Nitroethane from Sodium Ethyl Sulfate, K2CO3, NaNO2

icecool · Insistent Chemist

What do you guys think about this:
NaNO2+HCl --> HNO2
HNO2 + MeOH --> MeNO2
Does this also work for EtNO2 production?

And what about MeOH+MeNO2 --> EtNO2
Since MeOH is basic and MeNO2 acidic it is an acid/base reaction.

Nicodem · Sun Apr 24, 2005 11:18 pm

Icecool, you seem to have a terrible fixation on esters of nitric acids, but what you (and we) want are the nitroalkanes. You seem to have them confused all.

Methyl esters of nitric acids:
Me-O-NO2 methyl nitrate (ester of methanol with nitric (V) acid, explosive liquid)
Me-O-NO methyl nitrite (ester of methanol with nitric (III) acid, it is a gas at RT)

Nitroalkanes:
Me-NO2 nitromethane (note the nitro group is connected directly to the carbon!)

So, your equation are OK, but what you wrote as MeNO2 is not nitromethane but methyl nitrite (Me-O-NO).

icecool · Insistent Chemist

I know now by nitrating those liquids (ethanol and methanol) you won't get nitromethane and nitroethane but methylnitrate and ethylnitrate.
But what about the NaNO2+HCl method.
And the acid/base method, they are both very slightly acidic and basic but isn't there a catalyst?

IndoleAmine · Dreamreader Deluxe

HNO2 is called nitrous acid. Esterification leads to nitrite esters R-O-NO - in contrast to nitric acid HNO3, giving nitrate esters R-O-NO2.

Both rxns you suggested are esterifications, not nitrations.

For a reaction like between a strong acid and base, protons have to be exchanged.
Neither is nitromethane a strong proton donor, nor is MeOH a good H+ acceptor.

No rxn will occur if you mix them, they are used together as FUEL for RACING CARS (meaning they are inert to each other and have to be ignited with oxygen present to react... Wink

).

icecool · Insistent Chemist

I read this on megalomania...

Because nitromethane is useful as an explosive ingredient, its availability has dried up on the OTC market. One of its biggest uses is as automotive fuel for drag racers, they burn 100% anhydrous fuel instead of gasoline, but at $25 a gallon or more it's gonna cost ya. This is the same stuff used in the bomb at Oklahoma City, and McVeigh tipped off the feds asking for it at a drag race. It is also available as a component in fuel for model cars and airplanes at hobby shops, from which it can be distilled. Those fuels can be very expensive, however. Hobby shops usually sell it as high as 70% with other contaminants in it; they are also wise to someone asking for "the highest concentration of nitromethane" you should know exactly what kind of car you need the fuel for if you ask. To avoid the hassles of buying this forbidden fuel, I suggest making it yourself.
Synthesis: Prepare a mixture of 500 g of chloroacetic acid and 500 g of crushed ice in a large beaker. Add to this enough cold 40% sodium hydroxide solution to neutralize the acid and make the pH of the solution slightly alkaline, about 360 mL should suffice. Do not allow the temperature to rise above 20 °C while adding the hydroxide, failing to do so will cause unwanted sodium glycolate to form. Prepare a solution of 365 g of sodium nitrite in 500 mL of water. Add this solution to the previous solution in a round bottom 3-L Florence flask.
Set the flask up for simple distillation with the thermometer dipping into the liquid (yes, in the liquid, not at the condenser opening like it usually is). Keep the receiving flask cold with an ice water bath. Gently heat the solution until bubbles of carbon dioxide are evolved, this should happen at around 80 °C. Remove the heat as the reaction should proceed spontaneously, it should rise to around 100 °C while the nitromethane/water azeotrope distills over at 90 °C. If the temperature does not rise on its own, gently heat the flask to 85°C until it does. At this temperature the exothermic decomposition of the reactants becomes so rapid that continued application of heat might cause violent frothing, with significant loss of nitromethane. After the reaction subsides to 95-100°C, cautiously heat the flask to 110 °C, stop when no more nitromethane distills over.
This should make about 130 mL of nitromethane with 370 mL of water, they should form separate layers. Place the layers into a separatory funnel and allow them to stand for 30 minutes, afterwards drain off the lower layer of nitromethane. The water layer is mixed with one fourth its weight of salt and distilled to give another 10-12 mL of nitromethane. Add this to the nitromethane already distilled. The crude nitromethane is dried over anhydrous calcium chloride in a desiccator and redistilled to give 115-125 mL of pure nitromethane.
Yield is about 38%. The yield can be improved slightly by using 625 g of chloroacetic acid and 450 mL of 40% sodium hydroxide solution. Another increase in yield can be achieved by adding 374 g of boric acid after adding the sodium nitrite solution, but before doing any heating. You can use a smaller flask and do several distillations if you do not have a 3-L flask, just remember to never fill it more than two-thirds of the way.

Nicodem · Mon Apr 25, 2005 5:23 pm

MeOH and HNO₂ easily form the ester (Me-O-NO). This has nothing at all to do with reactions of bases with acids. MeOH is a nucleophyle which reacts with NO⁺ electrophyle formed in acidic conditions from HNO2. Like already told so many times - it is an esterification.

The reaction of alpha-halo-acids with NaNO₂ is a well documented method and much disscussed already. You can also make nitroethane, but making the required alpha-halo-propionic acid is not easy. There is a paper on this method in Rhodium files as far as I remember.

The only OTC method that still did not receive enough attention is the oxidation of oximes into nitroalkanes. In theory acetaldehyde oxime can be oxidazed to nitroethane with sodium perborate in acetic acid. I would rather use pyruvic acid oxime though as it has more possibility of success since there are less chances of side reactions taking over. Besides pyruvic acid can be bought more or less OTC. See the disscussion in the SciMad thread:
http://www.sciencemadness.org/talk/viewthread.php?tid=909