The Hive => Newbee Forum => Topic started by: xspikehead on July 31, 2003, 08:26:00 PM
Title: 99% Anhydrous IPA vs. EtOH
Post by: xspikehead on July 31, 2003, 08:26:00 PM
Hello all,
As the subject states, only more specifically, during a reductive alkylation (P2P, methylamine, activated aluminum), ethanol is called for during reflux. Is 99% Anhydrous IPA, the type available at the drug store, an acceptable substitite? Any help would be greatly appreciated, as SWIM has a VERY difficult time obtaining ethanol yet sees the IPA everywhere he goes. Thank you.
-xSpikeHead
Title: Yes, any lower alcohol goes.
Post by: Rhodium on August 01, 2003, 08:56:00 AM
Yes, any lower alcohol goes.
Title: Alcohol Uses
Post by: Aurelius on August 01, 2003, 02:22:00 PM
Post 203747 (missing)
(obituary: "Alcohol use in extraction", Newbee Forum)
(PS: Rhodium could you rate this post so it shows up the more selective searches)
Title: Alcohol substitution
Post by: Rhodium on August 01, 2003, 03:14:00 PM
Done. Also see
Post 405729 (https://www.thevespiary.org/talk/index.php?topic=8879.msg40572900#msg40572900)
(Rhodium: "Methanol instead of Ethanol", Methods Discourse)
Title: Rhodium: care to elaborate?
Post by: xspikehead on August 04, 2003, 10:35:00 PM
Rhodium, when you claim, "any lower alcohol goes", could you please elaborate as to how IPA is a "lower" alcohol than EtOH? That, and while I've read several threads here that state the type of alcohol used doesn't matter if used as a solvent, but may matter if used in a reaction, could anyone explain to me how to be sure IPA would work? Just that SWIM doesn't want to ruin any valuable precursors. Thank you.
Title: IPA is not a lower alcohol then EtOH
Post by: OcoteaCymbarum on August 05, 2003, 07:29:00 AM
And its not what he meant. Lower alcohols refers to the number of carbons per molecule. Of course the order would be: Methanol-Ethanol-Propanol(or iso)-Butanol and so forth
When ethanol is called for as a solvent like in your case, isopropanol can be interchanged(I guess there are exceptions, but rare for our purposes) without a problem because it doesnt participate in the reaction.
In the reductive amination of P2P, the solvent isnt involved, so both can be used.
Title: There's a misunderstanding...
Post by: xspikehead on August 05, 2003, 10:29:00 AM
If you read my first post, you'll realize that EtOH is called for IN a reductive alkylation. P2P, Methylamine, Alunminum Turnings and yes, Ethanol, are all put into a flask and refluxed. My question was concerning switching EtOH with 99% Anhydrous IPA. So, this alcohol IS used in the reaction and that's why I was somewhat weary when I received the responses I did, without an explanation.
Title: Reductive amination
Post by: Aurelius on August 05, 2003, 11:11:00 AM
Be careful how quick you are to assume things. That alcohol IS NOT involved in the reaction directly. It is the solvent, meaning any alcohol capable of performing the required solvating effect can be substituted (assuming it has low reactivity to the reaction conditions present).
Lower alcohols are generally any alcohol containing 4 carbons or less. In some instances even the penta series is included, but not usually. Usually a reference to 'lower alcohols' means that either methanol or ethanol was or is used.
And yes, you can switch out the alcohols. Yields may vary a little bit, but they should still be very acceptable.
Title: Thanks!
Post by: xspikehead on August 05, 2003, 11:24:00 AM
Thank you for your prompt response and explanation. As soon as SWIM is able to get his hands on some EtOH, he'll post his yields using both the different types of alcohols. Thank you again!