PhenolResorcinolCatechol Structures Physical properties: State Color Odor Solid, crystalline. Solid, flaky. Solid, fine powder. White Buff gray Phenolic.

OH

PhenolPhenol ResorcinolResorcinol CatecholCatechol

Structures

Physical properties:Physical properties:

State

Color

Odor

OH OH

OH

OH

OH

Solid, crystalline.

Solid, flaky. Solid, fine powder.

White Buff gray

Phenolic odor Characteristic odor

Ignition test (Dry heat test):Ignition test (Dry heat test):

Inflammability

Change in appearance

Change in color flame

Change in odor

Residue

CommentComment

All soluble in H2O

Solubility:Solubility:

L.p.: No change

Comment Comment All the compounds are neutral

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

PhenolPhenol ResorcinolResorcinol CatecholCatechol

Preliminary test:Preliminary test:Soda lime

On cold:

On hot:

30% NaOH

On cold:

On hot:

FeCl3

On cold:

On hot:

Conc. H2SO4

On cold:

On hot:

Penolic odor No reaction

Not done Penolic odor

No reaction for all

No reaction for all

Very diluted phenols + 1– 3 drops FeCl3

violet – blue color Green color which rapidly darkens

Not done for all

No reaction for all

No reaction for all

General class group test for phenols: General class group test for phenols:

Azo – dye formation test ≡ Diazotization test

PhenolPhenol ResorcinolResorcinol CatecholCatechol

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

NoNo azo – dye form {Decomposition, dark purple color}

Because the presence of hydroxyl gp near to each other

PhenolPhenol ResorcinolResorcinol CatecholCatechol

Specific test:Specific test:

Phthalein test

Phenol + phthalic anhydride + 4 drops Conc. H2SO4 cool Dry test tubeDry 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