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Author: Subject: Questions regarding Claisen condensation
Hexavalent
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[*] posted on 18-10-2012 at 09:43
Questions regarding Claisen condensation


Hello there, does anyone know

(a) if, during the workup, an organic acid is needed or can it be inorganic?

(b) if ethyl acetoacetate - the result of the condensation using EtOAc - can be distilled at standard pressure or will it decompose? Is vacuum distillation absolutely necessary for final purification?

Thanks

[Edited on 18-10-2012 by Hexavalent]




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[*] posted on 18-10-2012 at 10:31


Quote: Originally posted by Hexavalent  
(a) if, during the workup, an organic acid is needed or can it be inorganic?

(b) if ethyl acetoacetate - the result of the condensation using EtOAc - can be distilled at standard pressure or will it decompose? Is vacuum distillation absolutely necessary for final purification?


Any acid will do it, acetic, formic, hydrochloric, sulfric, phosphoric ect. The only thing that you must keep in mind, that choose an acid what is easily separate from the goal compound. If you make EtAcAc, then I would suggest to use a mineral acid and get rid from the excess acid by a wash with carbonate sol.

The vacuum distillation is just an option, the goal compound here is not sensitive to heat, so distill it on atm. pressure if you want, it won't get gunky. But the vacuum distillation is faster....




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Hexavalent
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[*] posted on 18-10-2012 at 10:52


Ok, thanks.

BTW, is there a way to distill without a thermometer? Lemme explain - my thermometer has a maximum temperature of 150*C, and this compound boils at 181*C. This gives an obvious problem...is there anything that can be done?

Should I wait and get a digital thermometer? If so, is this suitable?
http://www.ebay.co.uk/itm/DIGITAL-KITCHEN-PROBE-THERMOMETER-...

[Edited on 18-10-2012 by Hexavalent]




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