Hi!
Swim was in dire need for a small amount of nitroethane for a new dream with some 2,5-meo substituted alpha-methylated compunds. The nitroethane synthesis was modeled after
Post 233762 (missing)
(Antoncho: "Kitchen nitroalkane success!", Chemistry Discourse). Anyway here goes:
100 mL 96% H2SO4 was placed in a RBF with a stirring magnet and placed in a cold waterbath. 130 mL of den. 93% ethanol(44% excess compared to methanol, because of greater molar weight) was dripped in while stirring. When the mixure got to hot, the addition was discontinued, till it had cooled down. After all the ethanol had been added, the mixure was reddish. The mixture was heated with a reflux condesor attached and after 30 minutes, ether started boiling of rapidly. At this point swim let it cool down and poured in some 60 grammes of Na2SO4 and continued heating for some time. Totally swim heated for 1 hrs.
After heating, the mixure was cooled and pulled through a lot of toilet paper(worked just fine) in a funnel, to give a reddish mixture.
120 g of Na2CO3 was slushed up in 350 mL 93% den. ethanol and poured in the cool mixture slowly, while stirring like a madman. After 30 mins the whole thing was added and CO2 evolution ceased.
This new mixure was strained through a cloth and the precipate was thrown in the oven and dried at 75 deg.
Yield: 110 grammes of ca. 60% NaEtSO4/NaSO4
So far so good...
After some days, 50 g og this powder was ground up really finely in a mortar and afterwards 50 g anhydr. sodium nitrite was ground aswell. This was ground up together in the mortar, till it resembled flour. This was placed in a 500 mL FBF and submerged in an oil bath. Swim set up for atm pres. distillation and started heating.
When the oil temp reached 150-160 degrees, the powder was still bone dry, but some reflux was seen. Shortly after, some liquid started coming over. The oil hit 190 degrees when this happened. After 40 minutes no more liquid came over and the reaction mixure was more "ugly", but not molten. Some discoloration was seen around the edges etc, but largely intact. The slightly yellowish liquid(looked a LOT like nitromethane), weighted 5.12 g. Swim was excited, as the reaction apparently had worked, but alas, swim made a huuuuuuuge mistage. He wanted to clean it a bit, so he mixed it with equal parts water and 1/2-2/3 dissolved, BUGGER! Swim looked up the soln. og nitroethane in water, and it was quite high...
After the wash about 2 g remained.
Swim has established success on this method, but there are some things that he need to improve:
1) Swim will let the ethanol / H2SO4 stand overnight with low heat applied to allow full conversion, and NOT make ether boil off.
2) Swim will not forget to add Na2CO3 to the final reaction mixure(although the Na2CO3 already present probably saved him from complete failure)
3) Swim will simply dry the crude nitroethane with CaCl2 and distill and skip the wash. To much was lost!!
All in all: A great synth, that requires few hard to get materials. Its a damn shame its so difficult to make such a small annoying molecule, that everyone should have lots of
now for my questions:
How pure does the nitroethane have to be, to work with the 2,5-DMBA condensation? Swim thinks its a lot easier to do the workup AFTER that reaction... How sensitive is that reaction to water?