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copperastic
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[*] posted on 25-3-2014 at 13:09
ethyl acetate catalyst


Hi, I was wondering what I could use other than sulfuric to catalyze the reaction between ethanol and acetic acid. Thanks.



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[*] posted on 25-3-2014 at 13:13


Phosphoric would probably also work. You want something that isn't volatile, and doesn't have a nucleophilic conjugate base.



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copperastic
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[*] posted on 25-3-2014 at 13:15


Draconic acid do you mean phosphoric acid? Also could i use HCl? Because i know i need a strong acid.
Im gonna start making tons of esters once i get my distillation apparatus.




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[*] posted on 25-3-2014 at 13:20


As all esterification reactions, you'll be producing an equilibrium:
CH3CH2OH + CH3COOH → CH3COOCH2CH3 + H2O
You can shift the equilibrium to the right by removing one of the two reaction products (water or ethyl acetate). The boiling point of ethyl acetate and ethanol are neraly the same, so you can't simply distill the ester as it forms. That's why you should use sulfuric acid. It will absorb water (because it's a dehydrating agent) and thus shift the equilibrium to the right. Using other acids will only affect the speed of the reaction not the concentration of the end product.
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[*] posted on 25-3-2014 at 13:21


hydrochloric acid will not work very effectively as the HCl is a disssolved gas so when heating it will be lost from the reaction mixture also i think the Cl- ion is quite a strong nuecleophile your best bet is conc. phosphoric or sulphuric acid
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[*] posted on 25-3-2014 at 13:23


Quote: Originally posted by copperastic  
Draconic acid do you mean phosphoric acid? Also could i use HCl? Because i know i need a strong acid.
Im gonna start making tons of esters once i get my distillation apparatus.

Yes, I mean phosphoric acid, but hydrochloric acid is a poor choice- it's volatile (i.e., it will evaporate when you try to distill your product), and the chloride ion is nucleophilic, so you can get chloroalkanes instead of esters.




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Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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copperastic
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[*] posted on 25-3-2014 at 14:04


Where could i get some sulfuric acid for a cheap price?



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[*] posted on 25-3-2014 at 15:40


Maybe this can help you.



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[*] posted on 26-3-2014 at 01:32


I vaguely recall a mention of Boric acid being used as a 'green' alternative in this esterfication, I'm not on my laptop so I don't have the ref at the moment.
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[*] posted on 26-3-2014 at 06:55


Does anybody use the search engine at all?

https://www.sciencemadness.org/whisper/viewthread.php?tid=21...
https://www.sciencemadness.org/whisper/viewthread.php?tid=13...





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copperastic
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[*] posted on 29-3-2014 at 13:41


Draconic acid I just picked up 10 Oz. of 10 percent phosphoric acid solution could i use that for the catalyst? If its to dilute should i try distilling it with my make shift distiller (A distilling flask with side arm attached to vinyl tubing running through water then attached to a filter flask in a ice bath.



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[*] posted on 29-3-2014 at 15:09


https://www.sciencemadness.org/whisper/viewthread.php?tid=44...
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[*] posted on 30-3-2014 at 05:42


Quote: Originally posted by copperastic  
Draconic acid I just picked up 10 Oz. of 10 percent phosphoric acid solution could i use that for the catalyst? If its to dilute should i try distilling it with my make shift distiller (A distilling flask with side arm attached to vinyl tubing running through water then attached to a filter flask in a ice bath.


10 % is WAY TOO weak. Even 80 % wouldn't work that well, I think. You need to look up 'Fisher esterification' and understand the mechanism better. For the reaction to proceed you need to protonate the C=O group of the carboxylic acid, that takes a very strong proton donor, like concentrated sulphuric acid.




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copperastic
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[*] posted on 30-3-2014 at 06:48


blog fast could i concentrate it or should i to return it to the shop? I got calcium chloride at the same place so I could add HCl and later add the calcium chloride because it would dehydrate and HCl's a strong acid.



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[*] posted on 30-3-2014 at 06:51


Additionally, refluxing higher concentrations of phosphoric acid can etch your glassware pretty severely.

edit just checked the link and it says this is not as big of an issue as I thought. Maybe I am thinking of polymerizing it.

[Edited on 30-3-2014 by Chemosynthesis]
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[*] posted on 30-3-2014 at 07:14


but Chemo could i just boil a little of the water off without it etching?



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[*] posted on 30-3-2014 at 08:38


Quote: Originally posted by copperastic  
blog fast could i concentrate it or should i to return it to the shop? I got calcium chloride at the same place so I could add HCl and later add the calcium chloride because it would dehydrate and HCl's a strong acid.


To get to the concentration you need is hard. I'd keep the 10 % for other uses.

Can't you get any drain unblocker (about 95 % H2SO4 in some cases) where you are?

I'm not even convinced that 100 % H3PO4 would work...




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[*] posted on 30-3-2014 at 09:19


if you want bulk H2SO4 and dare to miscalculate how sudden SO3 can change your comfortability -- search around online for sulfuric acid for pool pH control, its usually 'tower acid' which is ~50%
this can be boiled down, at 70% it will start to release SO3, sure go ahead.. have an experience with perhaps the most nasty gas you will ever meet
it is around 98% when it reaches 300*C

before you decide to try this look up properties of sulfuric acid and SO3

otherwise usually 37% is available at stores where you buy car products, available in the form of 'battery acid'




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[*] posted on 30-3-2014 at 20:24


Do you have any sodium bisulfate? There are a fair number of references to using it as an esterification catalyst in the patent literature, and a couple research papers, though I can't get at those, sorry. It's a pretty strong acid. Obviously not as strong as straight sulfuric, but close to phosphoric and maybe easier to acquire?

EDIT: I linked the wrong patent. Somewhat relevant, but not at all the one I had intended. Corrected.

[Edited on 3-31-2014 by Etaoin Shrdlu]

[Edited on 4-1-2014 by Etaoin Shrdlu]
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[*] posted on 31-3-2014 at 00:08


Dilute acid is not only less effective as a catalyst; it can also be destructive to the yield of ethyl acetate due to the water that it introduces into the reaction. It is important to remember that the Fischer esterification is an equilibrium, meaning that the presence of water (one of the products) will shift the equilibrium back to the reactants side, thus decreasing yield. This is why concentrated sulfuric acid is the choice catalyst: it is both a very strong and very dehydrating acid. As a result, it catalyzes the reaction and shifts the equilibrium to the products side at the same time.



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copperastic
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[*] posted on 31-3-2014 at 03:32


Yeah i have 2 pounds of sodium bisulfate.



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[*] posted on 31-3-2014 at 04:07


Again I doubt if that will work but it's worth a shot, I suppose...

As the sodium bisulphate is likely to be insoluble in the reagent mixture, you've probably got a case of heterogeneous catalysis on your hands and that is likely to be much slower.

[Edited on 31-3-2014 by blogfast25]




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[*] posted on 31-3-2014 at 11:19


blog fast by slow do you mean like 1 year slow?



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[*] posted on 31-3-2014 at 12:53


Quote: Originally posted by copperastic  
blog fast by slow do you mean like 1 year slow?


Who knows?




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