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Old March 11th, 2005, 02:18
RobJim RobJim is offline
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Default Re: Question:how does these two substances going?

Quote:
Originally Posted by skyie
I want to know:when i mixed the solution of resorcin and the solution of Ammonium Metavanadate under the temperation 80 degree centigrade. The colour goes from orange to green .How does they going? If i want to mix them ,but make them don't reaction.which substance should i add ?
Thanks a lot for the answers and this cool forum.
Resorcin is a phenol ring meta- substituted with two hydroxy groups (1,3 benzenediol). Ammonium metavanadate is an ionic compound made up of an ammonium ion and the metavanadate ion (NH4(+)VO3(-)). The metavanadate ion is a vanadium atom bonded to three oxygens via two double bonds and a single bond.

See http://chemfinder.cambridgesoft.com/ for the structures of these molecules.

The OH groups will encourage negative charge to exist on the ortho- and para positions. This means the VO3(-) ion will tend to attack at the meta- positions. It will probably perform an addition-elimination reaction at one of the substituted carbons, displacing the -OH group and replacing it with the -OVO2 group. That's my guess anyway.

Because the -OVO2 group will add a lot of pi- conjugation to the molecule, it makes sense that the color would change.

To be able to put both substances in the same container at reaction temperature, you'd need to modify one of them so that it would no longer react. I'm not sure how you would do that. Maybe putting them in a basic solution, deprotonating the OH groups and making them hard to displace?

That's a guess anyway.