Sciencemadness Discussion Board

Will heat accelerate a Sandmeyer Reaction?

ExothermicReaction - 3-12-2007 at 21:36

Just finished a very slow drip of ~500ml HCl into a flask which is now bubbling along as the reaction continues. I'm trying to streamline this synth and the 'wait 20 to 24 hours' part is a big sticking point. I know that I want to keep the reaction cool as I'm adding the HCl so as to retard the production of NO2, but what about one things settle down? Can this sort of reaction be sped up by heating the solution? Would it be possible to really speed things up by bringing it to reflux? Or is there something about this reaction that just takes time?

[Edited on 4-12-2007 by ExothermicReaction]

chemrox - 3-12-2007 at 23:51

It's believed to be a single electron transfer. The rate determining step is probably the reduction of the diazonium halide to the radical. After that minus N2 goes fast.

not_important - 4-12-2007 at 00:05

Remember that the diazonium salt isn't heat stable, and can take alternative paths to the one you want. One method of converting diazonium salts to phenols is to drip the salt into a boiling solution of dilute H2SO4, Na2SO4, and CuSO4.