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Sauron
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You can easily check the same sources I did.
Acros tech data sheets - shall I attach them?
Merck Index 12th Edition, monographs for oxalic acid and malonic acid.
Malonic acid 1400 g/L H2O 20 C
Oxalic acid (anhydrous) 90 g/ L H2O 20 C.
That's c. 15X more solubility in the commonest solvent we have at room temperature.
So, identification and seperation are EASY. It doesn't get any easier.
Merck merely restates the identical difference in solubility in a slightly different way.
1 g malonic acid dissolves in 0.6 ml water. In other words, water dossolves 1.4X its own weight of malonic acid. How much does a liter of water
weigh? 1000 g by definition. So, how much malonic acid will dissolve in that liter at 20 C? 1400 g.
I believe Merck Index is on the Reference forum in digital form. I am using the hardback I bought in mid 90s. For a long time that and an elderly
Aldrich were the only chemical references I had here.
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pantone159
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| Quote: | Originally posted by Sauron
Acros tech data sheets - shall I attach them?
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Sure, if it is convenient. Can I find these online? I wasn't disbelieving you, btw, those numbers just sounded too good to be true. My CRC merely
describes both as soluble in water. Separation from unreacted malic acid may be an issue as well.
| Quote: |
I believe Merck Index is on the Reference forum in digital form.
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I didn't know that, I'll look for it. Otherwise I'll head to the library to read the dead-tree version. Thanks.
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Sauron
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http://www.acros.be
is website of Acros Organics. In the Catalong Search field just enter "amlonic acid" and the page will come up. In upper right there's an adove
acrobat PDF icon, click on that and you get the page in PDF rather than HTML, right click on that and save it to your hard disk. Repeat for exalic
acid.
I did not look up malic acid.
As mentioned I think you can download the entire Merck Index from rapidshare, there are links on the Reference forum. I think so. I did not look at
them because I have the book already on my shelf.
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Sauron
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NOTE that the hydrated form of oxalic acid may have different solubility than the anhydrous acid.
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pantone159
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| Quote: | Originally posted by Sauron
NOTE that the hydrated form of oxalic acid may have different solubility than the anhydrous acid. |
The dihydrate has solubility 138 g/L at 20 C, which is still plenty different to separate them.
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Sauron
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Yes, lower than malonic acid by an order of magnitude.
This happy situation does not always occur, you know? But in this case, it's very very simple and easy.
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jimmyboy
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heck - get the oscillating kit - 10 bucks for 5 grams of malonic.. easy.. haha of course that would be cheating and you wouldnt learn anything 
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pantone159
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Decarboxylation of oxaloacetic acid
Note: The decarboxylation of the beta-keto acid formed by oxidizing does NOT yield malonic acid, but rather pyruvic acid.
Malic acid, HOOC-CH2-CHOH-COOH, is first oxidized to the keto-acid oxaloacetic acid, HOOC-CH2-C(=O)-COOH.
This will decarboxylate easily. BUT, it doesn't lose the carbon we want. The leftmost carbon is the one that is at the right position for
decarboxylation, not the rightmost one. So, decarboxylation instead yields pyruvic acid, CH3-C(=O)-COOH.
(FWIW, Wikipedia states the same thing.)
If we want to get from oxaloacetic acid to malonic acid, we need to get that other end carbon to leave. I think this really may require KMnO4, which
can chop up the carbon chain, rather than other oxidants which will go no further than the keto-acid, and all we can get from there is pyruvic acid.
PS - I have made some tries oxidizing malic acid with KMnO4. The major product seems to be a colorless liquid, with an odor I would describe as
'soapy'. Possibly this could be pyruvic acid, but I don't know. I do have some solid crystals in the product, however. The liquid is evaporating
slowly (while standing at RT) and I might even get some reasonable crystals I can try to analyze. I intend to post details, but I haven't got my
write-up into shape yet. My workup needs improvement as well.
PPS - I finally got to the dead-tree library to look up the Fieser reference that Magpie gave. It does say that the process goes through the
keto-acid, but doesn't discuss how one gets from there to malonic acid.
[Edited on 16-2-2007 by pantone159]
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pantone159
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1,3-propanediol, aka "Bio-PDO"
It occurs to me that 1,3-propanediol, HO-CH2-CH2-CH2-OH, aka "Trimethylene glycol" ought to be a very suitable precursor for malonic acid. Oxidize
the two primary alcohol groups to acids by any of the well-developed methods, and one should have malonic acid.
So, where to get 1,3-propanediol? It currently does not seem to be common (a search of my usual sources did not list it for sale anywhere. Aldrich
does list it, $60 for 500 g, but I can't get it there.) "Propylene glycol", 1,2-propanediol OTOH is widely available, cheap, and not suitable for
malonic acid synthesis. (The names of these compounds seem to be used somewhat inconsistently, beware.)
This may soon change. DuPont apparently has just built a plant to produce 1,3-propanediol from corn, with the brand name "Bio-PDO". The first
commercial shipments was just under 3 months ago. The following press release is full of platitudes about 'non-petroleum, bio, renewable' but I
personally just care about moving that pesky OH group to the end.
http://news.thomasnet.com/companystory/500722
The material will be branded "Zemea" for personal-care uses, e.g. cosmetics, which are likely to be a good OTC source, once the stuff becomes
available.
Also see the Wikipedia page:
http://en.wikipedia.org/wiki/1,3-Propanediol
EDIT: I just re-read this thread from the start, and noticed the previous talk about the 1,3-diol, which I had forgot about.
[Edited on 19-2-2007 by pantone159]
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unionised
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Potentialy interesting stuff, though I had to smile at this bit of their site.
"Tate & Lyle uses innovative technology to transform corn, wheat and sugar into value-added ingredients ....
In the last decade, Tate & Lyle established fermentation as a core technological competency and is now one of the world's major fermentation
producers with 17 fermentation plants on four continents. In addition to Bio- PDO(TM), its portfolio includes citric acid, biogums ... and both fuel
grade and potable ethanol."
"Inovative technology" seems to include making rum.
[Edited on 18-2-2007 by unionised]
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not_important
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As it is a new year, I will suggest a 'new' method.
The polyunsaturated fatty acids linoleic and linolenic have respectively one and two =CH-CH2-CH= groupings in them. Treatment with ozone, followed
by workup undex mild oxidising conditions, or just treatment with oxidisers under controlled conditions, will yield mixtures of mono- and di-
carboxylic acids.
These acids are propionic, caproic, malonic, and azelaic - HO3C(CH2)7CO2H
Oleic acid yields perargonic - CH3(CH2)7CO2H - and azelaic.
That is somewhat of a mess, but still not too difficult to separate out. Raw (unboiled) linseed oil is roughly 5% oleic, 60% linoleic, and 25%
linolenic. Note that is the unboiled oil, not the more common boiled; at a higher price the edible form can be purchased as flax or flaxseed oil.
The weight percentage yield is terrible, but in some location linseed oil can be had quite cheaply. Using ozone to accomplish the first stage of
oxidation reduces the cost in oxidisers.
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Sandmeyer
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| Quote: | Originally posted by Sauron
I think anyone competent would recognize that adding a nitrile to mineral acid might release HCN and therefore, this is a procedure to be done in a
GOOD HOOD. ClCN less likely but same caution. GOOD HOOD. If you were to attempt this on a larger scale I would say GOOD HOOD, SCBA, and CAUSTIC
SCRUBBER, the oversize scrubber interposed between the reaction flask and the hood exhaust. |
Nonsense. Hydrolysis of the nitrile could happen, then if heating is continued the CO2 and not HCN is evolved as a result of decarboxylation.
| Quote: | Originally posted by not_important
As it is a new year, I will suggest a 'new' method.
The polyunsaturated fatty acids linoleic and linolenic have respectively one and two =CH-CH2-CH= groupings in them. Treatment with ozone, followed
by workup undex mild oxidising conditions, or just treatment with oxidisers under controlled conditions, will yield mixtures of mono- and di-
carboxylic acids.
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That sounds like an impractical idea.
[Edited on 18-2-2007 by Sandmeyer]
[Edited on 18-2-2007 by Sandmeyer]
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tr41414
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The oxidation of double bonds could be done with acidic CuO, which would make the process quite cheap...
Another thing that comes to my mind for synthesising malonic acid is oxidation of citric acid.
Using hot H2O2(?) http://jxb.oxfordjournals.org/cgi/reprint/4/2/129.pdf Could anyone please fetch the ref?
Also would it be possible to react trichloroethylene with cyanide and then hydrolyse it (or maybe using HgSO4 for hydrolysis to make it more
practical)?
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tr41414
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The article uses 100% H2O2, so that is not really useful, and it also seems that malonic is readily decomposed in rxn 
I might give the CuO oxidation of oil a try  I guess the resulting mess could be
"purified" by forming esters and distilling them...
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Aqua-regia
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The synthesis of malonic acid:
http://www.versuchschemie.de/htopic,10447,.html
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pantone159
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| Quote: | Originally posted by tr41414
The article uses 100% H2O2, so that is not really useful, and it also seems that malonic is readily decomposed in rxn
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Actually it said '100 vol.' which I think is different from 100% (H2O2 has some special concentration units which are often used and I am not really
up on.) It did say:
| Quote: | | very low final yield of malonic acid |
and didn't give much detail for the citric-to-malonic oxidation, so I also concluded that this procedure was not useful, too bad.
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garage chemist
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May I suggest buying some ethyl cyanoacetate and hydrolysing that with NaOH (free malonic acid decarboxylates upon boiling of the aqueous solution, so
alkaline hydrolysis has to be used)?
Ethyl cyanoacetate is seriously cheap, it would actually cost less to make malonic acid this way than to buy it.
And ethyl cyanoacetate isnt a regulated chemical, I think.
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tr41414
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I wrongly assumed that 100 vol. = 100 vol % (it actually corresponds to volume of O2 released by volume of peroxide), so it is around the usually
available 30%.
Also the article mentions decomposition of malonic to acetic acid, which might be affected by adding some base...
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benzylchloride1
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Has any one tried the haloform reaction on 2,4-pentadione? This reaction should produce sodium malonate and chloroform. What would be the best method
to isolate the malonic acid out of the reaction mixture?
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Nicodem
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A haloform reaction on 2,4-pentadione (acetylacetone) would result in 3,3-dihalogenation which upon cleavage with hydroxide gives acetic acid (and
chloroform). See the mechanism of the haloform reaction:
http://www.organic-chemistry.org/namedreactions/haloform-rea...
http://en.wikipedia.org/wiki/Haloform_reaction
http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch18/ch18-3...
As you can see the haloform reaction is based on base catalyzed enolization and subsequent halogenation. Therefore, there is no way for the terminal
methyls of acetylacetone to get involved in the halogenation steps.
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PHILOU Zrealone
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Hydrolyse of speudocarboxylic groups....in basic or acidic media.
Thus nitriles, amides, esters, anhydrides, acid chlorides, alfa trichloromethylcetones, trichloromethyl hydrocarbons can be precursors
-CN --> -CO-NH2 --> -CO2NH4 --> -CO2H + NH4(+)
-CO2-R --> -CO2H + R-OH
R-CO-O-CO-R --> 2R-CO2H
-CO-CCl3 --> -CO2H + HCCl3
-CCl3 --> -CO-Cl +2HCl –> -CO2H +3 HCl
(trichloromethyl hydrocarbons are related to orthoformiates and can be seen as a transient trihydroxymethyl group...-CCl3 --> -C(OH)3 --> -CO2H
+ H2O)
As a side note the following known reaction on refluxing:
Cl2C=CHCl + H2SO4 (H2O) --> ClCH2-CO2H + 2 HCl
This goes maybe via H2O addition and then HCl elimination and ceto-enol equilibration…and finally hydrolysis of the resulting acid chloride…
Cl2C=CHCl + H2O --> Cl2CH-CHCl(OH) --> ClHC=CCl(OH) + HCl <----> ClCH2-CO-Cl --> ClCH2-CO2H + HCl
As a conclusion: the following compounds could be used
CCl3-CH2-CCl3
CCl2=CH-CCl3
CCl3-CH2-CN
CCl3-CO-CH2-CO-CCl3
CCl3-CO-CH2-CCl3
…
[Edited on 5-2-2008 by PHILOU Zrealone]
[Edited on 5-2-2008 by PHILOU Zrealone]
[Edited on 5-2-2008 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
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Jamjar
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A haloform reaction on ethyl acetoacetate should produce disodium malonate and chloroform?
http://en.wikipedia.org/wiki/Ethyl_acetoacetate
"Ethyl acetoacetate may be prepared via the Claisen condensation of ethyl acetate. Two moles of ethyl acetate condense to form one mole each of ethyl
acetoacetate and ethanol."
Regarding Acetoacetate instability
http://en.wikipedia.org/wiki/Acetoacetate
"The acid form has a half-life of 140 minutes at 37º C in water, whereas the basic form (the anion) has a half-life of 130 hours."
I'm a beginner so I could be talking out of my ass.
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Nicodem
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Two posts above I explained why the haloform reaction on acetylacetone yields acetate and chloroform.
For the same reason ethyl acetoacetate can't yield the malonate, but acetate, carbonate (AcOH and CO2 after acidification), ethanol and CHCl3.
Once again, the haloform reaction is based on base catalysed enolisation, meaning that the most acidic hydrogens will be substituted with the halogen.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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PHILOU Zrealone
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Nicodem and Jamjar,
CH3-CO-CH2-CO-CH3 and CH3-CO-CH2-CO-O-CH2-CH3 will react, as mentionned Nicodem, in basic media and halogen:
1°) First on the two H of the CH2 between the two C=O
2°) Once they were used, under further treatment with exces halogen it will jump on the H of external CH3.
This would mean that in the end products, one will get:
For pentandione: HCCl3, and HO2C-CCl2-CO2H (dichloromalonic acid) (maybe giving HO2C-CHCl2 + H2CO3 or doubtfully CH2Cl2 + 2H2CO3)
For ethylacetylacetate: HCCl3, H2CO3, CH3-CH2-OH and CHCl2-CO2H (or maybe further CH2Cl2+ H2CO3?).
I'm not sure CCl2 will be able to split off like CCl3 partly because dichloacetic (dichloroethanoic) acid is stable acid and I never have heard or
read about such splitting.
I'm not sure about the stability of 2.2-dichloromalonic acid but it is mentionned in a few (7 or so) internet references aside with dichlormethane
[Edited on 6-2-2008 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
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Nicodem
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Unfortunately it is not that easy. Me-CO-CCl<sub>2</sub>-CO-Me in the presence of hydroxide is just as easily cleaved to acetate and
Me-CO-CHCl<sub>2</sub> as CCl<sub>3</sub>-CO-R type of ketones are in the haloform reaction of methyl alkyl ketones. So, you
can not perchlorinate acetylacetone and similar beta-dicarbonyl compounds under such conditions - they cleave faster.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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