSO than gasoline/ kerosene/ white spirit/ lighter fluid?
My guess is that, wherever Quince bought the DCM+ waxy stuff from stocked some sort of cheap hydrocabon solvent labeled as "turps substitute" or some
such. DMSO isn't something I have seen for sale OTC except on eBay.
(Quince I realise that it isn't relevant any more because you cleaned the flask with caustic, but I'd be grateful if you would let us know whether you
would find it easier/ cheaper to get DMSO than gasoline or some such.)
I'd still like someone to explain to me why steam distillation will work any better than ordinary distillation for removing waxy stuff from DCM
(unless the stuff reacts with water which I think is unlikely. I'm also open to wild speculation about the nature of this distillable wax. Solids with
significant vapour pressures at 40C are thin on the ground- I'd like to know more. |
I have seen DMSO available from small pharmacies before .... although I thankfully have never had the need to purchase it myself.
I retracted my statement about DMSO dissolving wax ... not that it doesn't but because I cannot say with any degree of certainty because I haven't
tried it. It was a shot in the dark for a, personally, available solvent that has worked in other situations for myself. I have, as of late, had
much success using boiling DMSO to clean out flasks with polymerized gunk that a/b baths wouldn't take out.
I usually leave the chromic to the undergrads who have been bad. Im .... uhh .... allergic to the stuff ..... yeah thats it. =P
[Edited on 11-12-2006 by XxDaTxX]
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Quince
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Steam distillation is underway. Hopefully it will work.
One thing is I don't know when I should stop. Since I'm using the thermometer hole for the steam injection tube, I can't stick a thermometer in the
flask...
[Edit:] Er, deposits are starting to grow at the end of the condenser spout...WTF?!
Looks like ice
[Edited on 11-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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XxDaTxX
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| Quote: | Originally posted by Quince
Steam distillation is underway. Hopefully it will work.
One thing is I don't know when I should stop. Since I'm using the thermometer hole for the steam injection tube, I can't stick a thermometer in the
flask...
[Edit:] Er, deposits are starting to grow at the end of the condenser spout...WTF?!
[Edited on 11-12-2006 by Quince] |
You added some water to your DCM/wax first right?
Hold on ..... you are trying to purify waxes that came over when doing an extraction right? You aren't trying to purify some kind of paint/stripper
methylene chloride mixture you purchased from an orange warehouse right?
[Edited on 11-12-2006 by XxDaTxX]
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Quince
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If you thought it was the former rather than the latter, you're the only one in this thread. Very first sentence in the very first post: "gelling
agent/thickener". Another clue should have been garage chemist's post: "How about buying pure DCM instead of that crap that
obviously cannot be separated into its constituents?"
[Edited on 11-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Quince
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Worked, but yield wasn't good. Quite a bit of the DCM evaporated, even though I was doing everything outside in the cold and the condenser had 5*C
water running through it. In the end the amount of wax was pretty small (a few percent), for all the mess it made.
[Edited on 11-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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XxDaTxX
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| Quote: | Originally posted by Quince
Worked, but yield wasn't good. Quite a bit of the DCM evaporated, even though I was doing everything outside in the cold and the condenser had 5*C
water running through it. In the end the amount of wax was pretty small (a few percent), for all the mess it made.
[Edited on 11-12-2006 by Quince] |
General procedure is centrifugation in low temps, followed by steam distillation. Like i said, it has its pitfalls as far as condensing the vapor and
controlling the feed rate, but with no access to a centrifuge, and limited access to reagents, thats probably the best you can do.
If you could centrifuge beforehand, then the distillate would be pretty much pure.
A fancy schmancy jacket/coil condenser can be had for not much money if you plan on doing this often. I would suggest ordering a short column with
support for packing while you're at it. Just don't look to aldrich or the like unless you are skilled in the art of ankle-grabbing.
Remember, the flow rate of your steam is only a fraction of the flow rate of your DCM, thus the need for extra cooling, and the controllable steam
vent.
[Edited on 11-12-2006 by XxDaTxX]
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Quince
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| Quote: | Originally posted by XxDaTxX
Just don't look to aldrich or the like unless you are skilled in the art of ankle-grabbing. |
I'm not familiar with that euphemism.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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unionised
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You can probably consider yourself lucky. I understand that the idea is something like grab hold of your ankles and prepare to be "taken"  from behind.
Aldrich are not cheap.- Don't get me wrong here, they are very good at their job, and we use there stuff a lot at work. It's just that I'm glad it's
not my money we spend.
[Edited on 11-12-2006 by unionised]
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Maya
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Translation for those not familiar with this fancy chemical terminology:
"Aldrich charges you so much when ordering from them that it feels like you're getting it in the kiester"
Q, sounds like you are overheating your distillation because your flask is hotter than the BP of DCM. Try a water bath at 45 deg or so and a rotovap
or strong stirring with a slow distillation . I'll bet that will work
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unionised
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"Q, sounds like you are overheating your distillation because your flask is hotter than the BP of DCM. Try a water bath at 45 deg or so and a rotovap
or strong stirring with a slow distillation . I'll bet that will work "
Good point Maya, I guess you will be right and if you are it saves me the bother of wondering what this low-boiling wax is and it may save endless
trouble explaining how it might distill a couple of hundred degrees below its boiling point.
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Quince
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Well, they were the cheapest source of KCNS we found for our graphics project.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Maya
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semimicro organic qualitative analysis of your wax , easy to do with standard chems, first year organic lab book will show you which tests to make to
see what your wax is
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unionised
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Forgive me, it's a while since I did first year organic. My best guess is that the wax is a mixture containing celulose ethers, high molecular weight
branched hydrocarbons, quite possibly a few polyalkyl benzene derivatives and some polyethyl/ propyl ene glycols. I could analyse it; but I'd rather
not have to. (Actually, I'm not so sure about that because I'd get paid for doing it if I had to .)
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Quince
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Hmm, I can only offer my body as payment at this time.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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unionised
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Looks like we will have to look at the datasheet.
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Quince
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Aww, you didn't accept my offer. Maya, you tell him dude, tell him how well I can pleasure
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Maya
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I wouldn't know, you guys just think evil thoughts all day
Now go do something productive like learning Org Chem ( as she cracks her whip again )
[Edited on 11-12-2006 by Maya]
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unionised
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( as she cracks her whip again )
Could you do that again please?
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