Isopropyl alcohol to iodoform

triiodomethane (iodoform) reaction with alcohols THE TRIIODOMETHANE (IODOFORM) REACTION WITH ALCOHOLS This page looks at how the triiodomethane (iodoform) reaction can be used to identify the presence of a CH 3CH(OH) group in alcohols. Note: This reaction can also be used in testing for the CH 3CO group in aldehydes and ketones. You will find a link to this at the bottom of the page. Doing the triiodomethane (iodoform) reaction There are two apparently quite different mixtures of reagents that can be used to do this reaction. They are, in fact, chemically equivalent. Note: It would be silly to learn both of these methods. Use whichever one your examiners want - find out by looking at past papers and mark schemes. If you haven't got these, go to the Use the BACK button on your browser to return to this page. Using iodine and sodium hydroxide solution This is chemically the more obvious method. Iodine solution is added to a small amount of an alcohol, followed by just enough sodium hydroxide solution to remove the colour of the iodine. If nothing happens in the cold, it may be necessary to warm the mixture very gently. A positive result is the appearance of a very pale yellow precipitate of triiodomethane (previously known as iodoform) - CHI 3. Apart from its colour, this can be recognised by its faintly "medical" smell. It is used as an antiseptic on the sort of sticky plasters you put on minor cuts, for example. Using potassium iodide and sodium chlorate(I) solutions Sodiu...