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panziandi
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I'd expect an explosion or similar, with copious evolution of NOx, ethyl and methyl chlorides (resulting from C-C cleavage which often results from
excessive oxidations), along with the obvious acetic acid and likely CO2. Oh and don't forget a dead or injured chemist and general chaos! 
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Formatik
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I expected a general oxidation at the least. An explosion at worst, possibly with large amounts. Some website I've found claims an alkyl nitrate is
produced, with NO2 fumes these can oxidize violently:
| Quote: | | Aqua regia is extremely corrosive. It must never be allowed to come in contact with ethanol or other alcohols as it forms alkyl nitrates, which may
decompose violently after an unpredictable induction period of a few seconds to many hours. |
http://www.chem.monash.edu.au/safety/safety-manual/
But I'm wondering if something else may be produced on the side, e.g. diazoethoxane or EtClO, both around as dangerous as NCl3.
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chemrox
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dry ethanol in condensation reax
I'm reacting an ester with an aromtic amine. I don't think it would help to be more specific in this case. The solvent called for is ethanol and the
resultant will be a diethyl ketal as an intermediate. The short question is, how "dry" is dry in this case? Can I use the dry ethanol I have out of
the bottle or should I dry it further? CaO distillation?
Thanks,
CRX
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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chemrox
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text on zeolites
To quoate my friend Klute, "who really uses them?" I'm looking for a text or article that covers making modified zeolites for synthetic applications.
(should I have posted this in refs?)
Thanks,
CRX
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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crazyboy
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I have a quick distillation question. How would I extract a chemical with a known boiling point from several with unknown boiling point.
EX: I have window cleaner which contains an unknown percent of (X) say between 5-15% chemical (X) boils at 170C
To isolate (X) I would heat it below 170 and discard all that comes over then heat to 170 save all that comes over and what comes over at 170 is
fairly pure (X) right?
I get the theory but are there any technical issues or problems with this?
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sparkgap
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Well, how sure are you that your known compound won't form an azeotrope with the other components of your mix? Try finding the MSDS of your window
cleaner so you don't have to do much guesswork.
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
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497
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Just a quick question that I haven't haven't found the answer to. Maybe I'm not looking in the right place.
Is there a reaction between N2O and N2O4, especially in high pressure situations? It seems so simple, you would think it wouldn't be hard to find.
Every search is swamped with stuff about manufacture of N2O or HNO3, etc. Thanks.
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Ephoton
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I would love to know about drying ethylacetate for use in nitrile condensation. I have no access to phosphorous pentoxide is there another way.
also is azeotropicaly formed ethoxide ok for the catylist.
thanx for any help.
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solo
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In an aromatic aldehyde , is there a way to remove the aldehyde end group and substitute for an amine group? I have been looking, but most of the
reactions will leave the carbon and add the amine ........solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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Picric-A
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I need to make some Al2O3 for use as a catalyst.
What is the best way i go about doing this?
I thought-
Dehydration of Al(OH)3
Decomposition of Al(NO3)3
Melt Al metal and keep it molten for a while until sufficient oxide builds up. Any ideas on how to seperate the Al/Al2O3 mix?
Thanks!
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Sauron
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Hopefully this is a short question. I am frustrated trying to find lit. on the preparation of ethyl (or methyl) 3-aminocrotonate, aka ethyl
beta-aminocrotonate, the enamine which I think forms from acetoacetic ester and NH3.
It is commercially available, but costly compared to ethyl acetoacetate (8X or so).
If someone could point me at a prep, I'd be grateful.
Not in Merck
Not in Org Syn
Not in ACS Journals that I can see (via SE)
Google unhelpful
I am off to try RSC now.
No luck
I guess saturating ethyl or methyl acetoacetate in benzene or toluene and azeotroping out the water with a Dean-Stark trap ought to do it.
[Edited on 23-10-2008 by Sauron]
Sic gorgeamus a los subjectatus nunc.
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chemrox
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Have you gone to Beilsteins?
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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sonogashira
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The sigma-aldrich website gives this beilstein reference:
Beil. 3,II,414
I don't have access to it though
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12AX7
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| Quote: | Originally posted by Picric-A
I need to make some Al2O3 for use as a catalyst.
What is the best way i go about doing this?
I thought-
Dehydration of Al(OH)3
Decomposition of Al(NO3)3
Melt Al metal and keep it molten for a while until sufficient oxide builds up. Any ideas on how to seperate the Al/Al2O3 mix?
Thanks! |
Molten aluminum (i.e., at ca. 600-700°C) with adherent oxides, generally known as white dross, breaks up under a molten salt flux to yield a gray
powdery product, which is probably not very active. Metal yield is quite good however, so it's a good plan if you wish to reclaim your aluminum.
(This includes pop cans, which produce considerable oxides when melted in air.)
Brauer (see the SMDB library) suggests dehydrating hydrargyllite at 500-600°C. Hydrargyllite is precipitated from a concentrated sodium aluminate
solution by leaving it to rest for several weeks. The precipitate is washed until no alkalinity remains.
Tim
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kclo4
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After thinking about your question and trying to find a way to make it I'm now curious if it could be made by acidifying Sodium Aluminate?
"Pure sodium aluminate (anhydrous) is a white crystalline solid having a formula variously given as NaAlO2, Na2O · Al2O3, or Na2Al2O4."
Given that it is written as Na2O · Al2O3 when anhydrous you'd think adding HCl would produce H2O and Al2O3 instead of the Oxide. Much like how Sodium
Silicate( Na2SiO3) forms Silicon Dioxide. Of course, they are completely different elements, but may still apply.
Na2Al2O4 + 2 HCl = 2NaCl + Al2O3 + H2O.
for some reason I doubt this, but I guess its possible since the reaction doesn't even contain enough water to produce Al(OH)3. It may form, but I
believe Al2O3 would also form.
However, if this is for a catalyst why not produce and use Silica gel instead?
NaOH and Sand react really easily with a propane torch in a Iron crucible. Then just acidify and allow it to fall out of solution.
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Sauron
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I have not looked in Beilstein because (1) I have no online access and (2) the reference is to the second supplement not the Haptwerk, and I have only
the Haptwerk.
Anyway I finally found references in a J Org Chem paper, they cited a Michaelis paper in Annalen 366 and a paper by Arthur Cope and coworker in JACK
67. As I surmised the 3-aminoester is prepared by bubbling anhydrous ammonia into neat acetoacetic ester for 5 hours (on a 100 g basis). In first hour
temp rises to 40 C and then further rise is checked with cooling and held at 35-40 C. Then 100 ml Et2O is added, and the water formed in the reaction
is seperated and discarded. The ether is rotavaped off and the residue distilled in vacuo. Yield 90%.
I will post the Cope paper in my CCl3Br thread for anyone who wants the physical constants etc.
In most cases JACS and JOC papers referring to this reagent just say "purchased from such and so" which is highly annoying when one is looking for
preparative details...
[Edited on 23-10-2008 by Sauron]
Sic gorgeamus a los subjectatus nunc.
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not_important
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| Quote: | Originally posted by kclo4
After thinking about your question and trying to find a way to make it I'm now curious if it could be made by acidifying Sodium Aluminate?
"Pure sodium aluminate (anhydrous) is a white crystalline solid having a formula variously given as NaAlO2, Na2O · Al2O3, or Na2Al2O4."...
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Two different sources/forms of saodium aluminate. The one you reference is the dry form from high temperature reaction, the previous one uses an
aqueous solution from reacting concentrated NaOH with Al(OH)3, AlO(OH), or crude open structure Al2O3.
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Picric-A
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I am mostly using the Al2O3 for cracking of hydrocarbons and i wasnt sure if SiO2 would work for this aswel.
The molten aluminium is a good way to get oxide but the oxide is hold together by molten aluminium so is difficult to get the plain oxide.
I will try the Sodium aluminate method, I will make it by dissolving Al in dilute NaOH till neutral then try acidify. I am away form my lab tho so i
cant do it until around sunday,
thanks for the help!
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not_important
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You'll want fairly strong NaOH, and CO2 is acid enough to force Al(OH)3 out of the aluminate solution.
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Klute
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STEVE: 10-15 HCl or 20% H2SO4 and several hours of reflux works very well for cleaving primary amides. Adding a bit of methanol to mix layers helps.
This also works with secondary amides to some extent (depending on the substituants, might need longer reflux)
CHEMROX: I would use absolute EtOH, if you have a freshly opened bottle it should fine, otherwise just keep the EtOH over molecular seives overnight
and transfert by canula to avoid contact with atmospher. It doesn't need to rigorously dry, but the dryer the better. Traces of ethoxide could work as
a catalyst if this is an aminolysis, but yu cn't dry the EtOH with sodium or NaH as the formed NaOh will cause some hydrolysis of the ester.
SOLO: Do you mean replacing Ar-CHO by Ar-NH2? The only I see if forming amide, and doing a hofman degradation... Not the best yields I guess.
EPHOTON: Have you acces to Molecualr seives? They should do the trick after purifying the ester according to conventional way. CaO could work out
well enough if your ester has been efficiently pre-dried. I doubt azeotropically formed ethoxide (you well refluxing ethanol, NaOh and toluene I
suppose?) will work, as even traces of NaOH will cleave the ester, form water that forms more NaOh, which saponifies more ethoxide, etc. Only freshly
prepared alkoxide from sodium or NaH would worked here IMHO, even solid NaOEt woudn't be a good option. If you really can't acces any of these two,
you might want to look into magnesium ethoxide, either used directly (if possible, check the litt, as alkali and alkali-earth alkoxides have in some
case very different properties), or used to make sodium ethoxide via metathesis.
[Edited on 23-10-2008 by Klute]
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
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TDCFMOG
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I have a Kimax beaker with a "bump" on the rim.
It doesn't look like there is a bubble inside it, but I'm not sure if it's safe to heat it on a good hotplate.
Should it be fine or should I play it safe and just use it for transferring liquids?
"All things are poison and nothing is without poison, only the dose permits something not to be poisonous." -Paracelsus
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Picric-A
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Good brands like pex, Kimax ect... use UV to make sure there are no bubbles in the beakers/test tubes ect...
I doubt this is a gas bubble probably just a little exess glass that was left over in the forming process.
If in doubt get a small hammer and lightly tap on the bubble. If it was air it would break easily.
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Ephoton
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thanx klute .
I guess exust valves are the go then as we can all get them.
why do they only reference boric anhydride as a drying agent for formic acid.
surely it could be used for other substances.
ps
tapping glass with a hammer is not wise.
just use the glass with something harmless for the first few times to test it.
[Edited on 25-10-2008 by Ephoton]
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kclo4
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They probably state to use Boric anhydride; B2O3, for drying Formic acid because other compounds react or decompose formic acid. While B2O3 chemically
reacts with the water, making it impossible for it to get sucked up by the formic acid again.
I'm sure other substances can dry it, but at the moment I can't think of any decent ones and Boric acid is easy available and can be turned into B2O3
with out much hassle by simply heating it.
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Ephoton
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thanx for the response kclo4.
what I ment was why do we never hear of boric anhydride being used for other things.
for instance surely it could be used to aquire glaciel acetic acid.
or even dry ethyl acetate.
[Edited on 26-10-2008 by Ephoton]
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