05-13-03 01:01
No 432860
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 nitroethane is then re-distilled, collecting the fraction between 114-116°C. Yield 46% of theory.
1. Could the K2CO3 in this synthesis be replaced with NaHCO3?
2. What is the purpose of K2CO3 in this reaction?
3. Also the three solid powders are mixed without use of a liquid?
4. Also how would one calculate the yield (46%) in grams?
Preparation of Sodium Ethyl Sulfate
Method 1 [1]
To prepare the sodium salt of ethyl hydrogen sulfate, a mixture of alcohol and H2SO4 is boiled under reflux, cooled, and an excess of calcium carbonate is added. The ethyl hydrogen sulfate is converted into the soluble calcium ethyl sulfate, whilst the excess of H2SO4 is removed as insoluble calcium sulfate. The aqueous filtrate is then mixed with just sufficient sodium carbonate to give sodium ethyl sulfate, the insoluble calcium carbonate being now filtered off. The solution of sodium ethyl sulfate can be concentrated on the water-bath without appreciable hydrolysis, and the sulfate finally crystallized out.
5. Can Calcium Carbonate in this reaction be substituted with Calcium Oxide, molar ratios adjusted?
6. Also, can the Sodium Carbonate in this reaction be replaced with NaHCO3, molar ratios adjusted?
Thanks again,
Just need to confirm what can bee replaced with what...
(Newbee)
05-13-03 04:21
No 432890
ive never done this... so i can answer all of it.... i assume the carbonate is just use as a base... wont comment on switching as i havent really looked at the mechanism - so i really dont know
for working out your yeild in mass ... 46% yeild (or what ever it was) .. means you get 46% molar weight of what you should get... for every 1 mol or sodium nitrite you put in you should in theory get 1 mol of NO2et ...
n = m/M
n = 103.5g / 69g.mol-1
n (NaNO2) = X
so the expected mass of NO2C2H5 =
m = n.M
m = X.(14+32+24+5)
m (theoritical)= whatever that is... sorry i dont have a calculator on this puter :D
therefore 46 percent of the theoritical yeild will be 46 percent of m(theoritical). this is like 9th grade high school chemistry..
as for mixing the three powders... well you have to heat it to 120 odd degrees... not many solvents will do that... so im guessing that you do bring them together in the flask.. but then i havent done the reaction... intimately often means grind them together...but im not recomending you do that..
this seems like a pretty dangerous reaction... if i were you id make sure i new everything i could... and do it in a much smaller scale the first time. (noone bitch at me for preaching safety!!!!!)
(Hive Addict)
05-13-03 06:06
No 432899
Thankyou for the reply,
I appreciate the time you invested. Your replies will help you and others in the future.
I am aware of the math involved in calculating yields, Im unaware of the reaction, what is the purpose of the K2CO3 in the reaction.
Yes, I would probably perform the reaction on the small scale at first. This seems like a very fun reaction to perform even if it is dangerous
(Hive Addict)
05-14-03 05:53
No 433070
I just need the answer if sodium bicarbonate can be substituted in the original reaction with NaNO2 and sodium ethyl sulfate over potassium carbonate. Rhodium? Chromic? Anyone?
(Hive Bee)
05-14-03 12:10
No 433107
Hidden Cloud,
I know how you feel when those in the know don't seem to be interested in letting you know what they know.
So I'll have a go...
For Sodium Ethyl Sulfate:
1. The quantity of K2CO3 used is 6.25 mol% of the NaEtSO4. This suggests to me that it is a catalyst and substituting might reduce yields. Not sure about this though.
2. Sounds like there is indeed no liquids. In the absence of any real knowledge of how the reaction works I'd also guess that the reactants should be dry i.e. anhydrous K2CO3 should be used. Not sure about this either.
3. Bones missed a point. The limiting reactant is the NaEtSO4 (1 mole vs 1.5 mole NaNO2).
If the reaction is
Et-O-SO2-O-Na + NaNO2 __> Et-NO2 + Na-O-SO2-O-Na
(just guessing, chemistry is a synonym for voodoo in my dictionary)
, then 1 mol NaEtSO4 __> 1 mol Et-NO2 = 75.07 g
At 46% yield this is 0.46x75.07 = 34.5g
For Sodium Ethyl Sulfate:
1. I'm sure CaO can be substituted but I'd be careful cos I expect it would be a considerably more exothermic reaction.
(Are you sure you can't get CaCO3? It's just chalk. I'll swap my CaCO3 for your CaO any day.)
2. Using Na Bicarb. instead of Na Carb. should be fine I think.
Mountain Boy
(Hive Addict)
05-14-03 22:52
No 433182
You are correct the reaction (according to Merck) is:
EtOSO2OEt + NaNO2 -> EtOSO2ONa + EtNO2
Thankyou for the clarification and the helpful reply!! Swim only has Lab Grade CaO but not CaCO3, ironically...
I better not mess with the procedures, its kind of like using NaOH over KOH in the safrole isomerization....it just wont work. Thanks a bunch, ill let you guys know how the reaction went....