Sciencemadness Discussion Board

Question on making CH3NO2?

kclo4 - 13-5-2005 at 21:04

Would this work for making CH3NO2?

If methyl chloride (CH3Cl) was to be added to potassium nitrite (KNO2) would it react and make CH3NO2 and KCl or would there be a different reaction?

ChemPhile - 14-5-2005 at 00:16

I donnt think so. i think you ll get this product, methyl nitrite ester, whose molecular formula is CH3ONO, not CH3NO2.

Borek - 14-5-2005 at 00:32

There will be no reaction at all IIRC.

[Edited on 14-5-2005 by Borek]

Marvin - 14-5-2005 at 06:40

Well, I dont see anything obvious to say it can't work.

Methyl chloride being a gas would introduce some problems, the reaction is going to be really slow even at high concentrations. This means doing the experiment under pressure. You'll need a solvent that dissolves both the nitrite and the methyl chloride, the classic DMSO should potentially work. You'll want to switch to sodium nitrite for solubility reasons I think. You will also need something to destroy nitrites as they are formed, but in such a way as your container doesnt explode.

If the plan was just to bubble the gas through something and say 'tada nitromethane' you'll be very dissapointed, but in principle it can be done I think.

kclo4 - 14-5-2005 at 07:47

Would ammonium hydroxide work? The reaction would be CH3Cl + NH4OH = CH3NH2 +H2O + HCl since it makes HCl it would then react with the CH3NH2 and make CH3Cl and NH3Cl


Were did the other post go that says CH3Cl + NH4 compound would work in solution

[Edited on 14-5-2005 by kclo4]

cyclonite4 - 14-5-2005 at 08:36

Quote:
Originally posted by kclo4
Would ammonium hydroxide work? The reaction would be CH3Cl + NH4OH = CH3NH2 +H2O + HCl since it makes HCl it would then react with the CH3NH2 and make CH3Cl and NH3Cl


CH3NH2 is methanamine, not nitromethane. And that reaction would be more correctly:
CH3Cl + NH3 ----> CH3NH2 + HCl
Generalised:
Haloalkane + Ammonia ----> Amine + Hydrogen Halide

EDIT: Spelling
-and-
If an acid were to react with an amine, it would form an amine salt, e.g.
CH3NH2 + HCl <---> CH3NH3+Cl-

[Edited on 14-5-2005 by cyclonite4]

kclo4 - 14-5-2005 at 12:09

CH03NH2 can be oxidized by H2O2 to make CH3NO2

[Edited on 14-5-2005 by kclo4]

kclo4 - 14-5-2005 at 21:28

Could this reaction work and if not why not?
CH4OH + NH4Cl = CH3NH2 + HCl + H2O

12AX7 - 14-5-2005 at 22:07

I would suspect not as ammonium is a stable ion and would prefer the Cl, unless you can get the methylamine/methlammonium to precipitate, or something.

Tim

sparkgap - 18-5-2005 at 08:53

I see no reason for ammonium ion to readily cleave a nice and stable C-O bond.

That, and -OH is a poor leaving group.

sparky (~_~)

froot - 18-5-2005 at 11:47

I made CH3NO2 by dissolving about 20g NaNO2 (I'm sure KNO2 would work) in a mixture of 100ml methanol and 100ml water, and then adding 100ml 50% H2SO4 dropwise from a sep funnel. the gas that bubbles off is CH3NO2. The reaction is immediate being why I add the acid slowly.
The amounts mentioned are not accurately worked out, just a thumbsuck which worked fine in this case.

chemoleo - 18-5-2005 at 13:08

froot, you realise you made methylnitrite CH3ONO, and not nitromethane CH3NO2?

Blind Angel - 18-5-2005 at 17:25

the Niromethane method on syntethikal use a two step method very similar:
MeOH + H2SO4 -> MeHSO4
MeHSO4 + NaNO2 -> MeNO2

(very big picture)

It might be possible to make it one pot?

froot - 18-5-2005 at 23:41

OOOPS!! :o

And here I was thinking that nitromethane was CH3ONO2. Sorry Chemoleo

alchemie - 21-5-2005 at 04:58

Quote:
Originally posted by Blind Angel
the Niromethane method on syntethikal use a two step method very similar:
MeOH + H2SO4 -> MeHSO4
MeHSO4 + NaNO2 -> MeNO2

(very big picture)

It might be possible to make it one pot?


Actually there are very important differences between the two methods.

The method you are refering to consists in the solventless reaction between NaSO4CH3 and NaNO2. Wich yields nitromethane. This is different from the method root used, in wich H2SO4 is added to an aqueous solution of NaNO2 and methanol. This yields methyl nitrite.


This reaction:
MeOH + H2SO4 -> MeHSO4 + H2O
needs anhydrous conditions and would never occur in an aqueous solution. Actually, forming the methyl sulphuric acid is accomplished in methanol solution, with the aid a drying agent, like Na2SO4, to remove the water formed in the esterification of the acid.
The second step, formation of nitromethane from NaMeSO4 and NaNO2, also has to be done with exclusion of water, for the same reasons: hydrolysis of the sulphuric ester.

The reaction between NaMeSO4 and NaNO2 needs relatively high temperatures, wich requires heating the intimately mixed solid reagents. These reasons preclude the use of a solvent, making the one pot impossible.

S.C. Wack - 21-5-2005 at 11:28

Not exactly.

Search WD.

The_Davster - 21-5-2005 at 21:01

It should be noted that methylsulfuric acid can be used as a chemical weapon...

EDIT: changed 'is a chemical weapon' to 'can be used as a chemical weapon'

[Edited on 22-5-2005 by rogue chemist]

Borek - 25-5-2005 at 04:27

What I don't get from the whole thread is:

nitrocompounds are derivatives of the nitric acid, yet you want to prepare nitromethane from nitrite, not nitrate.

How come?

Smarkotan oz gluthozmaz

[Edited on 25-5-2005 by Borek]

Blind Angel - 25-5-2005 at 14:45

Nitromethane is MeNO2
MeNO3 (the one prepared with nitrate) is Methyl Nitrate

Borek - 26-5-2005 at 15:04

Quote:
Originally posted by Blind Angel
Nitromethane is MeNO2
MeNO3 (the one prepared with nitrate) is Methyl Nitrate


That's not what I am referring to. Methyl nitrate is an ester and that's something totally different.
Take nitrobenzene - to prepare it you use mixture of sulphuric and nitric acid. Why? Because you need N(V) from nitric acid. I would expect that to produce nitromethane you need N(V) as well, not N(III).

kclo4 - 27-5-2005 at 16:33

How can you make NaSO4CH3 I goggled it and found three sites with no information on it, or how to make it?

Blind Angel - 28-5-2005 at 09:26

Look on synthetikal, there is an easy and detailled work-up posted there.

tetrachloromethane - 27-6-2005 at 14:39

It is made commercially by reacting nitric acid vapor and methane at 400C. If the two reactants were mixed and passed through a very hot borosilicate tube, the resulting vapor could be condensed by a double jacket condenser. The only problem would be reaction rate. I'm not so good with chem kinetics, so could someone with greater knowlege in this area speak up?

wertfun - 6-12-2005 at 10:54

I just ask how come sometimes nitromethane is MeNO2 and sometimes it is CH3NO2?:o

Douchermann - 6-12-2005 at 13:44

They are the same thing, Me is an abbreviation for Methyl. Methyl is the CH3 group you see there. Would it be possible to produce nitromethane by bubbling methane through nitric acid with a catalyst present? If so, what catalyst would be a good one.

epck - 6-12-2005 at 15:02

I've heard this can be done to produce nitroethane, the following is from the rhodium nitorethane FAQ:

"Method 14: Vapor Phase nitration of propane.

The propane is bubbled through nitric acid heated to 108°C and lead into a reactor at 420°C.the product is then condensed and fractionated.(26% nitroethane formed)

Industrial and Engineering Chemistry, Vol 28, Mar, 1936. Pg 339-344.
JOC, Vol 17, pg 906-944.

Method 15: Vapor Phase nitration of ethane.

Same as propane but at least 80% yields.

Industrial and Engineering Chemistry, Vol 28, Mar, 1936. Pg 339-344.
JOC, Vol 17, pg 906-944. "

I would assume, possibly incorrectly, that the same reaction would hold true for methane. However I have not tried either reaction.

chemoleo - 6-12-2005 at 15:07

Another thing I wondered, would diazotation be possible?
I.e. from methylamine, convert to the azo form and use NaNO2 to get nitromethane.

Any ideas? Or does diazotation and substitution only work with a select range of ions? (Cl, CN, etc)

The_Davster - 6-12-2005 at 15:23

I have not seen any mention anywhere regarding substituting a diazo group with a nitro before unfortuantly.:(

Well today I came across a mention that the vapour phase nitration of methane with nitric acid occurs around 460C, not that easy of a temperature, but not completly out of reach either. Also, vapour phase nitration of alkanes higher than methane will always produce nitromethane as a byproduct, but by the time you reach either propane or butane the percentage of NM formed is only around 2%. Seeing as these are radical reactions with nitration of butane, for example, you would get a mix of nitrobutane, nitropropane, nitroethane, and nitromethane.

sparkgap - 6-12-2005 at 19:51

"Another thing I wondered, would diazotization be possible?"

It's possible, but gnarly. The resulting methyldiazonium ion would be really keen to decompose into the methyl carbocation and nitrogen, so that would present you with a possible explosion risk.

Otherwise, the methyl carbocation would take on any nucleophile within reach, so I'd think this diazotization shouldn't be done in aqueous medium unless you want methanol also...

sparky (~_~)

Another synthesis route

chemoleo - 6-12-2005 at 20:18

I'm not sure whether this has been mentioned elsewhere, if so let me know.

Apparently, nitromethane can also be made by warming sodium chloroacetic acid in an aqueous solution with a stoichiometric amount of sodium nitrite NaNO2.
The resultant MeNO2 is separated by steam distillation (bp 120 deg C).
The reaction was first described by Kolbe.

However, the yield is 35-38%

However, if chloro-acetic acid can be made easily, I'd probably go for that reaction.... seems most straightforward, despite the bad yield!

I tried to search this forum on CAA, but only found this thread. It appears Polverone had a go at it with trichloroethylene and H2SO4 reflux?
Is direct chlorination of HAc possible?

Edit: Silly me, it's on OrgSyn!
Detailed conditions, that's all we need! NOw there remains an easy chloroacetic acid prep!

PS Sparkgap/rogue, you are indeed correct. I did some checking... and it's definitely not suitable.

[Edited on 7-12-2005 by chemoleo]

Chris The Great - 7-12-2005 at 00:12

I remember reading a journal posted here about this reaction also decomposing the nitromethane, hence the low yield. It then went on for a higher yield reaction. Of course, I was busy at the time, didn't read it, and forgot about it until now. But if anyone remembers that article...

Chloroacetic acid is pretty easy if you have phosphorus. Basically, Cl2 + glacial acetic acid with P catalyst. Sulfur apparently works but poorly... No other details, but Vogel has detailed procedures for both these reactions.

It also mentions adding a NO2 group by diazotation, using NO2BF4. It mentions a possible explosion risk... I doubt it would be stable to react in this case, in Vogel it was used as an example for preparing pure isomers of aromatic compounds (for example pure 1,2 dinitrobenzene).

garage chemist - 7-12-2005 at 04:22

Chloroacetic acid synthesis can be found here:
http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/c...

I think I'll try it some day. As the light source I'll use a 500 watt halogen light, with the front glass removed (normally filters out UV).

kclo4 - 28-12-2005 at 19:00

Well i just read that chloropicrin reacts with NaOH and water to form sodium nitroacetate and sodium chloride. Here:
http://www.erowid.org/archive/rhodium/chemistry/nitroalkane....
it says the sodium nitroacetate is very unstable and reacts with water to make sodium bicarbonate and nitromethane! so making nitromethane should be easy, after you make the solution you could add a lot of salt to make the nitromethane come out of solution and float to the top, then it can be taken out with a sepetory funnel. I think this method would have good yields and maybe a good route to go with if one needs nitromethane. dose anyone have a comment on making nitromethane this way?

I don't know if this is any help but what could it hurt to mention?

Fulcanelli - 7-1-2006 at 11:09

I made nitromethane sucessfull by this way:

- Mix 100g chloroacetic acid & 200ml H2O
- Neutralize the solution with Na2CO3 (slowly, there will be a lot of CO2)
- Mix with a (freshly prepared) soln. of 70g NaNO2 (sodium nitrite) in 120ml H2O
- Distill (carefull, slightly exothermic reaction)

The distillate will be mainly water containing the MeNO2 (unsolouble). If no more MeNO2 comes over, the reaction is finished.

- Separate the phases of the distillate
- Saturate the aqueous layer with NaCl and distill off some more MeNO2.
- Extract the distillates with DCM
- Evaporate the DCM and dry the MeNO2 with CaCl2

Yield will be 50-60ml MeNO2. Sounds not so much, but if you need it for 2C-H production it's quite a lot...


This works too for Nitroethane, but the yields are low and the reaction more exothermic, so be careful if you try it.

bio2 - 9-1-2006 at 00:29

........Could this reaction work and if not why not?
CH4OH + NH4Cl = CH3NH2 + HCl + H2O ....

Assuming that you meant MeOH + NH3.HCl
then yes this method will work at 300 C using
Ferric or zinc chloride as catalyst/dehydrator in a sealed vessel.

The product is the amine hydrochloride.

METHYL AMINES FROM METHYL ALCOHOL AND
AMMONIUM CHLORIDE.’
BY W. D. TURNEK AND A. M. HOWAI,D.
Received September 30, 1920.

US2085785 is a patent using the same method.

On another note, regarding nitroalkane synthesis from
Na alkyl sulphates and NaNO2. This can be done in aqueous solution and yields are even better than the dry procedure if
properly done!

The_Davster - 14-1-2006 at 14:58

Quote:
Originally posted by chemoleo
NOw there remains an easy chloroacetic acid prep!


Hmm...Could chloroacetone undergo the haloform reaction with NaOCl leaving Na-chloroacetate?

I also wrote down from somewhere, although I have forgotten where, that:
Chloroacetone + NaNO2--> nitroacetone
nitroacetone +NaOH-> nitromethane.
And:
MeOH + p-toluene sulphonic acid ->methyl tosylate
methyl tosylate +NaNO2--> NM +sodium tosylate(I imagine can be recycled)

[Edited on 14-1-2006 by rogue chemist]

EDIT: On second thought, would chloroacetone react with NaOCl to make carbon tetrachloride? That would be interesting..

[Edited on 16-1-2006 by rogue chemist]

The_Davster - 3-2-2006 at 22:30

Quote:
Originally posted by rogue chemist

Hmm...Could chloroacetone undergo the haloform reaction with NaOCl leaving Na-chloroacetate?



Yes!

I added 1mL of chloroacetone to 25mL ~10% NaOCl. The solution instantly qent cloudy and after 30 min there was left a turbid upper layer and a very small lower layer of what smelled like chloroform.

The chloroform was pipetted out and to the remaining solution was added 2g of NaNO2 in 40mL dH2O, this was transfered into a 500mL RBF with a condenser on top and inside the condensor was a thermometer resting on the bottom of the flask( I don't have a 2 neck flask, I improvised). The temp was slowly brought up to 80C with an alcohol burner and the colour of the mix turned yellow, at 85C bubbles of what is suposed to be CO2 was given off, however upon removing the burner the reaction was not self sustaining like in the procedure on orgsyn. The mix was brought up to 100C over the next 3 min and kept there for a couple of min untill the effervescence of CO2 had stopped and the rxn was simply boiling. Adding a drop of water into the reaction produced a localized turbitity in the yellow, it looked as if something other than water and salts were in there (hopefully NM!).

The entire mix was allowed to cool to room temp and was poured into 75mL of ~10% NaOCl. I was testing for the presence of nitromethane by attempting to make chloropicrin with it as chloropicrin has a much lower solubility than NM, about 10x less. No reaction was noticed(at least not like in Haggis' vid Garage experiments with PS), other than the yellow colour slightly dissipating. I will smell tomorrow the mix, see if any chloropicrin has formed, at a solubility of ~0.1g/100mL it is entirely possible that it dissolved completly. The scale I did this experiment at was perhaps a bit small to get observable product, and the fact that I did not purify my chloroacetate or any other intermediates.

Nicodem - 4-2-2006 at 01:35

There is no theoretic base for such a reaction as the formation of sodium chloroacetate from chloroacetone and NaOCl. As the chloromethyl group's hydrogens are the most acidic it would obviously get oxidized to -CCl3 and subsequently hydrolyzed to CHCl3 and the acetate.
Chloroacetone is also formed from acetone and NaOCl as an intermediate but its further chlorination to 1,1-di- and 1,1,1-trichloro-acetone is considerably faster than its formation so it can not be isolated in chlorinations in basic media (such as NaOCl solutions are).

See the mechanism of the haloform reaction:
http://www.organic-chemistry.org/namedreactions/haloform-rea...
http://www.mhhe.com/physsci/chemistry/carey5e/Ch18/ch18-3-2b...
and many other web pages.

[Edited on 4-2-2006 by Nicodem]

Chris The Great - 4-2-2006 at 18:42

I guess you would need 1,3-dichloroacetone as opposed to just chloroacetone. Chlorination (Cl2) would first give chloroacetone, and then a mix between 1,1 and 1,3 dichloroacetone. Add to NaClO and get chloroform and sodium chloracetate. All these compounds are toxic and irritants so great ventilation would be a must I would think.

The_Davster - 4-2-2006 at 19:10

I stopped that attempt, after 24h no chloropicrin smell was detected, so that method is not workable.

I am currently trying in the garage chloroacetone+ NaNO2 --> nitroacetone and then nitroacetone +NaOH--> nitromethane.

I am just curious if these reactions work, theres no way I will scale up and use large ammounts of chloroacetone. Lets just say my prep of chloroacetone was not so fun as I did not wash my glass after the rxn well enough with enough NaOH solution....
After I am done with my ~6g chloroacetone I will not likely make more.

Nicodem - 5-2-2006 at 03:19

Rogue chemist that is certainly a good idea to prepare nitroacetone this way. I have been thinking of that a while ago though in the context of 3-chlorobutan-2-one. However I never was so motivated to search for the literature and I’m not so sure the alpha-nitroketones hydrolyze so easily (as for example the –CO-CX3 groups). Do you have any relevant references? I would be interested to hear what you found.

In case you might want to prepare some more chloracetone, the preparation as described in FR2633614 is very easy and I had no troubles in the preparation of a 100g batch (only a couple of tears:o). After the reaction you just add a pinch of Na2CO3 to neutralize the catalytic amount of H2SO4 used, vacuum filter the cyanuric acid precipitate, wash it with some more acetone, and then distill the filtrate in a fully closed system in a fume hood to get the recycled acetone and the higher boiling chloroacetone. It is advisable to redistill the product to get it pure or alternatively use a distillation column. If it is not redistilled it gets dark in few weeks. The yield after the redistillation was 75%.
The only point when you can get in troubles by exposing to chloroacetone is when you wash the glassware and if you don’t have a gas mask you better dismantle and leave it outside for the irritating chloroacetone to evaporate. Also it is very important to cool the reaction in an ice bath as described in the patent since it is quite exothermic and if it runs out of control to a boiling point, well then you are in really big troubles…

The_Davster - 6-2-2006 at 16:13

I am afraid my references to that reaction are rather obscured in my memory. It was one of those days at uni where I wander the chem section at the library and grab random chem books and spend several hours pouring over then. From what I remember it was only mentioned in passing as "nitroacetone can be cleaved by base to yield nitromethane and sodium acetate" This reaction was also mentioned in passing in an old thread on roguesci.
As for the synthesis of the nitroacetone I am not really basing it on much more than the synthesis mentioned in PATR 2700 which used silver nitrite and iodoacetone in ether at 0 degrees C.

I made a solution of 1.2g NaNO2 in ~10mL dH2O and added 1mL of the chloroacetone to it. I have been swirling the testube every once and a while the last day or so and both layers in the testtube have gone yellow(the chloroacetone was colourless to begin with). I know this set up is rather crude with both reactant and product being insoluble in H2O, but I lack ether or DMSO, both of which I would like to try at some point.

I used the process off that french patent as well to make my chloroacetone, Orgie started a thread about it a couple of years ago or so. Everything was fine till it came time to wash the glass, I just did not wash it with enough NaOH first...

My chloroacetone is about a month old now, it is still clear(I think there is some acetone contaminats though) after only one distillation.

"then distill the filtrate in a fully closed system in a fume hood" Lets just say without the fumehood I am not doing this again, especially a larger batch. Outdoor experimenting is not an option currently....

[Edited on 7-2-2006 by rogue chemist]

The_Davster - 25-2-2006 at 18:55

After 2 weeks of the chloroacetone sitting in contact with a sodium nitrite solution in the garage, with the temp ranging from -30 to 10C outside, the solution is yellow, and still 2 layers. Taking a small sample of a mix of the phases and adding it to a NaOH solution produced only a light pink solution, unlike the bright cherry red of pure chloroacetone. So I figure it has nearly all reacted, a bit more time out there should do it I hope. It will then hopefully be cleaved into nitromethane and nitromethane's presence will be tested by forming chloropicrin. Seeing as some acetone may be in my chloroacetone, the formation of an insoluble liquid after the nitromethane is treated with bleach is not enough to determine whether what I have is NM so I guess I will have to do the sniff test;).

Nitroketone preparation and cleavage

Nicodem - 28-2-2006 at 11:19

I searched SciFinder and Beilstein and found some relevant references.

The nucleophylic substitution of alpha-haloketones with the nitrite is apparently possible, however I found no reference for alpha-chloroketones. There were only a couple of references for alpha-bromoketones of which the most thorough and interesting is:
Munz, R.; Simchen, G.; Liebigs Ann. Chem. (1979) 628-638.
They use PTC conditions (NEt4NO2/CH2Cl2) and report several examples ranging from 3-bromobutan-2-one to 2-bromo-2-methyl-1-phenylpropan-1-one and similar.
The other is a patent, US4035512 (also FR2274287 or DE2525512), where a substituted alpha-bromotetralone is used successfully to yield the appropriate alpha-nitroketone with NaNO2/DMF in presence of fluoroglucinol (an alkyl nitrite scavenger).

For the cleavage of alpha-nitroketones to the appropriate acid and nitroalkane there are many references but almost exclusively for 2-nitrocycloalkanones. I have no idea why is it so. I would expect the cleavage would be possible with the acyclic nitroketones as well, but I only found two references and both are archaic to say the least. In both these cases the ketone had additional groups that make the carbonyl more electro deficient by electrowithdrawal. The first mentions the cleavage of alpha, para-dinitroacetophenone to nitromethane and the second of Ph-CH(NO2)-CO-C(Ph)=C(Ph)-COOH to phenylnitromethane:
Thiele; Haeckel; Justus Liebigs Ann. Chem. 325 (1902) 10.
Cohn, G.; Chem. Ber.; 24 (1891) 3867.
The conditions for the ring opening of 2-nitrocycloalkanones seams quite simple and require a mildly basic aqueous solution of a base (diluted NaOH or NaHCO3), nonaqueous conditions with KF as a base or acidic conditions (Amberlist resin in MeOH, yielding an ester instead of carboxylic acid). Two papers are included in the attachment and there is also a patent on it, US4554387.

There is also a method to form alpha, alpha-dichloro-nitroalkanes with NaOCl directly from cyclic nitroketones. The paper is also included in the attachment.

Attachment: nitroketones.zip (621kB)
This file has been downloaded 886 times

The_Davster - 14-5-2006 at 10:22

So I finally returned to my testtube of chloroacetone and nitrite....
It was a light yellow, with a white crystalline ppt on the bottom. There was no insoluble layer of chloroacetone left. I decanted the liquid in the testtube into a solution of 0.6g NaOH in~20 mL H2O in a 50mL erlenmeyer. The solution instantly turned a rather dark yellow colour. No red therefore no chloroacetone was left. The ppt from the testube was tested for chloride with silver nitrate, the ppt was just salt. So I know the nitrite did react with chloroacetone leaving salt and *hopefully* nitroacetone. Hopefully my long rxn time at ambient temp(-30 to 20) did not cause loss of nitroacetone.

In reterospect I should have used a stronger NaOH solution today to attepmt cleavage of the nitroacetone as nitroacetone likely will not cleave as easily as trichloroacetone into chloroform. I will add more base in a few days if I think its necessary.

The_Davster - 22-5-2006 at 17:04

The 'nitroacetone' and NaOH has really darkened over the last few days. Yesterday I added half of it to 10% bleach, no separate layer formed and no chloropicrin smell occured.

guy - 7-6-2006 at 17:48

Just wondering, why can't a regular nitration of methanol work?

The_Davster - 7-6-2006 at 18:24

Methyl nitrate =/= nitromethane

CH3ONO2 vs CH3NO2

guy - 7-6-2006 at 18:54

Wouldn't a nitration produce a nitro compound, not a nitrite ester? But anyways I found the answer, it is because aliphatic nitro compounds are unstable in acidic environments.

The_Davster - 7-6-2006 at 19:03

Quote:
Originally posted by guy
Wouldn't a nitration produce a nitro compound


Not when technically it is the esterification of an alcohol with the nitronium ion. C-NO2 only occurs on aromatic rings by SeAr.

Aliphatic nitro compounds may be unstable in acidic medium, but that is not the reason you get C-ONO2 not C-NO2. What would NO2+ attack in a methanol molecule? Carbon with its partial positive charge, or the big partial negative charge on the oxygen? In aromatic nitration either o and p or meta have a partial negative charge, so the nitronium attacks there.

I am not sure I am explaining this coherently though.

guy - 7-6-2006 at 19:26

O I see now. For some reason I was thinking the carbon had a negative charge, duh.

Then how does the chloroacetic acid route supposedly work? Would not the oxygen in nitrite attack the carbocation?

[Edited on 6/8/2006 by guy]

The_Davster - 7-6-2006 at 19:58

Some sort of rearrangement follows, I am not really sure on how exactly it works. I know that when an alkyl halide is treated with nitrite that first the alkyl nitrite is formed, which is volatile so some evaporates reducing yields, but the remainder rearranges to nitro.

Nicodem - 7-6-2006 at 23:59

There is no rearrangement involved. A nucleophilic substitution with the nitrite yields both the nitroalkane (R-NO2) and alkyl nitrite (R-O-NO). The ratio of these two products depends on the conditions, but a problem is also in that the alkyl nitrites react with nitroalkanes thus reducing the yield (thus phluoroglucinol or other alkyl nitrite scavengers are usually used for proper yields). The reason why you get two products (R-NO2 and R-O-NO) lies in the ambident properties of the nitrite anion (NO2-). The negative charge can resonate between two forms, one having the (-) on the oxygen and the other on the nitrogen. Thus the product ratio depends on which will be faster to react with the elctrophile (R-X) and this is highly dependent on the nature of the counter ion, solvent and the electrophile.
Quote:
Originally posted by guy
Wouldn't a nitration produce a nitro compound, not a nitrite ester? But anyways I found the answer, it is because aliphatic nitro compounds are unstable in acidic environments.


Nitration of alcohols gives alkyl nitrates (R-O-NO2). For obtaining nitroalkanes (R-NO2) one has to nitrate alkanes with HNO3, NO2 or other suitable reagents, but the conditions required are pretty harsh (300°C, for example).
Aliphatic nitro compounds are extremely stable in acidic environment. You can mix nitromethane with strong acids like AlCl3 or H2SO4 and it won’t affect them. On the other hand, if you first prepare a nitronate salt (like MeNO2 + NaOH -> NaO-NO=CH2) and then add acid a certain form of oxidative hydrolysis occurs, the so called Nef reaction. But the nitronate salt is not the same as nitroalkane.

neutrino - 8-6-2006 at 14:40

>For obtaining nitroalkanes (R-NO2) one has to nitrate alkanes with HNO3, NO2 or other suitable reagents, but the conditions required are pretty harsh (300°C, for example).

What do you make of this, then?
Quote:
Standard gasoline, get the cheap stuff and not gasahol (gas/ethyl alcohol mix) if you can avoid it, is added gradually to a mixture of 15 parts 100% sulfuric acid and 3 parts 100% nitric acid in a large beaker. Add 1 part of gasoline per 18 parts of mixed acid. The reaction temperature should be somewhat cool, never let the temperature rise above 80 °C. A temperature below 20 °C should do, you can regulate this with a salt-ice bath. When the nitration is completed, the mixture is diluted with a large quantity of cold water to precipitate the product. The un-nitrated oil will float to the top of the acid-water solution. Collect the precipitate on a filter and wash with water, yield will be 30% to 90% depending on the crude oil used to manufacture the gasoline. You will need a graduated cylinder for measuring liquids, and a thermometer to monitor the temperature.


It looks like a low temperature nitration with ordinary mixed acids. Then again, this procedure may have been done with oils with high aromatic contents, different from today's mainly aliphatic gasolines.

Nicodem - 9-6-2006 at 00:36

That procedure is obviously meant to nitrate the aromatic fraction of gasoline. Though, it should talks about crude oil as some have a very high content of the aromatics (normally about 20%, but some exceptions like some petroleum from Siberia even up to 60%!). I think today that procedure is quite obsolete, since the new regulations (like the 1990 Clean Air Act Amendments in USA) make it mandatory to reduce the aromatic content (especially benzene and polyaromatics) in gasoline to minimum. I wander if it was even tried on today’s gasoline as described above.
Anyway, aromatic nitration by electrophilic substitution like this is way different than radical nitration of alkanes in gas phase (where H2SO4 does not help).

Vitus_Verdegast - 9-8-2006 at 17:26

These are the papers on vapour phase nitration by the G. Bryant Bachman group (J Org. Chem. 1952, 7, 17, p. 906-954) :

http://rapidshare.de/files/28835243/Nitration_Studies._I._Ge...

http://rapidshare.de/files/28835403/Nitration_Studies._II._E...

http://rapidshare.de/files/28835491/Nitration_Studies._III._...

http://rapidshare.de/files/28835555/Nitration_Studies._IV._E...

http://rapidshare.de/files/28835657/Nitration_Studies._V._Ef...

Sandmeyer - 11-11-2006 at 06:48

There are a couple of threads on nitroethane production and since this is the longest one I'll post in here.

D. Kim and co-workers have published an interesting total synthesis of interesting structure (-)-brefeldin A in which a key step is an intramolecular nitrile-oxide cycloaddition. The substrate for this step was prepared via a double Finkelstein reaction, first an alkyl tosylate was turned into iodide, then the iodide was swaped with a nitrite to give nitroalkane. Interesting step for this discussion is that going from alkyl iodide to nitroalkane. It was done using NaNO2, urea and DMSO as solvent under room temperature for 15 h giving the nitroalkane in 75% yield, these conditions obviously don't give isomeric alkyl nitrite...

(3) Iodination. A mixture of the above tosylate (107 mg, 0.25 mmol) and sodium iodide (753 mg, 5.02 mmol) in 2-butanone (12 mL) was refluxed for 1.5 h. After removal of the solvent, cold water was added to the residue. The mixture was extracted with EtOAc (30 mL x 3). The combined organic layers were washed with saturated Na2S2O3 solution, saturated NaHCO3 solution, and brine, dried over anhydrous MgSO4, and concentrated in vacuo. The resulting residue was purified by column chromatography on silica gel (EtOAc/ hexane, 2:3) to give the iodo compound (94 mg, 98%) as a colorless oil [analysis data left out]

(4) Conversion to Nitro Compound. To a solution of the above iodo compound (93 mg, 0.24 mmol) in DMSO (4 mL) were added urea (101 mg, 1.68 mmol) and sodium nitrite (83 mg, 1.20 mmol) at room temperature. After 15 h, the mixture was poured into water and extracted with EtOAc (30 mL x 3). The combined organic layers were washed with water, dried over anhydrous MgSO4, and concentrated in vacuo. The resulting residue was purified by column chromatography on silica gel (EtOAc/hexane, 2:3) to give nitro compound 17 (54 mg, 75%) as a colorless oil. [analysis data left out]

Asymmetric Total Synthesis of (+)-Brefeldin A from (S)-Lactate by Triple Chirality Transfer Process and Nitrile Oxide Cycloaddition

Kim, D.; Lee, J.; Shim, P. J.; Lim, J. I.; Jo, H.; Kim, S.

J. Org. Chem.; (Article); 2002; 67(3); 764-771. DOI: 10.1021/jo010743i

Full-text: http://rapidshare.com/files/2917645/brefeldin.pdf.html

Of course, making nitroethan itself is stupid idea, there are other routes to amphetamines...

[Edited on 11-11-2006 by Sandmeyer]

jim20/20 - 11-11-2006 at 11:19

Quote:
Originally posted by Sandmeyer
Of course, making nitroethan itself is stupid idea
[Edited on 11-11-2006 by Sandmeyer]


for sure by this method
4l of dmso to get 54g of ne if the ratios are crucial
urea replaces phloroglucinol in this method and possibly is not so soluble in dmso

Sandmeyer - 11-11-2006 at 12:29

Of course, I agree, I don't know of any kitchen-friendly method to make it, nor do I see a reason to do so. If one can't get it it's time to look outside the Henry condensation box.

hector2000 - 1-6-2009 at 03:21

Patent number# 4319059

Quote:

To a mixture of magnesium methoxide (0.11 mole) and dimethyl sulfoxide (50 ml) α-bromopropionic acid (0.11 mole) ws added at 20° C. with stirring. To this mixture a solution of sodium nitrite (0.145 mole) in dimethyl sulfoxide (65 ml) was added at room temperature. Then, the reaction mixture was stirred at room temperature for 6 hours and was neutralized upon addition of diluted hydrochloric acid. The product was analyzed on a 3'×3/16" Porapak Q column for nitroethane at 150° C. and on a 3'×3/16" column packed with 10% ethylene glycol adipate and 1% phosphoric acid on Chromosorb AW 80/100 mesh for α-bromopropionic acid at 150° C. This analysis of the reaction mixture indicated more than 99% conversion of α-bromopropionic acid and 94.5% yield of nitroethane

α-bromopropionic acid is 2-bromopropionic acid ?
Yield is acceptable?94.5% :o
Attachment: US4319059.pdf (94kB)
This file has been downloaded 887 times

[Edited on 1-6-2009 by hector2000]

benzylchloride1 - 17-6-2009 at 14:26

Does anyone have the procedure for the synthesis of nitromethane from methyl sulfuric acid? I searched for the Synthetikal site, but it currently does not exist.

DJF90 - 17-6-2009 at 17:07

I would assume it to be similar to the rhodium prep for nitroethane, but adjusting the amount of carbonate to take into account for the free acid;

"1.5 mole sodium nitrite (103.5g) is intimately mixed with 1 mole of sodium ethyl sulfate (158g) and 0.0625 moles of K2CO3 (8.6g). The mixture is then heated to 125-130°C, at which temperature the nitroethane distills over as soon as it is formed. The heating is discontinued when the distillation flow slackens considerably, and the crude nitroethane is washed with an equal amount of water, dried over CaCl2, and if needed, decolorized with a little activated carbon. The nitroethane is then re-distilled, collecting the fraction between 114-116°C. Yield 46% of theory."

However this is just a suggestion, I would expect you to check it over before blindly stumbling forward :P

[Edited on 18-6-2009 by DJF90]

benzylchloride1 - 18-6-2009 at 11:19

Thank you very much for the preparation, DJF90. I am going to try the nitroethane synthesis first, I plan on using the nitroethane for the preparation of some cryptan ligands. Nitromethane can be used to make similar ligands. I am working on the sodium ethyl sulfate synthesis; I am using the method from Cohens Pratical Organic Chemistry, the author claims that from 87ml of ethanol, 45-50 grams of the salt can be prepared. I tried this synthesis several years ago, it was a failure because I poured the hot reaction mixture directly into water instead of cooling it. Ethyl hydrogen sulfate rapidly hydrolyses in acidic hot water. I will report back when the synthesis of the sodium ethyl sulfate is complete.

benzylchloride1 - 19-6-2009 at 12:50

Sorry for the double post.
I attempted the sodium ethyl sulfate synthesis and obtained nothing beside a few crystals that when treated with hydrochloric acid produced carbon dioxide like sodium carbonate. I evaporated the solution that was thought to contain the product to around 100ml, no large scale crystallization, even after standing over night. The solution of ethyl hydrogen sulfate was cooled to 15 C before being poured into ice water. The solution was then neutralized with calcium hydroxide, filtered, the calcium sulfate was washed with hot water and then the mixture was treated with sodium carbonate solution until no more calcium carbonate precipitated. The solution was then filtered, the calcium carbonate precipitate washed with water and the solution concentrated from about 600ml to 100 ml. Even after adding methanol, very little precipitated. I decided to discard the mixture. Has anyone tried this preparation of sodium ethyl sulfate? I made several attempts at this several years ago. I wanted to make the sodium ethyl sulfate before the sodium methyl sulfate because I have a known procedure.

[Edited on 19-6-2009 by benzylchloride1]

Sedit - 19-6-2009 at 13:14

Benzylchloride im not exactly sure which synthesis you attempted but here is a one for Sodium Ethyl Sulfate I myself wanted attempt sometime soon but since you already seem to be in the swing of things perhaps you would not mind attempting this process posted by Evil_lurker some time back and letting us know how it goes.
Quote:

Nitroethane, that substance which is so cheap at any chem supply house, but so damn hard to get. Making the stuff ain't very much easier than buying it from the recipes on the net.

The two OTC easiest ways, using sodium ethyl sulfate and diethyl sulfate as reagents are very hard and dangerous to manufacture. The problem lies in the water molecule the ETOH creates when it forms the ester. The apparatus looks plain scary to operate, and creates diethyl ether as a side product and the yields suck ass!

But now that problem has been fixed. Sodium ethyl sulfate can be easily prepared in the home laboratory from common sodium bisulfate found in pool pH down and 95% pure grain alcohol, and baking soda or sodium carbonate found in pH up.113 parts by weight of sodium bisulfate and 20 parts by weight of pure grain alcohol are combined in a flask and brought to boiling upon which time the sodium bisulfate crystals disappear and sodium sulfate forms.When the reaction has been completed, the flask was is immersed in an ice bath and vigorously stirred until the tempurature rapidly goes below 32.3C.

The formed sodium sulfate is thus filtered out leaving an anhydrous ethyl hydrogen sulfate/ethanol mix.The excess ethanol is distilled off, and the ethyl hydrogen sulfate is neutralized with an appropriate quantity of sodium carbonate leaving sodium ethyl sulfate.Simple... thats all there is to it! The secret to how it works is the excess sodium bisulfate when rapidly cooled below 32.3C forms the decahydrate, or Glaubers salt, and this sucks the water out of the reaction.This is discussed futher in US Patent number 3,024,263.


If this is effective then I see no reason why the substitution of MeOH here would not form the desired sodium methyl sulfate.

DJF90 - 19-6-2009 at 15:06

This was posted some time before on sciencemadness. The patent is available on googlebooks:
http://www.google.com/patents?id=f15mAAAAEBAJ&printsec=a...

franklyn - 11-10-2009 at 01:31



Lower nitroparaffins are prepared by treating the corresponding C1-3 alkyl chlorides
with alkali metal nitrites in DMSO : CH3Cl + NaNO2 -> CH3NO2 , 85% yield
Takagi, U.; Tsumura, R.; Mazaki, T. Kokai Tokkyo Koho 79,125,604 (Cl. C07 C79/04)
(Sept.29, 1979); CA92, 110519H.
US patent 2105581 discloses this but in aqueous conditions and poorer yield.
This method from 1956 applies NaNO2 in Dimethylformamide _
http://www.sciencemadness.org/talk/files.php?pid=81599&a...
The proceedure given here -> http://www.orgsyn.org/orgsyn/pdfs/CV1P0401.pdf
is only good for 35 - 38 % yield. Quite a difference the choice of solvent makes.
CH3Cl should readily result from Methanol + Muriatic acid with a Lewis acid catalyst
Zinc or Aluminum predissolved in the HCl. Given that current price of CH3.NO2 motor
fuel is ~ $ 55 gal + shipping , the savings from homebrewed would only be modest.

Iodopicrin (CI3NO2) and silver nitrite (AgNO2) yield Tetranitromethane according to
Hantzsch, Ber., 1906 num 39, pg 2478 . I wonder if in DMSO Chloropicrin and NaNO2
could substitute ? Might this work with Chloroform , 1,1,1,Trichloroethane or
Tetrachloroethylene.to produce corresponding nitro compounds.

Related thread -> http://www.sciencemadness.org/talk/viewthread.php?tid=2995

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franklyn - 30-10-2010 at 09:06

The opening citation of the post above is actually of a patent written in Japanese , some , but not this one,
provide cursory english translations. Available in Japanese here online
http://www4.ipdl.inpit.go.jp/Tokujitu/PAJlayout.ipdl?N0000=6...
The english Abstract is in the pdf here _ Attachment: Preparation of Lower Nitroparaffins - Japan Pat.pdf (148kB)
This file has been downloaded 1455 times
the table depicted on the next to last page confirms the preparation produces nitromethane in up to 55 % yield
in 2 hours under mild conditions. As I speculated above this method may have wider applications as yet untried.

Another paper describing this approach that I must have gotten here but I don't know who to attribute it to.
=> Attachment: Preparation of Nitromethane from Nitrite in DMSO.pdf (303kB)
This file has been downloaded 1057 times

Additional patents to those cited in the post above, US 2117931 , US 3014972
US patent 4424385 also references subsequent patents from the same Japanese inventors above.
For convenience here are those Abstracts => Attachment: Preparation of Lower NIitroparaffins.rtf (4kB)
This file has been downloaded 754 times
- Apply the step by step procedure I have outlined on the opening page of the first attached pdf
to access these two english abstracts and related publications as these here below.
S56-169648
http://www4.ipdl.inpit.go.jp/Tokujitu/PAJlayout.ipdl?N0000=6...
S56-169649
http://www4.ipdl.inpit.go.jp/Tokujitu/PAJlayout.ipdl?N0000=6...

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