Ways to determine the concentration of alkyl halides in organic solvents I have a volatile alkenyl bromide dissolved in hexanes. I have to use the halide in a Grignard reaction but separating it from hexanes is hard (the bromide is light sensitive and very volatile). I would like to use the solution of the halide in hexanes but I don't know how to determine its concentration. I tried taking an NMR of the solution but all the peaks interfere and I can't choose two characteristic peaks to take a ratio. Is there a titration technique or some other technique to determine its concentration?
You could form the Grignard and titrate it. The Grignard should be fairly straightforward to titrate (e.g. as described by Knochel). This also has the advantage of giving you precisely the concentration of your reactive specie. If you knew only the concentration of your alkenyl bromide, you would not know precisely the quantity of Grignard formed (as the reaction is not always perfect).