Methoxide ion is an anionic initiator for polymerization reactions which is generally used in the form of Sodium methoxide. Can anyone suggest methods where just the methoxide ion and not sodium methoxide can be detected by any analytical technique/spectroscopic technique and also quantified?
Methoxide in solution should be readily identified and quantified by proton NMR (for any solvent other than methanol). What solvent are you in?
Electrochemical techniques may also be useful (MeO- is easy to oxidise).
@Aaron Bloomfield, Unfortunately the solvent, I am using is Methanol.
methoxide ion easily undergoes esterification . so if possible carry out its reaction which may end up with fruity smell, indicates presence of methoxide ion formation.
I think that in the solution of sodium methoxide in methanol there is an equilibrium between sodium methoxide and free methoxide anion:
CH3ONa --->
Sodium methoxide acts as a base in anionic polymerisation. The extent of polymerisation will depend on the actual content of methoxide in commercial sample of NaOMe. Since commercial samples are invariably contaminated with Na2CO3 and NaOH , it is imperative to know the active content of OMe in NaOMe for near complete deprotonation. I suggest interaction with analytical chemist who will evaluate NaOMe for its net active content (Assay) by standard titration method given in any pharmacopea
Methoxy ion can easily be detected and quantified by IR spectroscopy giving two strong bands near 1250 cm-1 and 1040 cm-1 (Ref. spectroscopy by Pavia)
Can you trap Methoxide with reacting and alkyl halide to form a bulky ether and quantify that ether after work up. I do not know if that helps but since MeO is reactive I would take advantage of that and react it with something your are sure only it will react to it and no other residue. That should give you answer for quantification unless reacting it will create more complications on your system. Just a thought.
If sodium methoxide in water solution, there are Na+ and MeO- ions in solutions. Because the salts of sodium dissolve and dissociate in water. So, all of methoxide are ionic form. If you acid added to solution, methanol take place in solution. And you can use GC for determination of amount of methanol.
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