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Topic: ACETYLATION  (Read 8306 times)

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Offline makfc

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ACETYLATION
« on: March 11, 2006, 08:56:26 AM »
I'm trying acetylation of m-HYDROXY BENZALDEHYDE to m-ACETOXY BENZALDEHYDE with acetic anhydride,  acetyl chloride and with other possible methods.

Can I get exact route of synthesis, reagents, experimental procedure for this reaction ?

Awaiting your replies....!!!




MAKFC
(nalini.patel@rediffmail.com)

« Last Edit: March 11, 2006, 10:29:51 AM by makfc »
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Offline movies

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Re:ACETYLATION
« Reply #1 on: March 11, 2006, 08:11:20 PM »
Generally, you just need an equivalent or two of some kind of base like pyridine or triethylamine.  The reaction could take as long as 24 hours, but there really isn't much to it.
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Offline makfc

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Re:ACETYLATION
« Reply #2 on: March 11, 2006, 10:42:53 PM »
In India, acetic anhydride is heavily banned by govt. & I wish to prefer acetyl chloride or some other reagent to perform this acetylation.

Do you have some more details for such options ?
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Offline HP

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Re:ACETYLATION
« Reply #3 on: March 12, 2006, 04:09:37 AM »
You may react your phenolic aldehyde first with NaOH to obtain the Na-salt and then  reaction it with acetylchloride. I think in concentrated water solution of Na-phenolats the reaction with AcCl will preferably be acetylation than hydrolize side reaction. After this you'll need extraction of acetylated product with some common solvent inmiscible with water..I am not sure if you may do acetylation with glacial acetic acid using azeotropic destilation with toluene at 85-90C and may be some salt catalyst...Carbodiimide activation acetic acid is another possible approach but i dont think its very proper rote for your reaction.
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Offline HP

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Re:ACETYLATION
« Reply #4 on: March 12, 2006, 04:30:43 AM »
I am sorry but the suggestion i gave you with glacial acetic acid is stupid i think and hardly to work(phenolic OH is some acid). Think about preesterification of isopropil acetate with your phenol
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Offline faust

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Re:ACETYLATION
« Reply #5 on: March 13, 2006, 02:08:29 PM »
Try :
1.5 equivalent of AcCl
2.5 equivalent of Et3N
1 Equivalent of phenol

In dichloromethane.

Disolve the phenol than the triethylamine.

Add AcCl when your mixture is at 0°C, then leave it at room temperature for one night.

Just wash with NaHCO3 saturated then extract with dichloromethane
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Offline makfc

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Re:ACETYLATION
« Reply #6 on: March 20, 2006, 01:06:19 AM »
Thanks Faust !  ;D

I will try this procedure.




mak  8)
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Offline makfc

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Re:ACETYLATION
« Reply #7 on: March 20, 2006, 11:56:02 PM »
Dear Faust,

After adding AcCl, I just have to keep it without stirring or can I stirr for overnight ? Besides, by overnight you mean 16-18 hours ?  ???

Pls revert..


MAK  :o
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Offline maidou13

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Re:ACETYLATION
« Reply #8 on: April 07, 2006, 02:39:51 AM »
I can’t image that reaction would happen. Would you help me to explain the mechanism of this acetylation? Are there some successful work to buttress up this experiment? ??? ???
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Offline movies

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Re: ACETYLATION
« Reply #9 on: April 12, 2006, 02:31:02 PM »
What is the confusion about this reaction?  It is one of the most common ways to make esters.  I've done it successfully many times.
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Offline maidou13

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Re: ACETYLATION
« Reply #10 on: April 13, 2006, 04:19:26 AM »
I'm so sorry! I have make a big mistake about the reation! :-[ :-[
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