Org Prep Daily

September 6, 2006


Filed under: procedures — milkshake @ 12:05 am

Iodoxybenzoic acid (IBX)

o-Iodobenzoic acid 8.93g (36 mmol) was dissolved in 2M NaOH 20mL. KBrO3 12.02g (72 mmol) was dissolved in a cold mixture of sulfuric acid 20.4g (96%) and water 50mL in a large beaker. The KBrO3+sulfuric acid mix was heated in the beaker on a water bath to 75C. With stirring with a mechanical stirrer, a solution of iodobenzoic acid was carefuly added dropwise over 30 min-1 hour (using an addition funnel) so that foaming and thick sludge formation (of the iodosobenzoic acid intermediate) in the beaker was controled by the stirring while the temperature was maintained approximately around 75C so that bromine vapours evolution from the stirred reaction mixture was regular (and not exceedingly vigorous). After complete addition the mixture was stirred at 75C for additional 4h until the bromine evolution and foaming ceased and the reaction mix became nearly white and easy to stirr, with a heavy white microcrystalline precipitate. The reaction mixture was cooled on ice bath, the precipitated product (IBX) was collected by flitration, washed thoroughly with ice-cold water, then rinsed with a small volume of acetone and dried by air suction.

Y= 9.90g of a white microcrystalline heavy powder

This procedure was succesfully scaled up to 50g. (An efficient mechanical stirrer and a large beaker were necessary to fight the bubbly sludge.) A new procedure osing Oxone as a oxidant is reportedly superior to this bromate oxidation method. There is also an old procedure using chlorine gas as an oxidant.

IBX is explosive. High-purity batches have low sensitivity (comparable to TNT) but impure material contaminated with salts and the iodoso intermediate is reportedly far more sensitive. To reduce chance of a mishap, it is important to ensure a complete oxidation of the iodoso intermediate and to wash the product carefuly. This is easier managed in smaller-scale preparations.


  1. Try oxone. I found that to be an easier prep (sorry don’t have the ref handy)

    Comment by d-orbital — September 6, 2006 @ 3:45 pm

  2. Nice blog in here. If you need to prepare IBX go for the oxone preparation. It is very easy and much safer. The exploxiveness of IBX arises some times form trace amounts of bromine by-products.

    Comment by Hypervalent guy — September 14, 2006 @ 1:08 pm

  3. That oxone prep is from J.Org.Chem. 64(12) 4537.

    Comment by Curtis — October 3, 2006 @ 1:45 pm

  4. Thank you for the oxone reference.

    Comment by milkshake — October 3, 2006 @ 2:07 pm

  5. Thanks for the oxone is easy to handle.

    Comment by VASU — October 8, 2009 @ 10:26 am

  6. oxone using very easy to handle so use only oxone procedure. one more report
    Turk J Chem
    27 (2003) , 713 { 716.

    c TU¨BI_TAK

    Comment by manojkumar — October 26, 2010 @ 6:28 am

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