Organic Chem Identification Reactions

Organic Chem Identification Reactions 1. Alkanes a. No identification (Free radical Substitution is not)

2. Alkenes a. Addition of bromine liquid/ dissolved in CCl4  Decolourisation of reddish-brown bromine b. Total bond cleavage with acidified KMnO4; Reflux  Decolourisation of purple MnO4-

3. Benzene a. Halogenation with bromine liquid and anhydrous AlCl3, at room temperature  Decolourisation of reddish-brown bromine

4. Alkylbenzene a. Halogenation with bromine liquid and anhydrous AlCl3, at room temperature  Decolourisation of reddish-brown bromine

5. Alcohols a. Halogenation with PCl5, cold  White fumes of HCl produced b. Tri-iodomethane/ Iodoform test with alkaline I2(aq), heat  Yellow precipitate formed (For alcohol with CH3 substituent)

6. Phenol a. Halogenation with PCl5, cold  White fumes of HCl produced b. Neutral Iron(III) chloride solution at room temperature  Violet coloration c. Bromine water at room temperature o Decolourisation of reddish-brown bromine and white precipitate of 2,4,6-tribromophenol

7. Aldehydes a. Oxidation with Acidified K2Cr2O7, heat  Orange solution of Cr2O72- turns green b. Oxidation with Acidified KMnO4, heat  Decolourisation of purple MnO4c. Tollen’s Reagent, heat  Formation of silver mirror  For comparison with ketone d. Fehling’s solution  Formation of reddish-brown precipitate  For comparison with ketone e. 2,4-dinitrophenylhydrazine (Brady’s Reagent), room temperature  Formation of bright orange precipitate  For comparison with non-carbonyl compounds f. Tri-iodomethane/ Iodoform test with alkaline I2(aq), heat  Yellow precipitate formed (For carbonyl compounds with CH3 substituent) Done by Nickolas Teo Jia Ming, CG 12/11

8. Ketone a. Oxidation with Acidified K2Cr2O7, heat  Orange solution of Cr2O72- turns green b. Oxidation with Acidified KMnO4, heat  Decolourisation of purple MnO4c. 2,4-dinitrophenylhydrazine (Brady’s Reagent), room temperature  Formation of bright orange precipitate  For comparison with non-carbonyl compounds d. Tri-iodomethane/ Iodoform test with alkaline I2(aq), heat  Yellow precipitate formed (For carbonyl compounds with CH3 substituent)

9. Benzaldehyde a. Oxidation with Acidified K2Cr2O7, heat  Orange solution of Cr2O72- turns green b. Oxidation with Acidified KMnO4, heat  Decolourisation of purple MnO4c. Tollen’s Reagent, heat  Formation of silver mirror d. Does not react with Fehling’s solution  For comparison with other aliphatic carbonyl compounds e. 2,4-dinitrophenylhydrazine (Brady’s Reagent), room temperature  Formation of bright orange precipitate  For comparison with non-carbonyl compounds

10. Phenylethanone a. Oxidation with Acidified K2Cr2O7, heat  Orange solution of Cr2O72- turns green b. 2,4-dinitrophenylhydrazine (Brady’s Reagent), room temperature  Formation of bright orange precipitate  For comparison with non-carbonyl compounds c. Tri-iodomethane/ Iodoform test with alkaline I2(aq), heat  Yellow precipitate formed (already has CH3 substituent)

11. Carboxylic acid a. Halogenation with PCl5, cold  White fumes of HCl produced b. Reaction with metal carbonate at room temperature  Effervescence of a colourless odourless gas (CO2)

12. Acyl chloride a. No identification

13. Ester a. No identification

14. Amide a. Alkaline hydrolysis  NH3 gas evolved for unsubstituted amide  For comparison with amine Done by Nickolas Teo Jia Ming, CG 12/11

15. Amine a. No identification

16. Phenylamine a. Aqueous bromine at room temperature o Decolourisation of reddish-brown bromine and white precipitate of 2,4,6-tribromophenol b. Sodium chlorate(I) solution at room temperature  Violet colouration

17.Halogenoalkane a. Formation of ester with Silver(I) salt of carboxylic acid in alcohol; Reflux  White precipitate o If chloroalkane  Pale yellow precipitate o If bromoalkane  Yellow precipitate o If iodoalkane

Done by Nickolas Teo Jia Ming, CG 12/11