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Author: Subject: Concerning the synthesis of Ethyl Acetate
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[*] posted on 14-5-2011 at 19:48
Concerning the synthesis of Ethyl Acetate


im synthesizing Ethyl Acetate for a lab im using reagent grade ethanol and glacial acetic acid. CH3CH2OH + CH3COOH ⇌ CH3COOCH2CH3 + H2O is the reaction now we can shift equilibrim to the right by the removal of H2O. so i was thinking of using H2SO4 to dehydrate it and then due to the fact that ethyl acetate is very volatile, i could just distill it out from the mix. Would this work?
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[*] posted on 14-5-2011 at 20:12


or would the H2SO4 dehydrate the ethanol?
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hkparker
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[*] posted on 14-5-2011 at 20:41


H2SO4 would defiantly react with the ethanol. When you synthesize ether you begin by adding ethanol to conc. H2SO4, and you have to do so after both have been in a freezer for quite some time to prevent a reaction from proceeding too quickly. It wont completely dehydrate the ethanol, but protinate it. Not to mention ethyl acetate and sulfuric acid might make ethyl sulfate and acetic acid, though I'm not 100% sure of this.



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[*] posted on 14-5-2011 at 20:48


ahh i see, so how would you reccomend i proceed? i am currently looking at the tishchenko reaction for it, i am just teaching my self O Chem and im not particularly good at it but im trying to understand this
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[*] posted on 14-5-2011 at 20:54


I too and new to O chem so I don't have a whole lot of authority to speak. I came across <a href="http://www.sciencemadness.org/talk/viewthread.php?tid=13298" target="tab">this thread</a> that talked about the synth of ethyl acetate. It seems like H2SO4 is used there so I might have been totally wrong, my apologies. I didn't read it too in depth but sounds like youl need to refux and frac distill.



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[*] posted on 14-5-2011 at 20:56


yea man o chems a bitch but sooooo interesting, im just going to be starting my AP course soon, an o chem is not on curriculum so i have to teach myself it
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[*] posted on 14-5-2011 at 20:57


yea, I took AP last term and was disappointed with the lack of O-chem. though I can't see half the kids in that class being thrilled to learn about it so I can see why its not in there. Did you check out that thread?



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[*] posted on 14-5-2011 at 21:04


yea man reading as we speak and i kno most of the kids in my honors level class were crack heads. 1 kid was actually sniffing on acetone in the class. but yea man o chem is raw i start getting deep thoughts about why things happen the way they do and i end up confusing my self up like crazy
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[*] posted on 15-5-2011 at 06:34


Dump it all into water after the reaction is done, extract the ethyl acetate layer(top), wash with water, dry, redistill.
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[*] posted on 15-5-2011 at 07:46


Quote: Originally posted by #maverick#  
im synthesizing Ethyl Acetate for a lab im using reagent grade ethanol and glacial acetic acid. CH3CH2OH + CH3COOH ⇌ CH3COOCH2CH3 + H2O is the reaction now we can shift equilibrim to the right by the removal of H2O. so i was thinking of using H2SO4 to dehydrate it and then due to the fact that ethyl acetate is very volatile, i could just distill it out from the mix. Would this work?

Sigh. Every one wants answers, no one wants to read a book — do
the foot work.

This from the form library —

If you download only one book of practical organic chemistry,
make it this one. It is a classic of laboratory chemistry, well-
suited to the advanced home experimenter.


I could give you the page number, however .....
The WiZard is In helps only those who help themselves.
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[*] posted on 15-5-2011 at 07:50


You need to use H2SO4 as a catalyst or it will take forever for the equillibrium to set in. Look up the mechanism of a Fischer esterification.
You don't need much of it, I think 1mL is easily enough for say 25mL of ethanol used.
Just reflux you mixture of ethanol, acetic acid and H2SO4 catalyst for 1-2 hours, distill, was with sat. NaHCO3-solution and with sat CaCl2-solution (to remove EtOH), followed by water, dry over anhydrous CaCl2 and distill.
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entropy51
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[*] posted on 15-5-2011 at 08:28


A quick Google turns up this prep from Norris' Experimental Organic Chemistry which is also in the forum library:

Preparation of Ethyl Acetate from Alcohol and Acetic Acid (Section 128). - Mix in a dry 200 cc. distilling flask 50 grams of alcohol; 60 grams of glacial acetic acid, and 4 cc. of concentrated sulphuric acid. Cover the side-arm of the flask with a cork bored half way through its length. Connect the flask with a reflux condenser, and heat to boiling for 30 minutes. (See Fig. 14, page 25.) At the end of this time, arrange the apparatus for distillation, using a water condenser and having a thermometer to record the temperature of the vapor. Distil into a flask; when the temperature registers 100°, collect separately about 1 cc. of the distillate and add it to about 5 cc. of water. If the mixture does not separate into two layers, stop the distillation. Shake the distillate in the flask with 30 cc. of water, and add solid sodium carbonate until a drop of the ester is neutral to moist litmus paper. Transfer to a separatory funnel, draw off the water, and shake the ester twice with a saturated solution of calcium chloride, using 50 cc. each time. Draw off the ester into a distilling flask, add about one-fourth its volume of anhydrous calcium chloride, close the flask and cover the side-arm with corks, and let stand for at least 1 hour. Distil from a water-bath. Note the boiling-point and the weight of ester obtained, and calculate the percentage yield from the acetic acid used. Why from the acetic acid?

Ethyl acetate boils at 77°, has the specific gravity of 0.9028 18°/4°, and is soluble in 17 parts of water at 17.5°. The yield should be 80 to 85 per cent of the theoretical.

Note. - The sulphuric acid used in the preparation serves as a catalytic agent. The amount of alcohol used is that equivalent to the acid (equal molecular proportions) plus that which combines with the sulphuric acid to form ethyl hydrogen sulphate. The ester obtained in the first distillation contains alcohol and acetic acid. The former is removed by shaking with calcium chloride, and the latter by treatment with sodium carbonate.

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[*] posted on 15-5-2011 at 09:03


I would use sodium bicarbonate instead of carbonate. When you add a little too much you wont have to be afraid of the ester hydrolysing.
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[*] posted on 15-5-2011 at 15:33


esters are not so sensitive that a little excess base during workup will risk hydrolyzing them.



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[*] posted on 15-5-2011 at 18:48


Quote: Originally posted by The WiZard is In  
Quote: Originally posted by #maverick#  
im synthesizing Ethyl Acetate for a lab im using reagent grade ethanol and glacial acetic acid. CH3CH2OH + CH3COOH ⇌ CH3COOCH2CH3 + H2O is the reaction now we can shift equilibrim to the right by the removal of H2O. so i was thinking of using H2SO4 to dehydrate it and then due to the fact that ethyl acetate is very volatile, i could just distill it out from the mix. Would this work?

Sigh. Every one wants answers, no one wants to read a book — do
the foot work.

This from the form library —

If you download only one book of practical organic chemistry,
make it this one. It is a classic of laboratory chemistry, well-
suited to the advanced home experimenter.


I could give you the page number, however .....
The WiZard is In helps only those who help themselves.

im sorry mate im not trying to be ignorant here i actually tried searching in google and various other sites but i used the term synthesis of ethyl acetate and got almost nothing but now looking back i shouldve searched for the preparation of ethyl acetate which yielded better result.:)
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[*] posted on 15-5-2011 at 18:55


thank you very much entropy i am looking at book you posted at this moment
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