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Friendlycat
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| Joined: 14 Apr 2005 |
| Posts: 32 |
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1444.78 Points
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re: Purification of denatured alcohol
Sun Sep 25, 2005 12:27 pm |
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What about damage to the flasks? Don't know about you guy's but I love my RBF's. I get upset about the slightest scratch. So I did the 10% NaOH reflux and distillation and got apparently cleaner alcohol, orange goo and a damaged flask.
How hot does the solution have to be for the ketones to react with NaOH. I'll use vacuum but don't want more flask damage! I hate seeing those milky rings on my otherwise perfect vessels. |
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MiNdBaBY
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| Joined: 16 Mar 2005 |
| Posts: 40 |
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2093.46 Points
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Re: re: Purification of denatured alcohol
Sun Sep 25, 2005 12:54 pm |
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| Friendlycat wrote: |
What about damage to the flasks? Don't know about you guy's but I love my RBF's. I get upset about the slightest scratch. So I did the 10% NaOH reflux and distillation and got apparently cleaner alcohol, orange goo and a damaged flask.
How hot does the solution have to be for the ketones to react with NaOH. I'll use vacuum but don't want more flask damage! I hate seeing those milky rings on my otherwise perfect vessels.
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ROFLMAO
Try distilling THF or DCM from OTC sources, lol, both wonderful ways to destroy a flask.. Or even better, producing Benzyl Chloride via refluxing tolly with hypochlorite, where it is damn near IMPOSSIBLE to get the calcium crap out, or better yet production of Nh3 via NaOH & Nh4SO4.
MiNd has found that OTC bottles of wine sold in the 4l/Gallon qty are perfect sources of very inexpensive glassware. These $8-$10 thick walled bottles are superb reflux and distillation flasks and combine well with a OTC single burner/hotplate, a pot just large enough to fit the boiling flask, and an oil bath.
MiNd has moved over to almost always using those specific boiling flasks these days except for anything which MiNd does in too small of scale, otherwise, MiNd has gone through too much lab glass ware to date and lost too many flasks.
The cleaning issue, trying to remove 'sludge' and other crap which are the remnants of many rxns, such as the few MiNd mentioned above, is almost impossible and MiNd has broken a couple flasks trying to clean them, one flask (think it was a 500) MiNd broke just from HOLDing too tight with his hand while trying to clean it..
See my Cl2 production thread for a picture to examplify this.. |
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NS29
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| Joined: 19 Sep 2005 |
| Posts: 10 |
| Location: Taka-Tuka-Land |
336.56 Points
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Re: re: Purification of denatured alcohol
Sun Sep 25, 2005 5:16 pm |
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| MiNdBaBY wrote: |
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Try distilling THF or DCM from OTC sources, lol, both wonderful ways to destroy a flask..
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yikes! what exactly happends to a flask wenn one distills DCM from a DCM/Methanol mix?
i was about to do that tomorrow  |
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Friendlycat
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| Joined: 14 Apr 2005 |
| Posts: 32 |
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1444.78 Points
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re: Purification of denatured alcohol
Tue Sep 27, 2005 4:07 am |
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Wow, I should try lateral thinking more often. Thanks, never thought about using ordinary bottles, which should be fine for alcohol. Sir, I am in your debt.
Regards,
FC |
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Friendlycat
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| Joined: 14 Apr 2005 |
| Posts: 32 |
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1444.78 Points
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re: Purification of denatured alcohol
Tue Sep 27, 2005 4:08 am |
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Wow, I should try lateral thinking more often. Thanks, never thought about using ordinary bottles, which should be fine for alcohol. Sir, I am in your debt.
Regards,
FC |
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bio
Working Bee
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| Joined: 13 Feb 2005 |
| Posts: 236 |
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9718.84 Points
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re: Purification of denatured alcohol
Tue Sep 27, 2005 6:23 am |
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........The cleaning issue, trying to remove 'sludge' and other crap which are the remnants of many rxns, such as the few MiNd mentioned above, is almost impossible and MiNd has broken a couple flasks trying to clean them, one flask (think it was a 500) MiNd broke just from HOLDing too tight with his hand while trying to clean it.. ......
Seems that all the flasks I ever broke also happened while cleaning or attemting to clean off some stubborn residue. For alkali residues conc HCl works somewht but takes days and may even need to be refluxed.
I have a 2L RB that was used with a refluxing solution of GAA nearly saturated with
Na Acetate and the damage was enough to retire it from all except light duty uses.
I've tried for over a year to get this shit off but it seems that it permeated into the glass somewhat.
Is there anyway to recover a flask damaged by acetate or has the glass itself actually been altered? |
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nubee
Master Archiver
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| Joined: 18 Feb 2005 |
| Posts: 214 |
| Location: homeless |
18618.86 Points
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distilling dcm, and cleaning
Thu Oct 06, 2005 1:27 pm |
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| NS29 wrote: |
| MiNdBaBY wrote: |
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Try distilling THF or DCM from OTC sources, lol, both wonderful ways to destroy a flask..
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yikes! what exactly happends to a flask wenn one distills DCM from a DCM/Methanol mix?
i was about to do that tomorrow
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if you've got dcm/methanol , id add a bit more methanol, and if its just dcm, some water, to prevent either from boiling dry...
swim prefers the straight dcm stripper, (now chance of methanol contamination or temp rising), but its more expensive
also watch out as a layer of gunk can form on the top of your liquids, that a stir bar is dropped through (as stiring can help), causes hot liquids to come flying back up and out the still head...
you may end up with some white gunk left behind on the walls of your flask, this can be removed with hot (perhaps acidic) water ...
a swim didnt add the extra buffer liquid and boiled dry, thus having to use conc. sulphuric acid to clean  |
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