Bromination in GAA at -10C

[starlight]

Someone attempted the bromination procedure in the following article:

https://www.thevespiary.org/rhodium/Rhodium/pdf/shulgin.2-amino-1-phenylbutanes.pdf

(you can find it at the bottom of the second column on page 161 - {page 8 of the pdf})

They found that it was impossible to follow the procedure exactly because of course the solutions in GAA are completely solid at -10C.

Anybody have any idea why the authors were able to do this at -10C?

[Rhodium]

I think the correct interpretation is that the reaction flask is to be placed in a -10°C cooling bath (crushed ice/salt 3:1) when adding the bromine solution, so that the heat evolved by the reaction is absorbed quickly. You are of course right in that any GAA solution will be solid if its internal temperature drops to -10°C.

[starlight]

The experimenter concerned found that even placing the reaction flask in a -10C bath solidified the reaction flask. They also found cooling to be un-necessary and that perfoming the reaction at an ambient temp of around +10C was perfect.