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Author: Subject: Carbon monoxide preparation?
zephram
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[*] posted on 31-1-2009 at 15:11
Carbon monoxide preparation?


Sugar reacts with sodium hydroxide to produce carbon monoxide. It seems like a slow reaction, though may be speeded by heatinig. Can anyone speculate on what's going on?

There are of course more effective ways of preparing this gas but in principle this seems to have the advantage of using readily available materials.
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Ozone
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[*] posted on 31-1-2009 at 20:44


Sucrose does not do much in alkali (at room temperature). Please use the search engine in the upper left hand of the page (under the flaming sigil).

Try looking up something like formic acid...

Cheers,

O3




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JohnWW
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[*] posted on 31-1-2009 at 21:01


What do you want to prepare CO for? The stuff is deadly poisonous to inhale, comparably to HCN, (CN)2, H2S, and H2Se. If you want to handle fairly large quantities of it, use a fumehood, and preferably wear breathing apparatus with bottled air. There are three possible chemical uses that I can think of for it - for the refining of Ni from crushed ores in the form of ultrabasic rocks, with which it readily forms the volatile tetracarbonyl Ni(CO)4; to produce carbonyls of other transition metals with partly empty d orbitals; and, being the anhydride of formic acid, to react with alcohols or phenols to make formate esters.

If you could do with formic acid instead in order to make formates, this can be obtained by the oxidative cleavage of many sugars, particularly glyceraldehyde, with HIO4 or Pb(CH3COO)4. The formic acid can then, if desired, be dehydrated to CO with H2SO4.
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[*] posted on 1-2-2009 at 18:55


Someone around here was preparing sodium gluconate or sucrate (cant remember which) with sodium hydroxide and glucose or sucrose. Never found much information on synthesis, but i would be interested if anyone had any.



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[*] posted on 1-2-2009 at 19:38


Sucrates are salts of gluconic or glucaric acids (that is, the hexose acids). In industry, the "sucrates" or "saccharates" are no such things (jargon). These are usually complexes (with sucrose, anyway), not salts of the original carbohydrates (e.g. tricalcium sucrate). This is easily and completely reversible (the reducing sugars are destroyed yielding the brown/black tar that colors most impure mixtures of this kind).

Synthesis is easy. Just add lime (or other alkali), a little heat, and wait. Sucrose increases the solubility of Ca(OH)2 by a factor of roughly 12, relative to water at the same temperature. This is due to the complexation. This mixture is frequently used, in place of lime, to effect the clarification of cane juice (saccharate liming).

So, non-reducing sugars (like sucrose) don't do much whilst reducing sugars (glucose, fructose, etc.) are easily destroyed. The free carbonyl sets up the tautomerization required for reverse aldol scission and subsequent condensation reactions to occur.

Cheers,

O3




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[*] posted on 2-2-2009 at 04:55


The good old chembook states as reaction for CO-preparation : H2SO4 + formic acid ;

The danger is, that CO has no smell ; you don't feel it coming, just fall asleep, and gone you are ... ; that's how accidentally people make it to the eternal hunting grounds ever again, by malfunctioning ovens etc.
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[*] posted on 2-2-2009 at 05:46


It indeed can very easily be made from formic acid. Drip concentrated sulphuric acid into 60% formic acid and while the liquid heats up (reaction of water and H2SO4), it also starts foaming, giving bubbles of CO. The reaction is quite fast and smooth. In this way I have made a few test tubes full of CO.

As stated by others, CO is VERY dangerous, much more so than Cl2 and many other toxic gases, because it has no warning properties, nothing at all. Even if the gas is present in deadly concentration, you won't notice, until you suddenly loose conscience and fall down. There is no smell, no fumes, no irritation, nothing. So, do this experiment in a very good fume hood, or work outside on a breezy day.




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Jor
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[*] posted on 2-2-2009 at 06:56


I do really think people overrate CO.
Although it is colorless and odourless, you have to inhale quite high concentration to die or collapse.
Typical STEL , maximum exposure for a short time, is 300ppm. Then you won't suffer effects! Now if your works outside, on a windy day, there is no way that concentration will be reached. You will have to release 300mL of pure CO per m3 to reach an exposure that is not even harmful at short periods!
I read somewhere that on the streets of mexico city, CO concentration is about 100ppm!
Now try that with other common poisonous inorganic gasses.

When you work outside with chlorine, do ever suffer from severe irritation? I did not, when I worked without a hood, and there was not much wind. This means concentrations were lower than 10ppm, wich is described as unbearable. And CO will dissappear even more quickly than Cl2, as it is much lighter.

So myself, I would not worry too much. If you generate small amounts of CO gas, outside, you are not likely to get injured or worse, unless you stick your nose right above the flask (where it is concentrated). But in that case, chlorine will kill you as well, having no time to respond.

Even though it is one of the number 1 chemical killers, it always kills people that are unaware of it's presence, and concentration may be very high, because houses are not ventilated, especially when it's cold. Now if you generate some in a controlled fashion, and you KNOW how much is released (so you can calculate potential concentration), I do not see any accidents happen. And headache/tiredness are symptoms, so you are not totally unaware you are inhaling too high concentrations, if you KNOW it is there.

I would work inside with small volumes of CO, without hood. We all stand in front of a barbeque as well, for an hour. Ever thought of CO concentration you are inhaling when you barbeque?

Ofcourse, my advice is still to be very careful, and treat it as potentially dangerous gas. But treating it like it is HCN is exaggerating.

A table:
Concentration Symptoms

-35 ppm (0.0035%) Headache and dizziness within six to eight hours of constant exposure
-100 ppm (0.01%) Slight headache in two to three hours
-200 ppm (0.02%) Slight headache within two to three hours
-400 ppm (0.04%) Frontal headache within one to two hours
-1,600 ppm (0.16%) Dizziness, nausea, and convulsions within 45 minutes. Insensible within two hours.
-3,200 ppm (0.32%) Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.
-6,400 ppm (0.64%) Headache and dizziness in one to two minutes. Death in less than 20 minutes.
-12,800 ppm (1.28%) Unconsciousness after 2-3 breaths. Death in less than three minutes.

So for example after breathing 200ppm for 2 or three hours gives you a slight headache. Breathing chlorine, NO2, HCN, H2S, etc would have killed you by then.
[Edited on 2-2-2009 by Jor]

[Edited on 2-2-2009 by Jor]
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[*] posted on 2-2-2009 at 07:43


Quote:

And CO will dissappear even more quickly than Cl2, as it is much lighter.

CO has nearly the same dansity as air ... so it mixes perfectly
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watson.fawkes
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[*] posted on 2-2-2009 at 10:22


Quote:
Originally posted by Jor
Even though it is one of the number 1 chemical killers, it always kills people that are unaware of it's presence, [...]
An excellent point, one that I'll reinforce by pointing out that CO detectors are inexpensive (< USD 20) and they can go right next to the fire detector in the lab.
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zephram
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[*] posted on 7-2-2009 at 14:04


My thanks to all for the contributions. All good stuff though unfortunately mostly fairly wide of my initial question. Yes, I had used the search engine before posting, both on this site and the web in general. I found no shortage of the very familiar stuff on toxicity and standard methods or preparation, but only brief mentions of my original enquiry which was about the preparation of carbon monoxide from sugar (sucrose) and sodiun/potassium hydroxide.

http://en.wikipedia.org/wiki/Carbon_monoxide was fairly typical and gave:

"Another laboratory method to generate carbon monoxide is reacting sucrose and sodium hydroxide in a closed system."

I'd be interested to hear if anyone has more practical details.
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[*] posted on 7-2-2009 at 14:13


That probably requires high temperatures and pressures, well beyond the ability of a home chemist.
If you need CO stick with the ideas mentioned in the thread ( formates + conc H2SO4)
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[*] posted on 7-2-2009 at 17:00


I haven't seen this method in any of the older literature, which describe using HCOOH or C2H2O4.2H2O with conc. H2SO4 for laboratory methods of preparation.
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zephram
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[*] posted on 7-2-2009 at 19:10


> That probably requires high temperatures
> and pressures, well beyond the ability of a
> home chemist.

Well maybe ... or maybe not. Heating a couple of grams of sugar with a simar amount of NaOH and water in a test tube produces gas that burns with a blue flame.

Also some Materials Safety Data Sheets for caustic cleaners warn of using it in tanks used that may contain traces of sugar solutions.
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[*] posted on 7-2-2009 at 19:31


The cheapest method for making CO would be to put charcoal in a tube furnace, heat to 1000°C and lead in CO2 at one end. At the other end you get a mix of CO (mostly) and CO2. Wash out the latter with aqueous NaOH and you have your CO.
The reaction of CO2 with C is endothermic, hence the tube furnace, and an equilibrium.




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Picric-A
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[*] posted on 8-2-2009 at 10:40


@ zephram - There are many gasses that burn with a blue flame,
Do a CO test on the gas produced, and find out for sure, I am currently away from my lab so its up to you.
Personally, however, i try to stay well clear of CO whenever possible,
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[*] posted on 8-2-2009 at 10:53


http://www.orosha.org/interps/1981/dairyequipconfinedspace.p...

Reaction of NaOH with sucrose to produce CO is likely a misinterpritation of this, mentioned in a wiki, and widely copied without review.
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[*] posted on 9-2-2009 at 00:04


Great link Eclectic!
how exactly did you produce a 'gas that burns with a blue flame' ,zephram ?
Is seems unlikely to work with normal sugar (sucrose), or did you use another sugar?
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[*] posted on 9-2-2009 at 11:12


A burning pale-blue flame is suggestive of CO (note its LEL: 12.5, UEL: 74.0 - that's almost like hydrogen!), but this is a pretty primal test, though still not entirely indicative. More qualitative, and still simple tests rely on its reducing power. It will blacken silica gel (or PdCl2-soaked paper). A blue-green color from silica gel which is soaked with a solution of I2O5 in conc. H2SO4. Light purple aq. KMnO4 solutions are said to go colorless. If there is CO, then it might be impure. CO2 might be one of those impurities, testing for CO2 is as simple as leading the gas through a clear Ca(OH)2 solution, where CaCO3 precipitates.

The reason why CO is often placed with compounds like HCN, etc. is because they are all blood poisons, note that does not mean as deadly as HCN, just going by toxicological action. In the case of CO, it will react with the hemoglobin to form carbon oxide hemoglobin (HbCO), this reaction has a far higher affinity than that competing one of O2. CO is an insidious poison, because of its odorless nature. It should not be underestimated, but also not overestimated.
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[*] posted on 9-2-2009 at 14:00


The cheap detectors seem all to only beep at a limit-value, but reading the conc. is not possible.
A good one, with 1% accuracy, I couldn't find below > 100 EUR ; such a one would be much more useful ...

From conc. CO one breath may be deadly, within short time ...
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[*] posted on 9-2-2009 at 14:07


Same for chlorine, bromine, etc.

The fact is that, at concentrations where CO would be lethal, it's detectability is not important anymore as any other toxic gas would knock you down at the same concentration as well, without you being able to respond. When CO is lethal, other gasses are as dangerous as well, as they kick you down in one breath.
In neither cases you have time to respond. At least you get headache symptoms with CO.
I'm not saying CO is something to play around with carelessly, but please look at the concentration table I posted, those concentrations are not easily reached. I would be FAR more afraid of Br2, NO2, H2S, HCN, to wich CO seems like a toy to me.

It surprises me that some gasses are overestimated by people and some are underestimated. I think many people overestimate things like CO, while H2S is greatly underestimated (although not anymore on this forum, because of Klute's scary story).

[Edited on 9-2-2009 by Jor]
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[*] posted on 10-2-2009 at 05:06


Wasn't there a fad in Japan not too long ago where people were mixing bath salts and some other OTC product in order to commit suicide by CO poisoning?

EDIT:Nevermind. It was hydrogen sulfide.

[Edited on 2/10/2009 by FrankRizzo]
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[*] posted on 10-2-2009 at 06:30


But CO is breathed in without notice - just like air. At the same time chlorine etc. will probably hurt the nose quite badly and give some warning that way ...

Probably it's not easy at all to breathe in the deadly chlorine-dosage ; long before one would get away from it, just by the smell ...

[Edited on 10-2-2009 by chief]
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Jor
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[*] posted on 10-2-2009 at 10:13


I agree that CO is breathed without notice but yo didn't get my point. We compare these gasses, so compare same concentrations...
Chlorine gas at say 100ppm is very dangerous, but you can indeed flee. But at the same conc. CO is not even dangerous... You can breath these levels for hours and get a slight headache.

Now at concentrations where CO is lethal, say 1000ppm+ (and that even takes a very long time, hours, before you die), chlorine doesn't warn anymore and kicks you down on the ground in one breath. So it doesn't give warnings anymore as well.

Therefore I can easily conclude Cl2 is more hazardous. To be honest, when you KNOW you generate CO, there is very little chance you die, when I look at the ppm data/health effects posted above. I would generate a liter of CO inside, no problem. Just try that with chlorine, and compare the effects.
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[*] posted on 27-3-2009 at 13:58
CO from Na Nitrate and Charcoal


Hello,

Some stuff here on making CO from a cartridge of Sodium Nitrate and Charcoal. May be suitable for lab. work.
Would Ammonium Nitrate do instead of the Na Nitrate?
Dann2

Attachment: CO.zip (401kB)
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