Re: COOH on carbon surface

From: charliew2 (charliew2_at_ev1.net)
Date: 06/26/04 

Date: Sat, 26 Jun 2004 13:25:13 -0500

Uncle Al,

I'm a bit curious. What is your background?

Uncle Al wrote:
> David Wang wrote:
>>
>> For some product we are developing, we need to create carboxylic
>> groups on some carbon electrode surface. Since I am not a chemist, I
>> was wondering if some can give me some suggestions on how to acheive
>> this. I prefer a wet chemistry (soaking and/or washing in certain
>> chemicals) approach rather than an electrochemical approach (applying
>> potential to the carbon electrode in certain electrolyte).
>
>
> The cheapest route that gets the job done is the winner. All the
> following functionalizations except for ozonolysis and nitrene/carbene
> additions are only effective at graphene edges. If you don't have
> edges at the surface (e.g., the surface is the basal plane of oriented
> graphite, Grafoil) you won't get functionalization.
>
> Depends what is on the surface to start. If you have graphene without
> alkyl substitution, you might try a big dose of gaseous ozone followed
> by dipping in a solution of periodic acid (or peridoic
> acid/permanganate couple) to cleave surface ring ozonides to acids.
> If there are alkyl or acyl groups on the surface, heating in Jones
> reagent (dichromate in sulfuric acid) or hot aqeuous acidic
> permanganate will do it.
>
> To get large carboxylate densities one imagines you should explicitly
> alkylate or acylate the surface (Friedel-Crafts with acetyl chloride)
> then chew on it with Jones or permanaganate. A more elegant approach
> would be to Friedel-Crafts acylate with succinic anhydride (anhydrous
> aluminum chloride, nitrobenzene, heat) to give you your pendant
> carboxyls on three-carbon spacers in one step (certainly after an
> aqueous base wash). If you want them snugged to the ring, Jones or
> permanganate thereafter to oxidatively cleave the chains.
>
> If you want those carboxyls on longer or more elegant spacers, use a
> suitable functionalized carbene or nitrene precursor and then
> photochemistry to covalently add to the surface rings.