2,6-Dichloroquinone 4-chlorimide reagent

Sulfur-containing samples show colored spots when sprayed with 2,6-dibromo-quinone-4-chlorimide Gibbs reagent). For preparation, 2 g of this compound is dissolved in 100 ml of acetic acid or ethanol. Heating to 110°C is necessary to give a reaction. This reagent also creates colored zones when samples contain phenols. For reactions with phenols, only the less-reactive 2,6-dichloroquinone-4-chlorimide can be used under the same conditions. 

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