Nitromethane Synthesis - Archive Thread

[Anthony]

Mammut
A new voice
Posts: 39
From: Essen,NRW,Germany
Registered: JAN 2001
posted February 13, 2001 08:58 AM
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hi,
do i get nitromethane if i mix
CH3OH with H2SO4/HNO3?
Can someone tell me the reaction
CH3OH + H2SO4/HNO3 ---> ???? + ????

thanks

[This message has been edited by ALENGOSVIG1 (edited February 13, 2001).]


atropine
Frequent Poster
Posts: 129
From: wales
Registered: OCT 2000
posted February 13, 2001 02:07 PM
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i would edit that post b4 any one sees it. you will be flamed.


wantsomfet
Frequent Poster
Posts: 233
From: EU
Registered: JAN 2001
posted February 13, 2001 03:32 PM
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The reaction for nitromethane needs several hundred degree C, if i remeber correct, and a platinum catalyst. Nothing for the hobbychemist.
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Cricket
Frequent Poster
Posts: 160
From: USA
Registered: OCT 2000
posted February 13, 2001 03:41 PM
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In KIPE2 (or was is it 1?) it tells the industrial procedure for making Nitromethane. It is very expensive to get the equiptment to make it. When I saw the diagram I just said "Fuck this.". I dont think their is an easy to make it. It is just too usefull for it to be easy to make.


MacCleod
Frequent Poster
Posts: 215
From:
Registered: DEC 2000
posted February 13, 2001 10:28 PM
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I beleive I read recently that only 2 chemical plants currently make nitromethane,that's one of the reasons it's so expensive.There was a supplier in South Carolina called F H S Supply,Inc. that sold NM racing fuel (for model cars,planes,etc.) with up to 65% NM in it.At that time the price was $30.48 per (single) gallon,or $21.34 per gal. when buying a case or more (4 gallons per case).This info is a few years old,but if you call them they'll send you a new price sheet;thier toll-free # was:
1-800-742-8484.
The toll # was:
1-803-222-7488.


megalomania
Administrator
Posts: 651
From: USA
Registered: SEP 2000
posted February 14, 2001 05:40 PM
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The industrial rxn uses methane gas at about 450 °C and several ATM's of pressure. Nitric acid (100%) is sprayed in through atomizer nozzels. I have thought about trying this by heating up an air pressure tank, but unless you have a good way to drain off the product, which I do not. yield will be crappy and time consuming.
Of course I do have a method of synthesizing nitromethane using laboratory equip/chems at my website if your interested.

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DarkAngel
Frequent Poster
Posts: 591
From: ?
Registered: SEP 2000
posted February 15, 2001 01:01 PM
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Finally i found a source in Holland that sells 99,6%Nitro Methane for 18 USD
I convert it with this site: <a href="http://www.xe.net/ucc/full.shtml" target="_blank">http://www.xe.net/ucc/full.shtml</a>
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Go to Section1 <a href="http://www.section1.f2s.com" target="_blank">http://www.section1.f2s.com</a> Alot off Bombs/Explosives and Homemade Weapons!!,,,Plus a &lt;&lt;Forum&gt;&gt;!!!


atropine
Frequent Poster
Posts: 129
From: wales
Registered: OCT 2000
posted February 15, 2001 01:36 PM
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Well, sorrey bout that, it would appear that you didn't. In the Uk nitromethane is commanly available in most model shops. And if they don't have it they will usualy get it for you at £14 a litre.

[xyz]

Shouldn't this be in chemistry related?

Does anyone know a supplier of nitromethane in Australia?

[0EZ0]

Nitromethane can be had for those who keep their eyes and ears open, as with almost all chems. A local RC model aircraft/car/etc. club would be a good place to start asking around. All you have to show is that you are a keen model aircraft/etc. enthusiast and you are looking to formulate some of your own fuel. Which could be quite true, as in my case <img border="0" title="" alt="[Wink]" src="wink.gif" /> . A bit of small talk, and there you have it :) .

<small>[ March 07, 2003, 06:18 AM: Message edited by: 0EZ0 ]</small>

[Mr Cool]

I think an OTC nitromethane synthesis will be in my plans for the coming weeks, it all seems easy enough. Vinegar, pool hypochlorite, a strong acid (HCl masonry cleaner, for example), nitrite from nitrate. It should be a nice experiment to try.
Has anyone here tried it before, and if so, do you have any tips which might help? At the moment I think I'll concentrate the vinegar using distillation from CaSO₄, Ca(NO₃)₂ etc a few times since I'm worried about side-reactions if using, for example, sodium ethanoate and sulphuric acid.

<small>[ March 08, 2003, 04:27 PM: Message edited by: Mr Cool ]</small>

[VX]

I have tried concentrating vinegar, and also making ethanoic acid from meths (denatured alcohol). I would suggest making it from alcohol any day; it's so much easier! All it takes is to reflux ethanol with a strong oxidiser, (e.g. potassium permanganate) for about an hour, and there you are, pure(ish) ethanoic acid!

[Polverone]

I don't think you should have any real worries about side-reactions between sodium acetate and H2SO4. But if you don't want to use H2SO4, you could use H3PO4 instead, as it is a weaker acid and dehydrating agent. However, since it is weaker, I would think you would surely want to use anhydrous sodium acetate. And it is somewhat tricky to completely dry sodium acetate without scorching it.

For the chlorination are you using phosphorus, sulfur, iodine, or a mixture as your chlorination aid?

[knowledgehungry]

I read megas synth and was wondering if there was a way to make chloroacetic acid(besides using red phosphorous) or an otc source for it.
Thanks.

[megalomania]

Chloroacetic acid is not the kind of thing you would find in the stores. I know of no product that uses it. It is pretty much limited to use in some organic synthesis setups and industrial operations.

It took me a few years to find the synth I have on my website. Since then I have seen no other method of producing it but the one I found. I think even the industrial method chloronates acetic acid like this IIRC. Modern processes use artifical sun lamps to get the reaction along, but those are specialized, and expensive, bits of equipment.

I am moving this thread to Chemistry Related.

<small>[ March 09, 2003, 01:24 AM: Message edited by: megalomania ]</small>

[Mr Cool]

Good, I'm glad you think I can use sodium acetate and sulphuric acid, Polverone. That should hopefully speed it up a lot. And if it does fuck up, then I'll try distilling from a dehydrating agent or fractional distillation.
Although, actually I think I might make it from ethanol instead. Originally I was going to try this synthesis using the most basic chemicals, but this wouldn't make it easier for everyone to make since it still needs some good glasswear. Ah, damn, but I don't have any permanganates or dichromates ATM. So I'll start experimenting with vinegar, and move on to making it from ethanol when I get more of a suitable oxidiser. I may have to order more calcium hypochlorite too, the stuff I have is quite old.

For the chlorination I'll use sulphur with iodine. I have a 750W filament lamp that I hope will give enough UV, if not this could take a long time!

[Al Koholic]

Mega, there is another reaction that does not utilize PCl3 (which is good because I really don't like the thought of conducting a reaction between P and Cl in my room). Rather it utilizes S2Cl2, SOCl2, or SCl2, and I think you can use things like S4Cl4 and whatnot. The one I am going to do uses S2Cl2 which can be easily prepared by bubbling a stream of Cl2 gas into molten sulfur at 295C. I have synths for all these if you want them. BTW, did you get the email I sent you a while back?

[megalomania]

Do you happen to have a ref for that procedure Al Koholic
? I have a synth for S₂Cl₂, but I don't know about the others off the top of my head. I turn down no offers of syntheses :) I most likely did not or do not have your email as mine has been quite buggy this past few months. Go ahead and send it again to webmaster@roguesci.org until I get a real address.

[Anthony]

If UV ye need, would a UV lamp not be more effective?

[megalomania]

I do believe the reaction requires visible light photons, not UV light to do the job.

[Tuatara]

Your bog standard, OTC quartz halide lamp will give you plenty of both!

[Mr Cool]

Ah, but both of those options are fatally flawed - I have neither a UV lamp nor a quartz halogen one :) .
I wonder... would generating Cl₂ in situ be better (would it still work as I am about to outline?)? It would be easier for me. It would mean I could have some MnO₂ in with the acetic acid and just drop in conc HCl through the top of the reflux condenser. Otherwise I'd need to use more glasswear and also make something to bubble Cl₂ in from one reaction flask into the other down the condenser. I have a feeling that making it in situ would be more efficient, even if slower, but I'm not sure why really... purifying the resulting chloroacetic acid would be just the same, it requires distillation anyway.
I'll try to find out more about making CAA.

Or maybe... oxidise ethylene glycol to 2-hydroxyethanoic acid, and reflux this with I₂ with FeI₂, AlI₃ etc as a catalyst? Maybe. Like I said, I'll try to find out more, including any other methods out there.

Edit: Or refluxing 2-hydroxyethanoic acid with H₂SO₄ and NaCl? I'm sure there are loads of problems with these last two methods, I'm just brainstorming and haven't thought them through yet.

<small>[ March 11, 2003, 04:05 PM: Message edited by: Mr Cool ]</small>

[Alchemist]

Hello all,

if you check out Rhodium's sight ,http://www.rhodium.ws/chemistry/chloroacetic.html, it says you can use Sulfur instead of Phosphorus but the yeilds are lower!

Later!!!

Also found that Wohler's organic chemisty says that Iodine can be used as a catalyst. Sorry no yeilds stated.

P.S., Al Koholic please do post your synth's for all of use. Thanks!

<small>[ March 11, 2003, 10:35 PM: Message edited by: Alchemist ]</small>

[megalomania]

Grrr! Didn't read MY website did we? I gave the procedure I wrote on CAA to Rhodium to use on his website :) Mine originates from Praxis Des Organischem Chemikers (Practical Methods of Organic Chemistry), which itself comes from some Chemishe Beristsche article of 120 years ago.

I would be wary of adding too many additional chemical to the reaction mix as possible side reactions can ruin everything. Besides I think you need to completly saturate the acetic acid with chlorine to get this to work.

Also I feel I should mention that the best light of all is sunlight, better yet in the summertime. Better get some mirrors this time of year. Without the proper amount of light the reaction will take longer, days longer, and all the while you need to be forcing vast amounts of chlorine into the flask.

[Einsteinium]

Troubles with Nitromethane? There's a lot of synth to achieve this in a clandestine lab setting...

Chlorination of acetone may be achieve with Cl₂ in a refluxing acidic media but this is tricky as polychlorination may well occur (chloroacetone is more reactive towards chlorination than acetone itself). I did it once and got a 32% yield, which isn't a bad yield since the reaction's nature. Chloroacetone reacts with nitrites and yield *both* nitrite and nitro coumpound (fortunatly the nitrite rearanges readily into the nitro at his bp). Nitroacetone is finally cleaved with NaOH to yield nitromethane and sodium acetate. I don't really like the first part of this synth so...

You can oxidize methylamine with 3 molar equivalent of any peracids to yield the acid, water and nitromethane :

CH₃NH₂ + 3RCO₃H -&gt; CH₃NO₂ + 3RCO₂H + H₂O

This reactions gives ~60% yield based on the methylamine used.

Nitromethane may also be prepared from :

Methyl Iodine and Sodium/Potassium Nitrite (high yielding)

Methanol + H₂SO₄ (or conc. HCl) and Sodium/Potassium Nitrite (~60% yield)

I think all above synths and a couple other can be found at <a href="http://rhodium.ws" target="_blank">rhodium</a>

I believe industrialists used to reacts methanol with nitric acid and then rearanges the methyl nitrate to nitromethane in the 'ol times but I guess we'll leave this method to the industrialist bastards :)

And please, don't use your 6 foot tall bong to relax while preparing this stuff... :D

[knowledgehungry]

Hmmm... The reaction using H2SO4 methanol and KNO2 would be the easiest i think, I dont have any KNO2 right now but i'm sure to get some sooner or later. I shall try and post back with results.

[Einsteinium]

I actually I never tried it out (I get nitromethane by distillation of some high-performance racing fuel @ my local hobby shop). For higher nitroalkanes I use the indirect alkyl halide/metal nitrite way. Some advices :

Never allow your vessel to reach reflux (MeOH/conc H₂SO₄ has significantly higher bp than MeOH alone) because you will be driving a side reactions that produces dimethylether! (gas!).. I would rather keep the temp @ at conservative room temp for a first attempt.. Might take a lot of time for the reaction to proceed but I would rather die of boringness than be knocked off by (CH₃)₂O :D

Also, I haven't played much with HONO (which is produced as H₂SO₄ reacts with NaNO₂) but I know it dismutates into HNO₃ with water at high pH and high temp. Another good reason to keep a low temp (you don't want nitric acid there in any noticeable concentration).

Adding Zinc Sulfate to the reaction will greatly helps the reaction has it complex the alcohol function into a better leaving group than water (you remove water with the simple synth).

If you can get your hand on NaI/KI (I heard it could be "easily derived from salt licks" but I don't have a clue about what are salt licks) I would rather produce CH₃I in situ :

CH₃OH + NaI + H₂SO₄ + NaNO₂ -&gt; CH₃NO₂ + NaHSO₄ + H₂O + NaI

1 - H₂SO₄ reacts with both NaI and NaNO₂ producing HI and HONO
2 - CH₃OH reacts with HI producing CH₃I and water
3 - CH₃I reacts with ONO^- (dissolved HONO) to produce nitromethane and NaI

As you might has understood, NaI acts as a catalyst here, you only need to add a small amount to get this reaction working properly.

Well, good luck with any synth you might choose but it is my opinion that you should consider fuel distillation instead. It's easier, quicker and cheaper!

<small>[ April 02, 2003, 09:57 PM: Message edited by: Einsteinium ]</small>

[Energy84]

The only 'salt licks' I've ever heard of are a sort of animal mineral block. The ones that we get are big 30 pound blue blocks. And yes they are salty... <img border="0" title="" alt="[Wink]" src="wink.gif" /> They can be purchased at almost any agriculture store. Just ask for salt blocks. You can get it in granulated form (for mixing into feed) and the block form. I'm not sure what the exact difference is but you can get them in blue or brown. I'd guess that the blue ones have more salt in them though because they are alot harder. (Dropping them on a concrete floor will chip them.)

[Marvin]

Some very nice ideas there. The chloroacetone idea I likw a lot, but the yeild is a bit poor, based on chlorine? Were you chlorinating the liquid (why was this acidic?) or the vapour above it under reflux, I understood yeilds were normally better this way.

The synthesis from methanol bothers me. A lot. Aside from anything else it looks too easy, this always bothers me. With dilute acid Id expect methyl nitrite gas to be the majority product with virtually no nitro product formed, the nitrite is explosive by itself even if you dont get an explosive mixture forming with dimethyl ether and air. HCl I cant see as working at all, and Id be worried that this would liberate large amounts of methyl nitrite and hydrogen chloride gasses when heated, with maybe some NOCl and NOx thrown in for good measure. If this was done stepwise through formation of methyl sulphate, I could see this working and giving overall the same result, but methyl sulphate is a tad on the toxic side for my liking. Sodium methyl sulphate looks rather safer if this method will work.

The catalyctic method with iodide looks more like a work in progress than a finished method, for example whats to stop the liberated nitrous acid from oxidising the liberated HI like youd expect it to, and this grinding the reaction to a halt?

[Einsteinium]

It was acidic because I wanted the reaction to proceed through the ionic mechanism (ketone -&gt; enol -&gt; chloroketone) directly bubbling the liquid instead of the free radical mechanism (ketone -&gt; ketone free radical -&gt; chloroketone) in the vapour phase. The reason why I don't do it anymore is because the first time I tried it, it went out of control and that was quite freaky to see acetone/chloroacetones splashing out of my damn ice-cold 30-cm condenser.

Methyl nitrite decomposes before it's boiling point, you won't ever get it as a gas at room temp. With dry ice you can get a decent yield of nitrite, but I don't think the methanol method is appropriate as it proceeds so slow at theses temps...

I have never heard of nitrous acid reacting with HI at usual temperatures, and truly don't think it does. Do you have reference about this?

[Mr Cool]

Well, I can say that 50% H₂SO₄ in water with an equal volume of 90% ethanol added and a spatula measure of KI will turn brown and deposit iodine crystals when NaNO₂ is added at room temperature. Also produced was a significant amount of acetaldehyde, and there was a slightly chloroform-like smell present. There was vigorous bubbling each time the NaNO₂ was added.
I didn't use any zinc sulphate.

But this does not mean it can't be done, more likely it means I should've found a procedure to follow first...

The haloketone route seems a good one, and today/tomorrow I will try making chloroethane and then reacting with NaNO₂ to yield nitroethane after fractional distilation to remove the ester.
I'll have to find my chem notes to get a synth for chloroethane, IIRC it's roughly the stoichiometric ratios of 50% H₂SO₄ with NaCl, with a ZnCl₂, AlCl₃, FeCl₃ etc catalyst?

[Einsteinium]

You can do it trough chloroethane but since chloroethane is a gas @ room temp and chlorine a somewhat cheap leaving group, I do it through bromoethane, which is a liquid @ room temp. Yields are usually high (~85%) with bromoethane and you usually don't need Lewis acids (Zn, Fe etc...) catalyst to get the reaction done. KBr can be found a photographic supply shop for ~10$ US/500g, reacted in situ with sulfuric acid to give HBr which then reacts with Ethanol to generates ethyl bromide. Ethyl bromide gives ~80% yield nitroethane with sodium nitrite, I've done it several times, the procedure can be found at rhodium. Sorry for the HI crap, didn't know it could be oxidized to iodine by nitrites (iodine reacts with ethanol to form acetaldehyde...)

[Mr Cool]

I haven't found a good source for KBr yet, but will keep looking...
Thanks for the advice.

[Marvin]

Dont be sorry, just put more difference between the ideas, particually untested ones, and information from reliable sources, like books.

Methyl and ethyl nitrite are stable as gasses, I think you must be taking a generalisation out of context here, becuase none of my information suggests they arnt stable. PAS Smith simply states they are gasses adding only that the alkyl nitrites decompose slowly at room temperature but can be kept almost indefinatly in a fridge. An encyclopedia states that ethyl nitrite solutions can be distilled at atmospheric pressure, as in the production of sweet spirits of nitre and that if heated too much the gas can explode, but that ethyl nitrite decomposes only slowly as a gas at room temp (no info on methyl nitrite). Sidgewick points out that in the victor meyer synthesis, the nitro and the nitrous esters of methyl, ethyl, etc have such different boiling points that separation is fairly trivial, and that the nitrous ester gasses decompose rapidly at 200C (he also talks about things like hydrogenation at lower temps). Theres no information in Sidgewick about isomerisation to nitro compounds, only the production of nitrous gasses and aldehyde. If this information comes from a patent, please remeber that these are very heavily biased and unrelaible sources of information on their own.

While I'm spreading misery mindlessly, I'll add a personal theory I have for why the catalyctic iodide method wouldnt work even if nitrous acid and HI didnt react. The theory is that formation of the nitroparrafin occurs becuase the poor solubility of silver or alkali halide in the reaction mixture. More obviosly becuase of the very low solubility of silver halides and the higher yeilds this method generally produces. In the catalyctic method, you are expecting the KI to be soluable for the conversion to iodide, and insoluable for the conversion to nitroparrafin. Sidgewick does talk about change in yeilds of silver over alkali and also the relative change in yeilds for primary to tertiary, and for different chains. I think the synths in which alkly nitrites might form need to be reevaluated in terms of safety at least, if not in terms of validity.

I dont like the acetone+acid method. I have the sneaking feeling that the reason it went out of control, was that the chlorine was reacting mainly with aldol products, which I see no way of preventing under these conditions. I dont have any way of checking the free radical method by lituriture, but chlorination in bright light of the vapour above reflux seems to me like the way to do it. The higher boiling point of the chloro products should mean that much less of these are present in the vapour than in the liquid, with less di chloro compounds being formed, and an acid absorber of some sort (calcium carbonate?) in solution to prevent acid build up and aldol equilibriums screwing things up.

Lastly, if you still need convincing about methyl nitrite existing in gas phase at room temp, check out organic synthesis. While often not the best way, and occationally downright dangerous, the synths do always work and methyl nitrite is generated at or neer room temperture and bubbles into a reaction from the generating flask in the "ISONITROSOPROPIOPHENONE"
synthesis.

Ok, that wasnt the last, this is, PAS Smith lists a ref that states alkyl chlorides dont work at all in the victor meyer synthesis. Id call a cheap leaving group one they went really easily (!), but I know exactly what you meant:- chlorides are cheap and they are crappy leaving groups. The specific ref for this is Kornblum, B Taub and H.E, Ungnade, J Am Chem soc. 76, 3209 (1954)

[Einsteinium]

Well, actually if I don't give any litterature to check I assume that you will before trying anything I may post unless you too, assume it may well work. The theory behing theses reactions is called bimolecular substitution (S_N2) and dosen't stand at all over solubility in the solvent you are using. Next, acetone dosen't undergo self-aldolisation unless a very strong base is used, it went out of control because way too much chlorine was passed in the acetone creating a temperature increase I couldn't prevent quickly enough. Free-radicals formed with halogens dosen't undergo aldols condensation at all. Methyl and Ethyl nitrite aren't stable, they decompose as you say at room temp. Slowly maybe, but quite quickly in such heated acidic media. Silver nitrite is known to reacts faster in this synth because silver acts is a lewis acid (just as Zn or Fe, mentionned by Mr. Cool) which complex the alcohol creating a better leaving group and because silver nitrite isn't an ambivalent nucleophile, the reaction works better with tertiary halides because they can form stable carbocations and react through monomolecular substituion instead (S_N1). Yes organic synth use gaseous methyl nitrite @ near room temp, but they do use it immediatly and they dosen't produce it from acidic media. I said that if you want the nitro coumpound with the methanol synth the only way would be a very low temp where the nitrite is stable even in acidic condition, but this reaction is worthless. Do a simple search about bimolecular substitution on any decent site and you will find out how this synth work. Any decent organic chemistry book has a complete chapter about it too, might be informative.

[Edit : Here's a good theoretical reference : <a href="http://www.ch.ic.ac.uk/widdowson/teach_files/nitrogen/dw1.html" target="_blank">http://www.ch.ic.ac.uk/widdowson/teach_files/nitrogen/dw1.html</a>

<small>[ April 05, 2003, 07:38 PM: Message edited by: Einsteinium ]</small>

[Marvin]

"Well, actually if I don't give any litterature to check I assume that you will before trying anything I may post "
If you truly believe this, I think you are the only one. Giving references, or suggestions of books that cover the specific subject is a good idea if you want people to go out of their way to double check suggestions.

Ive read what I have on the subject, come to some conclusions, and feel happy making the following suggestions......

"The theory behing theses reactions is called bimolecular substitution (SN2) and dosen't stand at all over solubility in the solvent you are using"
For primary haloalkanes, it is indeed SN2 as shown by kinetics studies, but choice of solvents and the solubility of the reagents is critically important, for example, DMF over DMSO generally requires nitrite scavangers to prevent nitrosation reactions that occur because of the increase in reaction time due to lower solubility of the sodium nitrite. More importantly, the fact the reaction is clearly SN2 from the kinetics overlooks an important feature, the reactants get used up and the products taken together form almost quantativly. Your making this an unvoiced assumption, and then wondering where my argument applies.

If we look at the production of haloalkanes,

ROH + HBr &lt;=&gt; RBr + H2O

Although SN1 or 2 tells you what can happen kinetically, and thus some information about the products, it doesnt tell you if the reaction will go forwards or backwards. In the case of a simple mixture, this reaction goes mostly where its driven, a secondary or tertiary haloakane mixed with water will rapidly hydrolyse, primary haloalkanes being SN2 would do also, but are kinetically limited by the availability of OH- so although it wont be destroyed under these conditions, it wont be formed either. To make haloalkanes the reaction conditions are changed and you have 2 powerful factors favouring formation of product rather than reactant, you add strong acids/dessicating agents like sulphuric (slightly oxidising, so a problem with HI) or phosphoric acid, and you remove the low bp haloalkane from the reaction mixture by distillation.

I'm arguing that formation of NaX or AgX in particular is a strong incentive for the reaction to proceed to completion. I also think that the use of haloalkanes in this reaction isnt 'catalyctic' as such, just a way of seperating the conditions required for facile and neer complete nucleophilic substitution of the alcohol, from the reagents these conditions are incompatable with. In order words, if you can stabilise this, and void competeing reactions kinetically or thermodyanically (if possible, the nitroalkane is the better themodynamic product over the ester), I think direct nucleophilic substitution would be facile on its own, and would not by improved by iodide ions, which you are expecting to jump in and out under the same conditions.

"acetone dosen't undergo self-aldolisation unless a very strong base is used"
This simply isnt true. It doesnt go to completetion with dilute acid because the products arnt favoured, unlike strong base, which tends to produce insoluable polymers. If you make acetone moderatly acid you get a solution of mostly acetone, with a few percent of aldol products, diacetone alcohol, metsylene oxide etc. I'm bothered that these would react with chlorine far more readily than acetone itself, reduce the yeild, and make the chlorination less easy to control.

If you go furthur with acetone, by saturating it with HCl gas the reaction goes much furthur, as dehydration sets in. Left for a day and then neutralised, treatment with water produces an oil which is mostly metsyl oxide and phorone, which can be seperated by distillation.

"Free-radicals formed with halogens dosen't undergo aldols condensation at all"
Free radicals do a lot of very weird unpredictable stuff. My suggestion though was to prevent buildup of large amounts of HCl in the mixture that would cause high amounts of aldol products, and dehydration products of these to be produced all of which would be much easier targets for chlorination. The synthesis book by MB Smith deals mainly with bromination of ketones in this area, but gives an interesting twist. KClO3 is added to the ketone mixture and any HBr formed is oxidised right back to Br2. This prevents large amounts of HBr from building up in the mixture, and also potentially halves the amount of Br2 required for the reaction.

"Methyl and Ethyl nitrite aren't stable, they decompose as you say at room temp"
They are stable enough to provide a very serious hazard to people attempting these reactions. They are also stable enough as products of the primary reactions to put formation of nitroalkanes from the alcohol in some considerable doubt. This particulaly as they dont decompose to the nitro compound, but to the aldehyde and NO. Acid media isnt likley to be relavent, as with any setup anyone might be able to try at home the nitrite esters will go straight out of solution, being gasses and leave.

"Silver nitrite is known to reacts faster in this synth because silver acts is a lewis acid (just as Zn or Fe, mentionned by Mr. Cool) which complex the alcohol creating a better leaving group and because silver nitrite isn't an ambivalent nucleophile"
I dont like the term ambident nucleophile, but this is certainly the main reason for the increase in yeild of nitro compound over nitrous ester. In these reactions the shorter reaction time the more product, so I also consider the formation of AgX to be a factor kinetially as well as thermodyanically, and the ability to produce more concentrated solutions of the nitrite nucleophile, much more of a issue with sodium nitrite reactions. I dont buy the lewis acid complex argument in this situation for reasons I mention later. Theres no alcohol involved, and the leaving group is the halide, so I dont see what you are getting at here.

"the reaction works better with tertiary halides because they can form stable carbocations and react through monomolecular substituion instead (SN1)"
This simply isnt true, yeilds are worse with victor meyer with secondary and tertiary halides than with primary. With primary halides silver gives typically 80%, sodium 60%. With secondary halides silver gives less than 15% , sodium gives much better yeilds, up to 60% but generally less than with primary, more problems with competeing reactions, nitrosation products, the expected nitrous esters 'low temperature' nitrate ester formation and large amounts of dehydrohalogenation which form olefins and then go on to react furthur, usually with nitrogen oxides. Getting these fairly high yeilds with secondary halides is usually a matter of choosing a solvent sodium nitrite is very soluable in, and adding nitrous ester scavingers such as phloroglucinol to hinder nitrosation by the resulting alkyl nitrites. Tertiary halides with silver typically give 5% yeilds at best and the nitro product can usually not be isolated from the reaction mixture, they instead form high yeilds of nitrous esters, olefin addition products etc. I dont have enough examples to be able to draw proper conclusions from sodium nitrite with tertiary halides, but the general trend is that the only high yeild products are olefins, for example t-butyl bromide and chloride fail to give nitro compounds, but form isobutylene instead. The only suggested practical route to tertiary nitro compounds here is the oxidation of amines, with very satifactory yeilds, 60 to 90% by peroxyacetic acid, or permangante (permanganate doesnt give great yeilds with primary amines).

I'm not totally sure you intended to state tertiary halides give better yeilds, but maybe you meant secondary halides give better yeilds with sodium over silver nitrite, something quite often quoted. This is one of the principal reasons I dont put any credit to the idea that silver acting as a lewis acid stabilises the complex, and just in case you want to say 'steric hindrence' lithium, sodium and potassium nitrites all give similar yeilds.

"I said that if you want the nitro coumpound with the methanol synth the only way would be a very low temp "
Actually you said that dry ice would be the only way to get a good yeild of the nitrite, which was consistant with your idea that methyl/ethyl nitrites did not exist in the gas phase. If side reactions can be stopped, particulaly oxidation, conversion of nitrite to nitrate in the strong acid etc in conditions where nucleophilic substitution of the alcohol can occur then formation of some nitro compound is possible, but in all normal home conditions it wont happen. Formation of the alkyl nitrite will occur which does not require nucleophillic substitution, or the breaking of the alcohol C-O bond.

"Do a simple search about bimolecular substitution on any decent site and you will find out how this synth work"
I will do my best not to be insulted that youve just suggested I look up pre degree information. :p

"Any decent organic chemistry book has a complete chapter about it too, might be informative."
University level organic chemistry textbooks dont provide the detail needed to design a synthesis in the complete absense of good chemical reasoning that this would form as a majority product, or in the absense of anything similar working practically. Mechanism only gets you a 'maybe this could form', its usually existing high yeild syntheses for similar products that suggest a high yeild synthesis is possible.

I'm currently limited to information I have at home, and the really detailed stuff ends around the mid 60's. University textbooks dont go into neerly enough detail about this stuff dispite being technically 'up to date'. If anyone has some more recent detailed information, Id like to see it particualaly if it disagrees with aspects of what Ive said. What is your reference for the 60% yeild from methanol/H2SO4/nitrite, and what are the exact conditions used? Youve suggested dry ice, we know it cant work at room temp, but if all the species can be stabilised removing kinetic limitations the nitro compound could form as the thermodynamic product, given long enough.

<small>[ April 12, 2003, 04:12 PM: Message edited by: Marvin ]</small>

[Einsteinium]

"If you truly believe this, I think you are the only one." I didn't gave any ratio of reactants, temperature and/or time in any suggestion I made! Are people crazy enought to ignorantly mix chemicals in random amount just to see how it might goes? This is damn crazy... Also, I told most of theses synths were on rhodium <a href="http://www.rhodium.ws" target="_blank">www.rhodium.ws</a>, I cannot find the page "nitroalkanes directly from alcohols", which WAS there (I wish I had backuped(sp?) the site) and the reference given was Fieser but I cannot remember from which book of Fieser. Maybe they removed it as they knew it didn't work well...

"a secondary or tertiary haloakane mixed with water will rapidly hydrolyse" I wouldn't say "rapidly" here, as I did clean several alkyl halides (more than 50 different, even tertiary halides) with water and lost nothing but a minime fraction of product. I know what you meant though, refluxing (or heating over 50C) an alkyl halide with plain water will hydrolyse it quite quickly. The solvent was simply an excess of alcohol so it's pointless to speak of DMF or DMSO as solvents.

"Although SN1 or 2 tells you what can happen kinetically, and thus some information about the products, it doesnt tell you if the reaction will go forwards or backwards." That's true, and yes it's why one must add a lot of acid to drive this reaction in favor of the alkyl halide. Removing the halide will definitivly drive the reaction this way too.

"I'm arguing that formation of NaX or AgX in particular is a strong incentive for the reaction to proceed to completion." We are in solution here, thus we speaks of ions. In no way NaX or AgX are produced in this reaction Na⁺ or Ag⁺ comes from the nitrire, X^- from the acid. Theses ions should stays dissolved as the reaction runs.

"which you are expecting to jump in and out under the same conditions." As I stated, I haven't played much with HONO (did a diazonium salt once, that's it). The use of Iodide as a catalyst (jumping in and out) is a common artifice used to catalyze many reactions such as : EtCl + AcONa -&gt; AcOEt + NaCl. This reactions sucks as is, but adding some NaI catalyze it (look for the Finkelstein reaction) since the iodide ion jumps in and out (I^- is a better nucleophile AND better leaving group than chloride, this is why it jumps in and out).

"My suggestion though was to prevent buildup of large amounts of HCl in the mixture that would cause high amounts of aldol products, and dehydration products of these to be produced all of which would be much easier targets for chlorination" I wouldn't say high amounts but overall you are right here too. However, what I did said is that the reaction didn't went out of control because of this aspect, it went out because I chlorinated acetone way too strongly (the flux of Cl2 was way to high) which resulted in a temperature build-up and lost of the reaction control.

"This particulaly as they dont decompose to the nitro compound, but to the aldehyde and NO." I should have said rearrange, not decompose, a procedure to achieve this can be found in "Panchanan, Neogi and Tarinicharan Chowdhuri, [can't remeber the journal] p.701-707 (1916)" This procedure can also found at rhodium's.

"I dont buy the lewis acid complex argument in this situation for reasons I mention later. Theres no alcohol involved, and the leaving group is the halide, so I dont see what you are getting at here." There is alcool involved in the process of alcohols to nitroalkanes! The first leaving group was water (from protonated alcohol) there is where Ag⁺ plays a major role. Also, Ag⁺ does form complex with alkyl halides, also making them better leaving groups. Keep in mind this is dissolved, there's no AgX in the media unless it's a precipitate of AgX.

"I'm not totally sure you intended to state tertiary halides give better yeilds, but maybe you meant secondary halides give better yeilds with sodium over silver nitrite, something quite often quoted." Tertiary halides would give better yields, but certainly not in solvents we are speaking of here (5% is a good yield in theses solvents IMO). One would be left with tertiary alcools, and/or ethers, alkanes, alkenes...

"This is one of the principal reasons I dont put any credit to the idea that silver acting as a lewis acid stabilises the complex, and just in case you want to say 'steric hindrence' lithium, sodium and potassium nitrites all give similar yeilds." I never said the reaction would give a better yield since Ag⁺ complex the leaving group, I said it would proceed faster, this is VERY different. Actually the yield would be inferior with most sustrate because the AgX⁺ leaving group is so good that elimination take place in a greater extent, which lower the yield of nitroalkane. Does that help buy the Lewis complex theory, it does lower the yield and accelerate all reactions where this leaving group is "called upon", this include elminations, substitutions etc...

"Actually you said that dry ice would be the only way to get a good yeild of the nitrite, which was consistant with your idea that methyl/ethyl nitrites did not exist in the gas phase." I am still a partisan of this theory, as long as we are speaking of good yields (&gt;75%).

"What is your reference for the 60% yeild from methanol/H2SO4/nitrite, and what are the exact conditions used?" as I said, it was on rhodium (with HCl instead of H2SO4) and Fieser was quoted, I will do my best to dig out a similar procedure as I am certain I saw it once (as I did consider it seriously). If my memory serves me well, the conditions were room temp, 18-24hrs reaction time, excess of alcool (as solvent), conc HCl in twice the stochiometric amount and sodium nitrite in 1,25 stochiometric amount. I will try it if I can get my hand on some nitrite salts. BTW, I am not really fond of the procedure, as I prefer alkyl halides all the way.

"I will do my best not to be insulted that youve just suggested I look up pre degree information." I am deeply sorry for that as I do respect you and your ideas, please forgive me. While reading my posts I often find myself quite insulting, which isn't really my intention, thus I'll put more effort in Engligh language diplomacy (my prime language is french, so please forgive the pathetics grammar/spelling/syntax errors while we are here <img border="0" title="" alt="[Wink]" src="wink.gif" /> ).

<small>[ April 12, 2003, 05:22 PM: Message edited by: Einsteinium ]</small>

[Marvin]

"Are people crazy enought to ignorantly mix chemicals in random amount just to see how it might goes?"
Yes.

Most people are capable of working out rougly how much of each reagent is required for a hypothetical reaction, and most people will automatically think experimentation is the way to solve the missing information problem. Since the answers are usually in books they dont have access to, or know where to look for relavent material...

I speak a lot about DMF or DMSO because I have about 4 dozen tabulated yeilds of nitro compounds done in them. (Before anyone asks, this stuff is on the to do list). Its stated these are used becuase of the high solubility of both the haloalkane, and also of the metal nitrite used. The corrisponding alcohol is avoided becuase of the difficulty in removing it from the reaction mixture. If yeilds are also lower, this would be another unstated reason. If the speed of victor meyer is greater in alcohol than in DMSO, for example, with the same concentration of reactants, then Id buy that for a doller.

I'm aware of reactions like iodine catalysed hydrolysis, but I dont see this as jumping, more of a faster method to fall. Each stage in the catalysis produces a more stable state than the previos one. Thus iodide will completly replace chloride, and both will almost completely hydrolyse under the same conditions. The iodide is an intermediate state, and thus its the activation energy of the attacking reactions that mostly matter. (SN1)

I did wonder briefly about iodine catalysed chloride reactions for nitro compounds, but the increased reaction time over pute iodides would probably significatly affect the yeild fo the product, and couldnt be done with silver.

In the proposed iodine catalysed from alcohol reaction, since iodine is completely replaced in victor meyer reaction with nitrite, you have a higher energy state as intermediate in the form of the alkyl iodide, and expecting the reaction to jump over this additional hurdle, and be faster, While this doesnt totally rule out the net attacking complex of the iodide to the alcohol, being less of an energy barrier than the attacking complex of the nitrite it does cast considerable doubt.

Ive read the conversion of alkyl nitrite paper. It doesnt give specific yeilds, and it only suggests the resulting solution tests positive for nitroalkanes, but it seems likley the yeild is in the region of 5%. Presumably the main product of this reaction is the aldehyde and NO with a small amount of unreacted alkyl nitrite. If you think a good yeild is 75%+, then the term for this would have to be 'diabolical' given the nitro compound as the goal. Anyone setting up a flow reactor like this would be far better using methane bubbled through nitric acid, not just becuase of the explosive nature of the alkyl nitrites.

"We are in solution here, thus we speaks of ions."
The situation I'm refering to is the classical victor meyer, in an organic solvent. Ionisation is a rare thing, and even the website you referenced has the attacking species as the whole metal nitrite. In order to be a difference beteween them they have to attack as a total group, and it seems likley AgX would leave as a single group too. Either way, the very low availability of X atoms effectivly prevents the back reaction even if nothing else does, and this was my point.

Maybe Rhodium can jump in with the missing page and why it was removed.

[DF90]

I was thinking that it might be possible to react nitrogen dioxide with methanol to yeild nitric acid and a methyl radical... which would then react with a nitrogen dioxide molecule (which is a radical) to form the nitromethane? What i would imagine to happen is the nitrogen dioxide gives an electron to the oxygen atom in the hydroxyl group, which then bonds to the nitrogen dioxide yielding nitric acid, and breaks away from the carbon atom (homolytic fission), leaving behind a radical :P This reaction would be extremely useful as it cold possible be applied to synthesise other nitroalkanes and the nitric acid byproduct is very useful also :D Just not sure if it would work... maybe someone could try experimenting with this concept?