Kolbe-Schmitt car boration The last reaction shown above is a specific and unusual reaction of phenols, that is the direct reaction with Co, to give carboxylation at the ortho postion. This reaction is called the Kolbe-Schmitt carboxylation, and is important since the product is salicylic acid, which is widely used in pharmaceuticals. Another reaction which is highly specific for phenols is oxidation with Fremys salt: potassium nitrosodisulfonate to give the para-quinone as product. (KSOs)2NO Fremys salt: potassium nitrosodisulfonate Reactions Cleavage of Ethers with HI: Ethers undergo cleavage in the presence of aqueous hi to give the corresponding alkyl iodide. Attack will be at the least hindered carbon and El reactions, with carbocation intermediates, are common with ethers with groups which can form stable carbocations.The last reaction shown above is a specific and unusual reaction of phenols, that is the direct reaction with CO2 to give carboxylation at the ortho-postion. This reaction is called the Kolbe-Schmitt carboxylation, and is important since the product is salicylic acid, which is widely used in pharmaceuticals. Another reaction which is highly specific for phenols is oxidation with Fremy's salt: potassium nitrosodisulfonate, to give the para-quinone as product. Reactions Cleavage of Ethers with HI: Ethers undergo cleavage in the presence of aqueous HI to give the corresponding alkyl iodide. Attack will be at the least hindered carbon and E1 reactions, with carbocation intermediates, are common with ethers with groups which can form stable carbocations