ORGANIC CHEMISTRY || Pharmaceutical chemistry department Pharmacy college Princess Nora University

Phenols

objectives Write the functional groups of phenols differentiate between phenol and alcohols Determine chemical and physical properties of phenol Perform chemical and specific tests for phenols

Introduction class of chemical compounds consisting of a hydroxyl group (—OH) bonded directly to an aromatic hydrocarbon group Hydroxy benzene = phenol

What is the different between phenols and alcohols ? Alcohol has an -OH group bonded to a sp3 carbon phenols has an -OH group directly attached to a carbon of the aromatic ring (benzene). AR-OH

Properties phenols are polar due to the ability to form hydrogen bond phenols are water soluble Phenol can dissolve in NaoH Phenols are more acidic than alcohols but less acidic than Carboxylic acids.

Uses & toxicity Early uses for phenol was as an antiseptic. Phenol is used as a starting material to make plastics, explosives such as picric acid. Used in the production of aspirin and other pharmaceuticals. Detergents and emulsifiers, and also in insecticide and plastics production Phenols are hazard (handled with extreme caution). Phenol is highly corrosive to the skin . phenol will produce flammable vapors (highly toxic) .

Phenols Phenol Resorcinol Catechol

Physical properties Phenol Resorcinol Catechol State Solid ,crystalline Solid, flaky Solid, fine powered Color White Buff Gray Odor Phenolic odor or characteristic Flammability Flammable with luminous smoky flam Effect on L.P No change Solubility Soluble in water

Azo – dye formation test Chemical test General test FeCL3 Azo – dye formation test Specific test Phthalein test

General test FeCL3 test : Few mg of Phenols dissolve in water + 1-2 drop of FeCL3 colored triaryloxy complex Results: Phenol = violet color Resorcinol = violet color Catechol = Green color

General test FeCL3 test Results: Phenol Resorcinol Catechol violet color violet color Green color

GENERAL TEST Azo – dye formation test (( Diazotization test)) 1-2 dropof aniline (red color) + dil.HCl (until dissolve) + NaNO2 (sod. Nitrite solution) = until faint pale yellow color - PUT IN ICE Few phenol + 10% NaOH (until phenol dissolved) Add (1) on (2) gradually

GENERAL TEST Result : Phenol = ((Azo – dye formation))Orange – red color or ppt Resorcinol = ((Azo – dye formation))Orange – red color or ppt Catechol = No azo – dye form {Decomposition, dark purple color} -naphthol resorcinol phenol The dye is Benzene azo -naphthol Benzene azo resorcinol Benzene azo phenol

GENERAL TEST Azo – dye formation test (( Diazotization test)) Phenol Resorcinol Catechol No azo – dye form {Decomposition, dark purple color} ((Azo – dye formation))Orange – red color or ppt

SPESIFIC TEST Phthalein test : Few mg of Phenol + phatalic anhydride + 4 drops con.H2SO4 cool = then pour it in beaker contain 20 ml of 10%NaOH

SPESIFIC TEST Phenol = Pink color Resorcinol = Green fluorescence added water = fluorescence Catechol = Blue color

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