[Jall]

Hello,

I'm actually working on a project about graphite oxide (GO) and need to characterize the functionalities that are bond on the carbone lattice (of graphene). The main groups are :

- Hydroxyl
- Epoxy
- Carbonyls
- Carboxyls

I'm trying to develop a colorimetric method of quantification of the hydroxyls by selective derivatization. The problem is that I don't find any reaction that can be made selectively on a tertiary alcohol without reacting with the acids/carbonyls or the water present in the suspension of GO.

Has anyone any idea of a reagant that  :

- Can be measured by UV/VIS
- Reacts only with -OH groups (tertiary)
- Can be used in the presence of water

Any suggestion is appreciated

Thank you for reading

[pgk]

A tertiary alcohol reacts rapidly, if it is shaken with concentrated hydrochloric acid at room temperature and forms a tertiary alkyl chloride. The so formed tertiary alkyl chloride, can further react with N,N-dialkyl aromatic diamine, without heating and leads to the corresponding quaternary ammonium salt, which can be measured by UV Spectroscopy.
R3C-OH  →  R3C-Cl  →  [R3CN(R2)Ar]+,Cl-
Please, note that quaternization of the N,N-dialkyl aromatic diamine, leads to auxochromy that helps the differentiation between the reagent and the derivative, by UV spectroscopy.
As an indicative reference: European Patent 0791575 (1997)

[Jall]

Thank you very much for this insight.

I'm gonna try to makes the reaction on the graphite oxide lattice then filtrate the solid and analyse the filtrate by UV/VIS to see the quantity of reagant (probably N,N-dimethylaniline) that hasn't reacted.

Thank you again for your response