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ssdd
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Potential uses of Citric Acid
Ok so I recently got my hands onto a fair amount of citric acid. After searching around I couldn't find too many uses for it. I know it can be used in
the production of HMTD, but what else can it be used for?
(I have a particular interest in organic chemistry and plants if any one has anything involving those that would be great.)
Edited title to make it more descriptive. Chemoleo.
[Edited on 25-4-2007 by chemoleo]
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Nicodem
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You can make trialkyl citrates, di(m)ethyl acetone dicarboxylate, aconitic acid anhydride, citrazinic acid and its N-alkyl derivatives and so on...
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12AX7
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(If it's a good grade!), add it to citrus foods. Lemony 
Huh, it occurs to me that "trialkyl citrates" would be a structurally close inverse of triglycerides. Hmm, there are two methylene groups and an
extra hydroxyl in there outside of what would be the closest inverse. *Shrug*
Tim
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ssdd
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It seems to be of a fairly high grade though I am not positive. How would one go about testing the purity of something like that?
I am searching around for some of those suggested compunds, doesn't seem to be much info out there but I'll keep looking. 
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chemoleo
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You can make nicelooking citrate complexes, i.e. ammonium ferrous citrates etc.
If you look around here, there are a number of threads dealing with this.
Also, citric acid can be converted to acetone dicarboxylic acid (again, search), it has multiple uses for a variety of things, including generation of
heterocyclic rings etc.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Nicodem
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You can get the procedure for acetone dicarboxylic acid and its esters at the Org. Synth. server. Citrate esters are used in cheap perfumes and
deodorants so there must be a bunch of patents describing the esterification of citric acid. Similarly you can find a bunch of patents on aconitic
acid anhydride and citrazinic acid synthesis.
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ssdd
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On the MSDS sheet for citric acid it said that when mixed with a metal nitrate that the mix becomes rather unstabe and is prone to explosion.  Has anyone ever had experience with this or tried it?
I'm still looking around for the makings of diffrent citrates etc.. Ill post if I find anything good.
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Nicodem
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Using MSDS's as a source of data for chemical properties is plain stupid. These things are not even compiled by true chemists anyway. Besides many
organic compounds become "rather instable" when mixed with metal nitrates. It is just a mater of definition of what "rather instable" stands for.
PS: Have you never made any mixtures of sugar and KNO3? Well, that is just about it.
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Mr. Wizard
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| Quote: | Originally posted by Nicodem
Using MSDS's as a source of data for chemical properties is plain stupid. These things are not even compiled by true chemists anyway. Besides many
organic compounds become "rather instable" when mixed with metal nitrates. It is just a mater of definition of what "rather instable" stands for.
PS: Have you never made any mixtures of sugar and KNO3? Well, that is just about it. |
I think chemists and engineers have input into the compilation of data on the MSDS. It's made to be a rough reference for worst case scenarios when
tanker loads or truck loads of material are involved.
Your example of sugar and KNO3 is a good one.
This kind of 'common knowledge' among chemists is not readily apparent to firefighting and emergency response crews who would be using the MSDS
information. They are usually not well informed about this type of thing. Before you dismiss the MSDS sheets, remember that many of the references
are gleaned from hard learned experience and real world experience at high cost.
It is made to be an interface between the technically knowledgeable and the people who actually have to deal with the accidents in the real world. I
would be willing to bet you would be very glad to look at one before you approached a railroad tank car pile-up, with a variety of unfamiliar
chemicals.
Just because you aren't a chemist doesn't make you stupid.
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Nicodem
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I agree about the use of MSDS info in safety and emergency cases, but not when it comes to chemical properties. Like you said: "It's made to be a
rough reference for worst case scenarios when tanker loads or truck loads of material are involved."
As such it can only be a source of disinformation to the chemists. Chemical properties are not worst case scenarios, but everyday scenarios. This
however does not mean that MSDS are an extremely important source of information for the non-chemists who mainly deal with non everyday scenarios. But
obviously many members here still don't know the difference as I often see this idea of using MSDS instead laboratory handbooks as a source of info
about chemical properties.
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Sauron
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Citric acid to acetonedicarboxylic acid and its esters is done with fuming sulfuric acid (oleum). The original publication by Pechmann in Ber. (1884)
employs concentrated sulfuric acid, but it was the same author who introduced the use of oleum somewhat later. I am getting the original paper
translated so we can see how yields compare. Obviously conc H2SO4 would be much more convenient for just about any of us. Fuming sulfuric is bloody
expensive.
The free acid is unstable.
The esters are stable is carefully washed free of sulfuric acid traces.
Acetonedicarboxylic anhydride is also stable, and a rather interesting compound.
The most famous uses of these compounds is in Robinson type Mannich condensations to construct the tropinone bicyclic system.
[
[Edited on 27-4-2007 by Sauron]
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Axt
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| Quote: | Originally posted by Sauron
Citric acid to acetonedicarboxylic acid and its esters is done with fuming sulfuric acid (oleum). The original publication by Pechmann in Ber. (1884)
employs concentrated sulfuric acid, but it was the same author who introduced the use of oleum somewhat later. I am getting the original paper
translated so we can see how yields compare. Obviously conc H2SO4 would be much more convenient for just about any of us. Fuming sulfuric is bloody
expensive.
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I've uploaded the original paper here http://www.sciencemadness.org/talk/viewthread.php?tid=2969 though sadly yields were not stated, nor was the synthesis detailed. I tried it once
with concentrated H2SO4 though yields on this attempt were poor.
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woelen
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Citric acid can also be used in Bhelousov-Zabotinsky type of oscillating reactions. Usually these are carried out with malonic acid (which is hard to
obtain), but citric acid can also be used instead. The only drawback of using citric acid is that the solution becomes turbid with this and some oily
compound is formed, while with malonic acid, the solutions remains clear. Hence, with malonic acid, the result is more visually pleasing.
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Sauron
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@Axt,
Thanks for the input. Yes I know yields with oleum are very good (90+%) while those with conc H2SO4 are not so good. However, oleum costs me a lot of
money (65% fuming sulfuric from Merck, about $900/L, admittedly 2 Kg but even so.)
I have two liters of the 65% Merck product but I'd rather keep it for a more significant project.
How bad are the yields? Even if only 20-30% I'd still rather squander (cheap) citric acid and (cheap) conc sulfuric. The conversion to the ester is
also very lossy. I forget how the conversion to the anhydride goes - maybe better maybe not.
I know the citric acid needs to be dried. I have a drying oven, etc. so this is not an issue.
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Axt
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| Quote: | Originally posted by Sauron
How bad are the yields? |
The first post in that thread shows what I done, thus from 50g citric acid (presumably monohydrate, bought from grocery store) yielded 12g ADCA though
this was only press dried as I had no reason to free it from the H2SO4, so a good portion of that was the residual acid. It was a one off attempt
following no published procedure so it could well be improved upon.
Gee thats expensive for oleum though, 'bout 3.5x more then it is here (Australia) for the same Merk 65% fumin' H2SO4. Though even $260ish per litre
seems way too much.
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Sauron
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It was 65,000 Thai baht for 2 liters of the 65% product.
Now I figure the dealer clipped me for a good 100% markup, as I discovered on another purchase later. So perhaps if I bought it today from a different
reseller who only clips me for 50% or so you could knock 25% off those numbers.
And 1 liter of 65% can be dilted with conc H2SO4 to more than 2 L of 30% or 3 L of 20% oleum. That starts to be a bit less insane although the
dilution process is not for the faint of heart, a lot of heat is evolved. So it must be done slowly w/stirring.'
Anyway let's see, you started with 50 g citric which you did not dry and you got a crude yield of 12 g ADA which is properly isolated might have been
9 g really.
That's not really bad. The Org Syn process starts w/700g dried citric acid and gives about 500 g of the purified ADA. But that's with oleum and yours
is with acid so cheap it may as well be free.
Thanks, that's very useful.
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ssdd
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Ok so I was bored today in my chem class and had some time. So not really having much in mind I tried the Citric Acid/Nitrate mix.
I knew going into it as was warned it wouldn't be anything to fancy.
The first one I ran was Citric Acid and Cadmium Nitrate - Cd(NO3)2
I tried a match lighting which gave nothing, and then a Mg strip with no results. As a last resort I put the burner directly on it. It gave off a
yellow red smoke (this was done in a fume hood) and stained the ceramic dish green. I couldnt get it to self sustain due to the fact that it was
hydrated Cadmium Nitrate (I missed that part on the bottle.) 
I ran a second experiment using Potassium Nitrate. This one worked out much better, but still needed the burner to light it. Once light it self
sustained and bubbled, blowing off alot of black smoke. It burnt with a red flame with small amounts of purple (potassium I guess) in it. There was a
fair amount of black residue left behind.
I know not to many are interested with this, but if anyone has the equation for whats going on that would be great...
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DeAdFX
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What were your weight ratios for Citric acid and KNO3? Prehaps it might burn with less residue if your change the ratio a bit?
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Nicodem
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| Quote: | Originally posted by ssdd
The first one I ran was Citric Acid and Cadmium Nitrate - Cd(NO3)2 |
Cadmium nitrate! My god! Think of the nature. Ecology and all! I don't mind if you ruin your health, but think green.
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Sauron
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The conversion of acetonedicarboxylic acid to its cyclic anhydride (sketched above) is by treatment with acetic anhydride. I suspect that phthaloyl
chloride will do the same. Oxalyl chloride too. However, those are by analogy whereas the Ac2O method is a lit. procedure and goes in 84% yield.
The anhydride is then used to prepare the monomethyl ester which is preferred in the classical Mannich condensation to various naturally occuring
tropinone systems.
That mono-esterification is a quantitative yield according to the lit.
Seems to me that the acid could be monoesterified directly by modifying the Org.Syn. prep of the di-ester.
Or, rhw di-ester could be half-saponified to the mono ester.
But maybe those procedures would give mixtures not easily seperated and yields might suffer. In any case there would be little advantage in terms of
time and labor.
For about 30 years I have been reading about this stuff in connection with synthesis of 2-CMT and thus the ecgonines and a passel of diastereomeric
cocaines. This subject was well covered on Rhodium, q.v. if interested but in no wise can this compete with the economics of the natural product so it
is quite academic and the stereochemistry is pretty daunting. The resolution requires the unnatural isomer of tartaric acid, which is bloody expensive
last time I looked. So, while a very pretty synthesis, I'd advise anyone interested to hone their skills on pseudopelletierine which will be
frustrating enough but won't get you tossed in jail. Not an easy prep.
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ssdd
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| Quote: |
What were your weight ratios for Citric acid and KNO3? Prehaps it might burn with less residue if your change the ratio a bit? |
I ran it at a 50/50 ratio yesterday just for the sake of saving some time. But after running it in a equation solver I see that I should run it at
KNO3 - 606g Citric - 384g or about 2/1.5.
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Nicodem
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Citric acid monohydrate is not appropriate as combustion fuel for such mixes. Actually it is one of the worst choices. Being a monohydrate the
evaporating water takes a lot of enthalpy while 3 out of its 6 carbons are already nearly fully oxidized (the COOH groups) so they are nothing but
dead weight inhibiting the propagation of the combustion. You should try with charcoal. That works better and if you add a tiny bit of sulfur as well
you have the good old gun powder.
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ssdd
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Ok that makes the slowness of reaction rate make more sense.
I have done alot of work with charcoal and metal based powders, I just thought this this would be something a little diffrent.
The acetonedicarboxylic acid sounds like it could be fun to try, I may give that a run later this week.
Thanks for the info.
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Nicodem
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| Quote: | Originally posted by ssdd
The acetonedicarboxylic acid sounds like it could be fun to try, I may give that a run later this week. |
Beter start with something simple as citrazinic acid. If you have no experience in preparative organic chemistry, I don't think the preparation of
acetonedicarboxylic acid and its esters is something to start with.
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ssdd
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| Quote: |
Beter start with something simple as citrazinic acid. If you have no experience in preparative organic chemistry, I don't think the preparation of
acetonedicarboxylic acid and its esters is something to start with
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Ok, but after some searching around all over the place, I can not find a single drop of information as to how to make citrazinic acid. There seems to
be nothing on orgsyn or on the forums. If anyone can give me a link to a page with info or tell me a good method it would be greatly apprechiated.
Also: What are some possible uses for this?
[Edited on 1-5-2007 by ssdd]
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