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Author Topic: The yield of ester  (Read 544 times)

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hibahansari

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The yield of ester
« on: October 12, 2017, 04:08:08 AM »

Hello,
I am working on an esterification practical for Year 12. I used 1-butanol and ethanoic acid to produce butyl ethanoate. I calculated my %yield and it turned out to be 40.4%. For my report, I have to address how I can modify the practical to improve the yield. I have already talked about using excess reactants to cause a shift in the equilibrium which produces a better yield and also about minimise transfers between glassware to avoid losing products but I haven't met the word count and I have literally searched the internet for more ideas but I can't think of anymore.
I would really appreciate if someone could help out with this, my report is already overdue, lol  ;D
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Babcock_Hall

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Re: The yield of ester
« Reply #1 on: October 12, 2017, 04:37:45 AM »

Think about Le Chatelier's principle some more.
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GinaTageldin

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Re: The yield of ester
« Reply #2 on: October 21, 2017, 05:03:46 PM »

you may try to use thionyl chloride which improve the yield up to 90% instead of using classical Fisher estrification.
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kriggy

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Re: The yield of ester
« Reply #3 on: October 22, 2017, 02:16:53 AM »

If you dont describe the procedure, we can give you only common advice how to describe your low yield. Im doing fisher esterifications and they work quite well, but it takes refluxing overnight to get hight yield. Maybe your reaction time was just not long enough

OrganicDan96

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Re: The yield of ester
« Reply #4 on: October 22, 2017, 11:03:48 AM »

you may try to use thionyl chloride which improve the yield up to 90% instead of using classical Fisher estrification.
the op says this is a practice for year 12, I would think Thionyl chloride would be too hazardous for this sort of practical.

How much H2SO4 is being used, adding more might help shift the equilibrium.
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wildfyr

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Re: The yield of ester
« Reply #5 on: October 22, 2017, 11:35:44 AM »

I think everyone but Babcock is missing the most important point here. Normally I would help OP along, but I think he is gone since his report is due, and maybe this will help people googling in the future.

. The answer to how to improve yield of a Fischer esterification is to find a way to remove water from the reaction. Whether that  be by azrotropic distillation with Dean Stark or the addition of a drying agent, this is the single most important factor to get Fischer to work.
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kriggy

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Re: The yield of ester
« Reply #6 on: October 22, 2017, 10:57:37 PM »

Using alcohol as a solvent works as well without any need to remove water. Of course that is possible only for some alcohols (MeOH, EtOH..)
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