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Panache
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| Quote: | Originally posted by Rosco Bodine
Nitroethane could possibly be reduced to ethylamine.
Al amalgam or Al isopropoxide would probably do it.
Metaldehyde and ammonium nitrate would possibly react
giving a nitrate salt which could then be basified to
free the volatile amine. This is not something I have ever seen described
but there is an analogous reaction for methylamine.
These reactions could be hazardous, but manageable.
You would have to distill out the free amine and
absorb it in water.
[Edited on 17-12-2008 by Rosco Bodine] |
Thats how i made it, i remember now. I used the nitrobenzene reduction reactions conditions using Sn/HCl in Vogel Vol 3 but using nitroethane, the
ethylamine distills off from the horrendous reaction matrix at the end quite well. The aqueous solution can then be acidified and the Ethylamine.HCl
crystallised and purified via recrystalisation, then basified using a minimum volume of caustic solution and distilling up a condenser running ~5C
water then further up a NaOh pellet tower condensing the very pure ethylamine finally with ~-10 coolant or better still a dry ice condenser. If i
recall correctly it was some >95% pure via gc. It took a couple of days but at the time was better than waiting for Sigma/Aldrich to ship via the
slow boat (3months). Stores fine in the freezer at -20 with a good ground glass stopper, some silicon grease and an argon blanket. I only made ~50g
this way so scaling it is anyones bet but i think the Sn reaction would be like NYE if it got too big.
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Panache
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Dry Box techniques.
So i'm new to this dry box game. Been doing some reading on it and using it i'm slowly getting the hang of it, as usual practice is about 200 times
more valuable than theory. There are however some simple things which no-one ever seems to give advice on. At the moment there are two questions i
have.
Firstly what is standard protocol for how long you leave the box after you open it to put something into it before it's considered 'dry' again. I am
running argon in the box.
Secondly if i want to filter something that is in the freezer very cold and the crystalls i want to keep dry by the time i get it from the freezer to
the dry box water has condensed a little on the vessel, then waiting for this to 'dry' in the dry box means the solution comes to temperature and the
crystals re-dissolve a little. So its lose-lose, ha! Any tricks?
Maybe i need a freezer room with a dry box within it!!!
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sparkgap
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| Quote: | ...then can this also be true?
N,N'-dimethyl-o-phenylenediamine condenses with ketones and aldehydes to give rise to Schiff bases. |
Best to try, I think, to be sure. Offhand, your diamine seems rather too hindered for me; if it reacts, the enamine ( >C=C-N< and not the imine (>C=N-) will form.
sparky (~_~)
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Klute
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Panache, put your schlenk/flask in a sealed bag or similar with a dessicant inside before putting it in the freezer, then open the bag justbefore
inserting the schlenk into the port, leave it under vacuum a while, and open it up.
I'm not familar enough with glove boxes to give you a detailed procedure. Are you talking of a true glove box, or a home built dry box? With a dry
box, a few hours with CaCl2, eventually followed by an hour or two with KOH or even P2O5 should give you very dry atmospher, more than suitable for
most needs.
Using a glove box, you will need to let is turn overnight to be sure you have minimum oxygen and humidity, we usually have the glow boxes continually
on, even if we don't use them for more than a week, no need of ruining the catalysts for a little argon and the electricity for the vacum pump.
Obviously this might not be an option for an occasional, personal use!
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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Intergalactic_Captain
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Anyone familiar with the Letts Nitrile Synthesis? Ar-COOH + KSCN -> ArCN +CO2 + KSH
http://en.wikipedia.org/wiki/Letts_nitrile_synthesis
Can't seem to find a mechanism, wondering if it would work with indole-3-carboxylic acid.
If you see me running, try to keep up.
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solo
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Letts Nitrile Synthesis
E. A. Letts, Ber. 5, 669 (1872).
Formation of nitriles by heating aromatic carboxylic acids with metal thiocyanates:
G. Krüss, Ber. 17, 1766 (1884); E. E. Reid, Am. Chem. J. 43, 162 (1910); G. D. van Epps, E. E. Reid, J. Am. Chem. Soc. 38, 2120 (1916); D. T. Mowry,
Chem. Rev. 42, 264 (1948); F. Klages, Lehrbuch der organischen Chemie I (Berlin, 1959)
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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brew
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Does anyone know about the reaction conditions for the formation of Ethylenediamine via - and only via - electrolyses. Apparently Glysine as a copper
salt is used and is converted to Ethylendiamine, and also 4-aminobenzoic acid-also as a copper salt is converted to benzidine. The information I have
found for this is far from clear, other than the copper salts of these reagants were used. NO other details, I have looked pretty hard and assuming
that it is something very unpracticle or just plain bullshit. If it isn't then I'd be interested in exploring perhaps the use of copper acetate with
someother reagant containing a carboxy group. ie, AA"S Any help would be appreciated
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not_important
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Sounds like a variation of the Kolbe electrolytic dimerization :
2 RCO2(-1) => R-R + 2CO2
this reaction generally doesn't work well with carboxylic acids that have electron releasing groups alpha to the CO2, alpha amino acids being one
such. This indeed could be a case of a low yield reaction, references to it seem to date from the later 19th and early 20th century - http://tinyurl.com/85ybbs mentions it about half way down the right hand column - when there was a lot of examples of reactions giving a
mishmash of stuff being described as making some particular compound.
The mixed reaction has been suggested a number of times with no success reported, although SFAIK without the use of copper salts.
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Intergalactic_Captain
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solo - Thanks, but I've already followed out all those refs (except the german book) and found nothing of particular use. None of them speculate a
mechanism.
Anyone know if Carolina Biological Supply sells to individuals? Failing that, any larger chemical suppliers that do?
If you see me running, try to keep up.
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Formula409
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Aluminum Triiiodide preparation
1 mol Al turnings (or foil or powder all work well, powder is the quickest closely followed by foil then turnings a distant third) is combind with
1.5mol (note the excess of Al) of Iodine in 1000mL of cyclohexane (exchange solvent as needed but not diethyl ether!). This mix is stirred under
reflux until the red colour has turned to a grey (about 1.5hrs with powder, 2-3 with foil, 4+ with turnngs). At this point the heat is turned off and
the AlI3 in solvent allowed to cool to room tempeature with stirring.
Would Toluene be a suitable substitute in this reaction? What does "AlI3 in solvent" mean? The AlI3 is dissolved? How would it be claimed, surely they
don't expect one to evaporate off 1L of solvent!
Formula409.
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brew
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Thankyou not_important, yes I see what you mean by the amine and its lone pair and its possible effect towards the partially positive charged carboxyl
carbon. This would inhibits its cleavage I'd imagine. I need to think through this stuff rather than just be looking for reactions and yields. It may
be interesting to explore the effects of various pH values - Iso point ect- with such a reaction, and perhaps the effects of copper. Ive read
somewhere about glycine complexing with copper, and it may be worth exploring.
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Klute
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Formula, there has been a post on that exact subject not logn ago, try using the search engine. Basicly, yes AlI3 is dissolved in the solvent (and
yes, they could expect you to evaporat 1L of solvent, it is not uncommon, but they don't here: you directly use the AlI3 in solution). There
were some questiosn about toluene being able to disproportioante in presence of AlI3, even though it might not be a problem, better use something like
hexane.
Read the related thread.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
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transformer
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Does anyone know good solvent system (and maybe an aproximate Rf value) with regards to performing a tlc on phenylacetone?
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DJF90
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@ Formula409: If aluminium powder and iodine powder is mixed as a small pile on a heat proof surface, then direct combination of the elements can bt
achieved by adding a drop of water. The reaction is quite vigorous, and gives off alot of iodine vapour, but a cold surface abouve the reaction
mixture should cause the iodine vapor to solidify, allowing you to recover some of this loss. Iodine is easy to powder using a pestle and mortar (or
some inprovised aparatus) - Aluminium should be used as a powder, but it should still work if you cut Al foil into very small pieces.
My own question: I am currently learning about wagner meerwein rearrangements and am happy in general with the course of things. One thing however
does not make sense. If we take for example neopentyl bromide and force it to react under Sn1 conditions, then there is a 1,2-methyl shift. I am happy
with this.
However the mechanism I have is not particularly revealing, and I cannot quite see how the cyclic transition state is formed (And where is the
positive charge in this transition state? Is it delocalised? I dont understand this.) Can anyone help?
Merry christmas everyone
[Edited on 24-12-2008 by DJF90]
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Picric-A
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This is probably a very simple organic question for some.
Starting from TerePhthalic acid, Benzene-1,4-dicarboxylic acid, Would it be possible to nitrate the acid group comming of the fourth carbon?
If so would i be able to simply nitrate it and hope it goes to the fourth group?
My apologies if this is elementary, my knowledge on reaction mechanisms is very poor.
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Picric-A
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This is probably a very simple organic question for some.
Starting from TerePhthalic acid, Benzene-1,4-dicarboxylic acid, Would it be possible to nitrate the acid group comming of the fourth carbon?
If so would i be able to simply nitrate it and hope it goes to the fourth group?
My apologies if this is elementary, my knowledge on reaction mechanisms is very poor.
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kclo4
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Can the amines on amino acids be oxidized by Potassium Permanganate or Oxone (KHSO5) to nitro groups?
Also, does having the nitro group make it harder to decarboxylate or easier? The NO2 is very electronegative but I'm not to sure if that is even going
to make much of a difference. I think it would make it easier to decarboxylate, but I haven't found any information on it, or on chloroacetic acids
which i think would act similarly
If it is possible, seems like it would be easy to turn some of the smaller amino acids into Nitroacetic acid, and Nitropropionic acid. Might be kind
of useful 
powers gonna go out soon 
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sparkgap
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kclo4:
With regards to oxidizing glycine, do take a look at this. I assume something similar might happen to larger amino acids.
Picric-A:
If you mean nitrating the benzene ring, you might have to resort to very harsh conditions to succeed because the two carboxyl groups
will withdraw electrons from the benzene ring and make it less susceptible to electrophilic attack.
If you mean attaching a nitro group to the carboxyl group... I don't think you can, and I can't seem to find successful examples of such.
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
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texaspete
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Question: Can Bakelite be made by the home chemist?
I've found various threads mentioning that bakelite can be made form formaldehyde and phenol, but no threads describing the process. Wiki says says it
requires high heat and pressure...
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not_important
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Yes, if you are not out for a practical grade but just want to play with the process.
Mixing solutions of formaldehyde and phenol, with a molecular ratio of about 1.5:1, and adding a solution of NaOH to give a pH around 10, then
warming to 60 to 70 C will give a prepolymer. Care must be taken to prevent thermal runaway of the reaction, else it will go too far.
This stage gives a still liquid if syrupy product. It would be mixed with wood flour (fine sawdust) and then heated to 120 to 130 C to complete the
reaction to a thermoset plastic. The pressure was generally used to form or mold the plastic as it was reacting to set, just making small lumps
wouldn't require that. Large amounts tend to overheat in their interior, cracking the piece, so slow heating and applied pressure would be needed for
them.
A few old references. They state that pressure on the order of "50 to 100 lbs/sq-in" give a solid product rather than one containing bubbles or even
being sponge-like. You can also use a bit lower ratio of formaldehyde to phenol, say 1.1:1, and then add a strong solution of HMTA to the resin to
given enough additional formaldehyde to bring the ration up to 1.6:1 or higher. The HMTA decomposing on heating but stable enough at room temperature
that more fluid resins can be prepared for use as coatings and such.
http://books.google.com/books?id=Vn1BAAAAIAAJ&pg=PA585&a...
http://books.google.com/books?id=X7OEAAAAIAAJ&pg=PA211&a...
[Edited on 26-12-2008 by not_important]
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Picric-A
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I was hoping to replace the -OH group with an -NO2 group, not add it on.
I dont see this working either to be honest.
Would it be possible to nitrate Benzoic acid and if so, what percentage of the Nitro group will go to the fourth carbon?
My aim is 4-nitrobenzoic acid by the way
thanks,
[Edited on 26-12-2008 by Picric-A]
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dann2
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May be of some use:
A Bakelite + KClOx propellent.
Making the resol is relatively easy but if you want to make this king of propellent on a regular basis you need some sort of Vacuum pump
+ chamber and heater (inside the vacuum chamber). It is however possible to make a sstisfactory resol without a vacuum system but the resol takes a
lot
longer to cure.
Note Phenol and Formaldehyde are poisonous and this procecure should be carried out in the open. Once the initial reaction is over and the syrupy
stage is reached then the stuff is relatively harmless (apart from flammability).
Method
Add 20g of Phenol and 0.5ml of 40% NaOH solution to 40ml of 37% aqueous Formaldehyde solution (Formalin). Bring to the boil and boil untill the liquid
becomes noticably thicker (typically in the order of 10 minutes). If you stop too soon it will take forever to cure the resin, if you wait too long it
will beocme too
viscous to mix with the oxidizer (like toffee) or even become fully cured in whatever vessel you were boiling it in. You might be able to salvage it
with alcohol.
The resol is removed from the heat and 108g of KClO4 or 125g KClO3 is stirred in. The resultant is poured or pressed into a mold/casing. Try your
utmost
to get rid of bubbles at this stage. The grain is cured by placing
it in an oven at around 50C or so for about 12-24 hours. The temperature is slowly increased untill the resin sets rock hard at a final temperature of
120C or so.
If you increase the temperature too quick big bubbles will form in the grain.. The first cool part is mostly to allow excess water to evaporate., the
actual curing
takes place at the higher temperatures. A resol that has been dried in a vacuum can be cured somewhat faster.
Never tried the above myself BTW.
Dann2
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kclo4
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sparkgap, thanks for the link but it seems to be oxidizing it further then I want.
I was thinking more so of turning glycine into nitroacetic acid. It seems that amines can be turned into NO2 easily with KMnO4 or Oxone and acetone
(or just Oxone if it is an aryl amine) but I think the carboxylic group might interfere with that reaction.
Also, is something like Nitroacetic acid/nitroacetate easier to decarboxylate compared to acetic acid/acetate?
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Picric-A
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KClO4, why not make Nitroacetic acid from nitromethane (if nitroacetic acid is your desired product)
It seems very easy, http://orgprepdaily.wordpress.com/2008/03/10/nitroacetic-aci...
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kclo4
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Not in need of nitroacetic acid, just want to know if the NH2 on amino acids can be turned into NO2 for some other experiments I'd like to try
eventually
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