Pages: 1

Author Topic: Stability of catechols  (Read 81 times)

Stasis

  • Larvae
  • *
  • Posts: 2
Stability of catechols
« on: October 04, 2010, 12:29:08 AM »
OK, so I just stumbled across a paper that states that catechols are very stable when they form complexes with Fe(II) and Fe(III) ions, and auto-oxidation to quinones won't occur. Here's the reference for the paper:

hxxp://onlinelibrary.wiley.com/doi/10.1046/j.1462-2920.2001.00176.x/pdf

But yeah, as far as I see it, this has some serious implications for synthesis of some of our favorite catechol/dihydroxy compounds, and maybe some of our favorite methylenedioxy compounds...

"Catechols can form stable complexes with various di- and trivalent metal ions, the complexes with trivalent ions being the most stable."

"Fe(II) complexes form preferentially at acidic pH, whereas Fe(III) occurs at pH>7."

The rest of the paper is basically just discussion of catechol biological toxicity, which I couldn't care less about - I'm not planning on eating the stuff.

Does this mean it's as simple as chucking in a few grams of FeCl2 or FeCl3 and HEY, stable catechol??

I'll try and source the two other papers which were cited in this article, (Avdeef et al., 1978 and Hider et al., 1981)

zzhuchila_clocker

  • Subordinate Wasp
  • ***
  • Posts: 167
Re: Stability of catechols
« Reply #1 on: October 04, 2010, 01:17:58 PM »
catechol itself(o-hydroxyphenol) in solid state is known to be very stable (without light, moist, and air it can be stored for 10+ years). But in sol-n it oxidizes rather fast. What could be those implications? Methylenedioxy compounds would not form such complexes, protecting catechol from oxidation in reaction mixture would kill its reactivity. Probably, this can be used for extraction of phenolic and catecholic compounds that are prone to oxidation.

Who stuff the banks? Who staff the party ranks? More for Gore or the son of a drug lord?
None of the above, fuck it, cut the cord!
Lights out.. guerrilla radio
Turn that shit up

Stasis

  • Larvae
  • *
  • Posts: 2
Re: Stability of catechols
« Reply #2 on: October 05, 2010, 01:17:08 AM »
Maybe I'm overstating it a bit, but the implications could be that demethylation reactions which commonly cause polymerisation (= useless tar...) will still take place when Fe2+ is present, but the catechol which is formed in the reaction will be stabilised upon formation by the ions. It might even have a positive equilibrium effect. But I'm probably way off track.

letters

  • Subordinate Wasp
  • ***
  • Posts: 138
Re: Stability of catechols
« Reply #3 on: November 14, 2010, 05:51:16 PM »
like zzuchila_clocker said, solid crystalline catechol is stable. ours is stored in a white opaque bottle. the bottle is dated from 2007. it is still suitable for synthesis out of the bottle.
Pages: 1