math
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Can I increase acetone pH by adding a base?
Hello,
I'd like to know if it's possible to increase acetone pH to 8-10 by adding either NaOH or Ca(OH)2.
Thank you
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weiming1998
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Quote: Originally posted by math  | Hello,
I'd like to know if it's possible to increase acetone pH to 8-10 by adding either NaOH or Ca(OH)2.
Thank you
|
Remember that bases (the stronger the base the faster it goes, especially solid bases dissolved in anhydrous acetone) catalyses the isomerisation of
acetone to an enol(ate) , which reacts with more acetone in an aldol condensation reaction to form a mess of reddish, rather slushy, gunk. But if you
work quickly, probably. Do you need anhydrous conditions or in aqueous solution? And what reaction are you trying?
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Nicodem
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| Quote: Originally posted by math | Hello,
I'd like to know if it's possible to increase acetone pH to 8-10 by adding either NaOH or Ca(OH)2.
Thank you
|
No, acetone does not self-dissociate in the same manner as water and related protic solvents, so the pH in acetone can not be defined in any
reasonable way. Just consider: how would you measure the pH in acetone? You can dilute a sample with water and measure its pH but this value has
nothing to do with anything resembling the "pH in acetone" - it only indicates the alkalinity of the solutes present in acetone, nothing more.
If you add a base to acetone, you only have a suspension or a solution of a base in acetone, nothing more. If the base is strong enough, the acetone
slowly self-condenses to give diacetone alcohol.
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math
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I was reading that some plant material extractions are more efficient at a pH of 8-9, so I thought that aqueous acetone would do.
Thank you
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hyfalcon
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Stick with the Ca(OH)2 if you're doing plant extractions. Good source of food grade Ca(OH)2 is pickling lime. A good non-polar food grade solvent is
d-limonene. Smells like oranges though.
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