Been thinking that a mixture of 10ml methanol 5grams NaOH 5 liters of ethanol and 20 liters of water, bubbling carbon monoxide through the mixture at
35 degrees with the vapors going through quicklime should purify the ethanol close to 95%-99%.
The methanol, NaOH should make alittle sodium methoxide , that as the catalyst with methanol and cabon monoxide should make formic acid reacting with
ethanol and the ethyl fromate should evaporate through the quicklime make calcium formate and ethanol.
Thoughts? Metacelsus - 18-11-2013 at 18:29
No. Sodium methoxide does not exist in the presence of water. Your first step should be to distill the solution to get rid of the sodium hydroxide and
most of the methanol and water. You can get it up to 95.6% ethanol just by distillation. If you add a dehydrating agent you can go even higher.andy - 18-11-2013 at 19:22
I thought distilling you can only reach 85% typo?
I think this setup might work, and be easier than three or four distills....
Three 44gallon drums, the first drum has a pipe going down to the bottom were carbon monoxide is pumped in, and mixed with methanol(21 liters) and
sodium hydroxide(100gram), at the top a pipe goes from there into the second tank filled with 20% ethanol, 20litres of water and 5 liters of ethanol,
the vapors from the first tank(methyl formate 35bp) mix with water to make formic acid which reacts with the ethanol to make methanol/ethanol formate
and water, the temperature of the second drum is 60 degrees which goes into the third drum which has sodium methoxide/methanol(0.5litres) and changes
to ethanol/methanol and carbon monoxide.
[Edited on 19-11-2013 by andy]Ascaridole - 19-11-2013 at 03:03
What are you trying to remove from the ethanol? If its just water very careful fractional distillation will get you to 95.5% purity and that can be
brought to 99% purity by drying with CaO or molecular sieves.
The formate method sounds a bit odd. Did you have any literature to reference?
The methyl formate formation requires anhydrous conditions so your methanol would have to be anhydrous and sodium metal used as the sodium hydroxide
would produce a mole of water if the methoxide did form. Also your carbon monoxide feed gas would need to be dry.
Second your methyl formate reacting with water to form formic acid and methanol would probably not occur without a base present as saponification of
esters don't happen to any appreciable rate without a strong nucleophile
Third formation of your ethyl/methyl formate is a simple ester synthesis. This requires an acid catalyst, reflux, and if you want it to occur at any
appreciable rate azeotropic removal of water as it forms to drive your reaction forward.
Last your third drum would saponify your methyl/ethyl formate but you would be left with sodium formate and your alcohols, not carbon monoxide gas.
Perhaps you are on to something but there are a few holes in your procedure that need to be overcome. Till then distillation and use of drying agents
appear to be a more practical method.
andy - 19-11-2013 at 09:59
The last drum "A Text-Book of Practical Organic Chemistry" by Arthur Vogel, Published by Longman, 3rd edition" add the foumla on page 166-167 of
HCOOC2H6 = CO + C2H6OH with sodium ethoxide as the catalyst, just assumed methoxide could be used.
Didn't realize that NaOH in methanol would make water, you could probably add calcium oxide or calcium sulphate mole for mole to remove the water
made.
Quote:
Third formation of your ethyl/methyl formate is a simple ester synthesis. This requires an acid catalyst, reflux, and if you want it to occur at any
appreciable rate azeotropic removal of water as it forms to drive your reaction forward.
The last drum "A Text-Book of Practical Organic Chemistry" by Arthur Vogel, Published by Longman, 3rd edition" add the foumla on page 166-167 of
HCOOC2H6 = CO + C2H6OH with sodium ethoxide as the catalyst, just assumed methoxide could be used.
You can
just say 'Vogel', and anyone who's ever studied Organic Chemistry to any significant extent will know what you're speaking of. There's a <a
href="http://library.sciencemadness.org/library/books/vogel_practical_ochem_3.pdf#page=166">full PDF</a> <img src="../scipics/_pdf.png"
/> available in <a href="http://library.sciencemadness.org/library/index.html">the SM Library</a>.
My advice to you is to study a little bit more about the theory of Organic Chemistry before jumping into the practical techniques. While it's
tempting to go straight to experiment, without an understanding of the science behind what you're doing, you won't accomplish much.Ascaridole - 19-11-2013 at 12:50
No, HCl will not work, sulfuric and phosphoric acid are the go to choices.
The methoxide can be use as a substitute for the ethoxide however I think your missing the point, methoxide is a very strong base. Forming it isn't as
simple as using a drying agent with the NaOH. Sodium is used for a reason as the proton from the alcohol is reduced to hydrogen so the reaction is one
way favorite g products.
Sorry on my phone, so apologies for any mistakes in advanced.vmelkon - 20-11-2013 at 09:34
No, HCl will not work, sulfuric and phosphoric acid are the go to choices.
Isn't that going to make some diethyl ether?Ascaridole - 20-11-2013 at 14:13
No, ether will not form unless you heat it to 140°C and use a significant amount of acid. You could use p-TsOH for the Fischer rxn but classic under
grad rxn with simple alcohols and carboxylic acids use a few drops of sulfuric acid.andy - 20-11-2013 at 19:50
Thanks for the info, In the second drum, I have sodium oxide and ethanol, I add sulfuric acid as the catalyst.
Won't that make ether sulphate, sulfuric acid is stronger than formic acid?
[Edited on 21-11-2013 by andy]Ascaridole - 20-11-2013 at 20:31
I'm confused. when did I suggest adding an oxide then acid?
Sorry if I wasn't clear in my explanations. andy - 20-11-2013 at 21:24
The wiki article had me worried, all good.
Reading some more up, NaOH can be used to make sodium methoxide, and was thinking to remove water, you could freeze it, the methanol shouldn't freeze,
you might loose some SM out of solution, but if the water is removed....The first and third drum should be free of water to make formic acid and
breakdown etherfomate to ethanol.
