PHENOLS

Phenol Resorcinol Catechol Structures Physical properties: State Color Odor Solid, crystalline. Solid, flaky. Solid, fine powder. White Buff gray Phenolic odor Characteristic odor

Ignition test (Dry heat test): Inflammability Change in appearance Change in color flame Change in odor Residue Comment All inflammable, luminous, smoky All melting All no change in color flame All on change in odor All no residue All the compounds are aromatic Solubility: All soluble in H2O L.p.: No change Comment All the compounds are neutral

Green color which rapidly darkens Phenol Resorcinol Catechol Preliminary test: Soda lime On cold: On hot: 30% NaOH FeCl3 Conc. H2SO4 Penolic odor No reaction Not done Penolic odor No reaction for all No reaction for all Very diluted phenols + 1– 3 drops FeCl3 Green color which rapidly darkens violet – blue color Not done for all No reaction for all No reaction for all

General class group test for phenols: Azo – dye formation test ≡ Diazotization test Phenol Resorcinol Catechol 1 drop aniline (red color) + dil.HCl (until dissolve) + NaNO2 (sod. Nitrite solution) until faint pale yellow color (1) {Diazonium salt formed} It is unstable because that we must put it in ice, without ice it will decompose few phenol + 10% NaOH (until phenol dissolved) (2) Add (1) on (2) gradually ((Azo – dye formation)) Orange – red color or ppt No azo – dye form {Decomposition, dark purple color} Because the presence of hydroxyl gp near to each other

Due to Alizarin indicator Phenol Resorcinol Catechol Specific test: Phthalein test Phenol + phthalic anhydride + 4 drops Conc. H2SO4 cool Dry test tube pour in beaker containing fussion 20 ml 10% NaOH Pink color Due to phenol phthaline ((indicator)) Green fluorescence H2O Fluorescence Blue color Due to Alizarin indicator