# Phenol and Deuterated Sulphuric Acid

What happens when phenol reacts with $\ce{D2SO4}$ in presence of $\ce{D2O}$?

How many hydrogens in total are replaced by deuterium?

Is the hydrogen of the hydroxyl group and three hydrogens ortho and para to the -OH group replaced by deuterium, and the remaining two unaffected?

OR are all hydrogens replaced by deuterium?

I'm not sure what really happens, but as far as I know - even though ortho and para positions are greatly activated, some small percentage of meta attack may also take place. In fact, if it does take place, the final compound will be totally deuterated, as bonds with deuterium are stronger than those with hydrogen, and backward reaction will not be thermodynamically favoured.

It'd be great if someone could explain what's going on, and if possible please quote sources supporting your answer. Thanks a lot.

• Check what Phenol-d6 costs. If you can buy it and it is not prohibitively expensive, that would answer your question I guess. – Karl Sep 12 '18 at 18:26