I am conducting following electrochemical experiment on Au wires in organic medium:
I suppose the anodic reaction goes through a benzaldehyde intermediate:
The cathodic reaction is hydrogen evolution, so we are dealing with a disproportionation reaction. I suppose the hydrogen evolution comes from the methanol, so methanolate is regenerated in situ.
To confirm that this conversion is indeed possible, we wanted to take a NMR sample of out reaction solution in acetone-d6. However, as we conducted the experiment, the reaction volume turned yellow and cloudy, even in our second run of the experiment. Now our fear is that due to the high applied voltage also the phenyl rest of the benzaldehyde or the benzoic acid methyl ester gets reduced.
Does anyone have an idea what kind of side reaction could be responsible for this kind of discoloration and the reasons behind it and how it could be prevented?