Organic chemistry ii lab#6

Jawza A. Al mutairi Teaching Assistant Princess Norah Bint Abdulrahman University Collage of pharmacy Pharmaceutical Chemistry Department Lab#6 Amines

Introduction: Amines are derivatives of ammonia in which one or more of the hydrogen's has been replaced by an alkyl or aryl group.

Nomenclature: Amines are described as primary (1 o ), secondary (2 o ), tertiary (3 o ) or quaternary (4 o ) depending on how many alkyl substituents are attached to the N atom

Nomenclature: Aniline N-methyl anilineN,N-dimethyl aniline

Physical properties

Physical prosperities  Color: all amines are colorless, but when expose to light the color well change.  Odor: characteristic.  Flammability: flammable with dark black smock.  Solubility: immiscible in water, but micible in HCL.  Effect in L.P: blue ( most of amines are base).

Chemical test

Generalized test: FeCl3 test: Procedure: dissolve 1ml of amine in 3ml of dil.HCL, then add 1ml of FeCl3. Aniline: green color. N-methyl amine: green color. N,N-methyl amine: green color.

N-methyl anilineAnilineN,N-dimethyl aniline

Chemical test Specific test for aniline: Nitrous acid reaction: Procedure: 1)In test tube “1”, add 3 drops of aniline and dissolve it with 2ml of dil.HCL, shack well. 2)Cool the test tube in iced water. 3)In test tube “2”, dissolve 0.5gm of NaNO2 in 5ml distal water.

Chemical test 4) add test tube “2” in test tube “1”, while shaking gently. P.S: if any ppt. formed, that mean the amount dil.HCL that been added is not enough to dissolve the aniline.

Chemical test 5) in beaker mix 1ml of phenol with 2ml of 30%NaOH, and add it to test tube “1”. Result: crimson color [known as Azo pigment]

Aniline

Chemical test Specific test for aniline: Krbel amine test: Procedure: add few drops of cloroform to the amine, then add 2ml of NaOH or KOH. Heat on water bath. Result: Krbel amine odor.

Chemical test Specific test for 2 nd and 3ry amine: Nitrous acid reaction: Procedure: 1)In test tube “1”, add 3 drops of aniline and dissolve it with 2ml of dil.HCL, shack well. 2)Cool the test tube in iced water. 3)In test tube “2”, dissolve 0.5gm of NaNO2 in 5ml distal water.

Chemical test 4) add test tube “2” in test tube “1”, while shaking gently. Result:  N-methyl aniline: oily yellowish.  N,N-dimethyl aniline: red.

N-methyl anilineN,N-dimethyl aniline

Chemical test  For the N,N-dimethyl aniline, add few drops of 10% NaOH, and leave it for 5 min. Result: formation of green ppt.

N,N-dimethyl aniline

Chemical test Specific test for 3ry amine: Methylene Orange test: Procedure: 1)In test tube “1”, add few mg of HSo3 in 1ml Na2CO3. 2)In test tube “2”, dissolve 0.5 mg of NaNO2 in 5ml distal water.

Chemical test 3 ) add 2-3ml of test tube “2” in test tube “1”, while cooling it in iced water, the add few ml of dil.HCL 4) in test tube “3”, dissolve 2-3 drops of amine in 2 ml dil.HCL 5) add test tube “3” to test tube “1”. Result: yellow color.

Chemical test Specific test for 3ry amine: Picric test: Procedure: 1)Dessolve 0.5ml of amine in acetone. 2)Add 2ml of Picric acetone solution, with shaking. Result: formation of yellow ppt.