nitro directly from alcohol?

[Hansje]

There's an article on Rhodium's site (here:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/alcohol2nitro.html

) that suggests preparation of nitroalkanes by just mixing an alcohol, acetic acid and sodium nitrite in DCM and adding conc. HCl.
This sounds too easy to be true. Does it work? Anyone ever try this?
Hansje high in proteine and fibre!

[Moriarty]

I don't remember real well, but about 10 years ago I made nitromethane from methanol.  I think it was a typical nitration using Sulfuric Acid as a catalyst and Nitric acid.  There's about ten variations on this theme in a book called The Chemistry of Powder and Explosives.  No.  Wait.  Here's one I can give you right now, as Moriarty carries four O-Chem text books in his bag and can't resist posting this one.
               420 degrees
CH4 + HNO3 ---------------->CH3NO2 + H2O
Methane                      NitroMethane

I know that one's not practical, but it says 420 in it.  So, I posted it

Seriously, I know it can be done with Nitric acid and am not sure about the catalyst.  Probably none needed with Nitric acid and alcohols.  The one mentioning Sodium Nitrate and Acetic acid is most likely the best and should most likely work as Sodium Nitrate/Acetic acid is a common method of commercial nitration.

Rhod, doubt you really want that text book reference, but here it is: Introduction to Organic Chemistry, DePuy and Rinehart.

P.S.  It just dawned on me in my hungover state.  Sorry, Moriarty's a little slow today.  Using sulferic acid on primary alcohols will very likely produce some stranger and unwanted products.  If memory served it was kinda volitile and methyl ether would be the product.  Sorry about that bees.  No sulferic acid please.
Who wants to play cops and dope fiends?

[Rhodium]

Nitric acid (or sulfuric acid + nitrate salts) on methanol should give the explosive methyl nitrate (CH3-O-NO2), and not nitromethane (CH3-NO2)...

[Moriarty]

Like I said earlier today Rodium.  Feeling a little slow today.
Who wants to play cops and dope fiends?

[Antoncho]

Yes, SWIM tried the rxn you mention - unsuccessfully. There are some obvious, even from theoretical standpoint, obstacles in this method - however, it can and should bee optimized (SWIM couldn't do that, for purely financial reasons).

His practical xperiences, as well as theoretical musings, can bee found in

Post 199007

(Antoncho: "Re: nitro mechanism", Novel Discourse) and downwards from it in that thread.

Hansje - If you' re going to try doing it the way i suggested (w/some drying agent to remove formed water), it would bee most wonderful and potentially revolutionary experiment!

Antoncho

[Hansje]

Antoncho - thanks a lot for that thread! I completely missed it because I had the FSE looking for nitroethane, this being the compound of my, strictly academic, interest. Very interesting and instructive.
If SWIM is going to have any experimental dreams about this they better not be wet ones   , so much is clear.
That's not easy, because the ingredients SWIM has available (80% acetic acid, 29% HCl, 95% ethanol) are too wet to begin with. Luckily SWIM also has shitloads of MgSO4. Maybe he will give it a couple of tries.
Suggestions always welcome.
Hansje high in proteine and fibre!

[halfapint]

Some little buzzard tells me this synth may not work properly for the lower nitroalkanes. My often fallible intuition gives me no reason for this pessimism. Should it work for nitroethane, wouldn't our patent searching beez have reported it to us, in their searches for nitroethane procedures?

I have lately ventured into higher temperature reactions in glass, ever so cautiously out of concern for the glassware. Soon I may screw up my courage enough to attempt gas phase reactions, and nitroethane (in mixed nitroalkane products) from propane and nitrous fumes will top the list. An early attempt using copper tubing, got clogged, but fortunately recovery was made without disaster. (I know copper reacts with hot NO_x! But copper nitrate, heated, gives NO2 and CuO, so I was hoping an equilibrium would bee established, and it would work in copper.)
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.

[Antoncho]

Oh, the reason for this method not being patented is very, IMHO, simple: it's very unpractical from economic standpoint. Nitroalkanes are commonly industrially made by exactly that gas-phase nitration method, which is a hundred times cheaper.

Now, i wonder, if someone will ever give a proper try to that EtCl + NaNO2 in boiling water thing (patented for production of nitromethane - see

Post 200843

(Antoncho: "Nitroalkanes from Me/EtCl and aq. NaNO2!", Novel Discourse)) - SWIM didn't succeed w/it - but obviously, beecause he lacked a proper foaming agent. The rxn occurs in gas-liquid surface. I would also bet that some PTC would bee of invaluable help for it.

It is somewhat complicated in terms of apparatus, but a technically inclined bee like Half-a-Pint, e.g., can certainly manage it with ease

Anyway, sounds way better to me than vapour-phase nitration    

Antoncho

[Hansje]

halfapint - SWIM has just repeated your nitric fumes and propane through hot copper experiment. Not because he thinks he can do better, but just because he happened to have everything needed lying around.
Indeed the whole contraption clogged up within 5 minutes after NO2 fumes had started to evolve. The clogging was anticipated (thank you!) and SWIM was at a safe distance when the stopper blew off the flask with boiling nitric acid and a large brown cloud of nitric oxides disappeared in the opposite direction (thanks again!).
After a while SWIM took a good look at the beaker filled with ice water that had been bubbled with the proceeds of the reactor. He noticed an oily substance clinging to the walls of the beaker. He also smelled something - almost sweet but not quite.
Now it has been some time since SWIM has smelled nitro alkanes so he isn't sure, but what other oily substance could have formed from nitric acid, propane and copper?
Hansje high in proteine and fibre!

[halfapint]

Ouch! Think we better slow down on this one, Hansje. I thought my problem was too small a diameter of my tubing, but the small size is so convenient to work by hand, without a tubing bender. I was using ground glass joints on my glassware. When one of those things gives, you're in a heap of trouble. And when the air gets red, don't fix it, flee. A bee sent me some literature to review, so I'll get back to this when I've learned more.
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.

[Hansje]

This literature is very informative! I can already see what went wrong. Not clogging, but a runaway reaction due to to much heat.
Very good news is that this apparently can be done in aluminium, which is sturdy, easily engineered and a good conductor of heat.
If we can tackle the problems of temperature control and a controled vapourizing of nitric acid, I foresee a great advance in backyard industrial chemistry.
Hansje high in proteine and fibre!

[halfapint]

OK, Hansje. Let's just make sure, this advance is accompanied by a similar advance in backyard industrial caution. Red oxides of nitrogen are not just scary, they really hurt you.

Antoncho:
"if someone will ever give a proper try to that EtCl + NaNO2 in boiling water

Post 200843

(Antoncho: "Nitroalkanes from Me/EtCl and aq. NaNO2!", Novel Discourse)"

Wonder if diethyl sulfate or yr. sodium ethyl sulfate wd. function alternatively in this rxn. For that matter, would diethyl sulfate work in the room temperature rxn in DMSO? Think we're onto an easier path to diethyl sulfate, bubbling SO2 through CuCl2 sol'n in ethanol. See

Post 278794

(halfapint: "Re: Dimethyl/Diethyl Sulfate", Chemistry Discourse). Sodium ethyl sulfate, I'm hearing, is sleepy simple: neutralize sulfuric acid in excess ethanol with Na carbonate ("pH-Up") then strip off the ethanol. Ethyl chloride seems cheap and easy, but as a gas, once through and it's gone. Has let's say a low residence time in boiling water. In general, I consider gases as wasteful reagents.

"a proper foaming agent. The rxn occurs in gas-liquid surface. I would also bet that some PTC would bee of invaluable help for it."

Yeah. Trouble is, foam automatically means foaming space. That already means "backyard industrial advance" scale, not "fold up your lab and stick it back under the cabinet" scale. A general-purpose bubble builder is detergent and glycerine, but I don't think we want foam quite that persistent, so we should try dishwashing detergent and ethylene glycol (antifreeze) here.

Why do I visualize a pot of broken glass for this rxn? OK, dig -- the rxn takes place in the liquid-gas interface, right? The film of fluid which runs down a glass surface, has a maximal exposure to surrounding gas, like the surface of a bubble does. Foam seems inconvenient to handle, hard to control, but boiling nitrite solution in a pot full of glass shards (inert packing material: Raschig rings, glass wool, silica gel beads, potsherds, rocks) in a tall pot without the foam, I could feel more comfortable with gassing from alcohol boiled with HCl. Perhaps there's a middle ground, with just a little bit of foam in lots of rocks.

"It is somewhat complicated in terms of apparatus, but a technically inclined bee like Half-a-Pint, e.g., can certainly manage it with ease"

Gotta get a workshop. Got to have a dedicated space to work. Tired of breaking glass from lack of elbow room. Don't like building submarine-locker size apparatus.
a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.

[halfapint]

E-Z Nitroethane proposal.

https://www.thevespiary.org/rhodium/Rhodium/chemistry/nitroalkane.html

sez:

From Sodium Ethyl Sulfate [4]
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 nitromethane is then re-distilled, collecting the fraction between 114-116°C. Yield 46% of theory.

Here's a Boiling Water Reflux version.
(1) Alcohol and Sulfuric prep of ethyl hydrogen sulfate: drop sulfuric acid gradually into an excess of cool alcohol and stir.
(2) Add portionwise enough sodium carbonate to make it basic. Hint: until sodium bicarbonate you add as indicator quits fizzing, then one more portion.
(3) Sodium Ethyl Sulfate prep: Boil off the alcohol, until the sodium ethyl sulfate and its slight admixture of sodium carbonate are dry.
(4) Nitroethane production: Add (overall excess) sodium nitrite solution in water, then reflux into a packed column. 'Bout that long.
(5) Distill off water, optionally under reduced pressure.
(6) Fractionally distill off nitroethane, optionally under reduced pressure.

a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.

[Antoncho]

Sorry, Half-a-Pint, that probably won't work. I have a very strong intuition telling me it won't work - i could elaborate, but don't have time now. At least, Vitsh once told me that mixing wet NaNO2 and NaEtSO4 immediately generated some nitrous (NO2) smell, whereas w/dry reagents it starts to smell weakly of EtNO2.

Excuse me, but did yoou see my writeup on this method, dry version? It's pretty easy by itself, but i always wondered if one could improve the yield (maybee dramatically so) by taking advantage of the following gimmicks:

a) To your mixed NaNO2/NaEtSO4 add some EtOH and reflux for some time. Both reagents are slightly soluble in EtOH, so they will probably inter diffuse, thus providing a much larger rxn surface. Then EtOH is just distilled off.

b) Use microwave for (at least - even if the 'microwave effect' will bee of no use here) even and smooth heating. It's been SWIM's practice that someof his nitroalkane (MeNO2, in his case) decomposes/reacts from overheating somewhat on the falsk's walls.

The theoretical yield of EtNO2 from 100 gr pure NaEtSO4 is 50 mls...

And - i advise everyone to take advantage of SWIM's improved neutralization procedure - found in hydroquinone di-methylation thread by also me  - i've done it a coupla more times and assure you that it is quite possible to achieve 95%+ yield by proper neutralization of the acid in plain water/NaOH.

Please take note that it is required at least 24h standing for the H2SO4/alcohol/Na2SO4 mixture to react completely, SWIM let his stand for 4 days.


Antoncho