Quantification of bromine (Br2)

[bmeekins]

I'm new to these forums, but I'm hoping I might be able to get some help with a problem I'm having. I'm working on a project that will (hopefully) produce a continuous stream of bromine via electrolysis of anhydrous hydrogen bromide gas. The actual process of doing the electrolysis is not overly difficult, but I'm trying to come up with a good way to quantify the amount of bromine that is produced so that we can determine the Faradaic efficiency of the reaction. In looking through the literature, it seems that I could try and do some kind of colorimetric measurement or bubble the product stream through an organic solvent, but in each case I'm concerned that the amount of bromine will be under-reported.

Any suggestions on how I might tackle this? Thanks!

[John Cuthber]

2 hours ago, bmeekins said:

I'm concerned that the amount of bromine will be under-reported.

Why?

In any event, you can check by titration.

2 hours ago, bmeekins said:

electrolysis of anhydrous hydrogen bromide gas.

HBr does not conduct.

[bmeekins]

1 minute ago, John Cuthber said:

Why?

In any event, you can check by titration.

 

Because, as stated, we want to determine the Faradaic efficiency of the reaction. Such a calculation requires precise determination of the number of mols of product so we can compare it accurately with the total charge passed. If the amount of Br2 measured is lower than the actual amount made, our apparent Faradaic efficiency will be less than the actual value.

[bmeekins]

9 hours ago, John Cuthber said:

HBr does not conduct.

This is correct, but it can be catalytically oxidized: https://www.sciencedirect.com/science/article/abs/pii/S0360319906002679

[John Cuthber]

12 hours ago, bmeekins said:

If the amount of Br2 measured is lower

Why would it be?

Are you assuming you can't get the right answer?

[chenbeier]

The topic should be moved to inorganic chemistry.