Carbonyl full summary

Preparation:

1. Mild oxidation of alcohol: [Cu+air]

   1°→ aldehyde

   2°→ ketone

2. Mild reduction of acid: [Ni+BaSO4]

   CH3-COOH → CH3CHO + H2O

3. Distillation:

   Calcium format → H-CHO + CaCO3

4. Industrially: [20% H2SO4, 2% HgSO4, 60°C]

   Ethyne + H2O → CH2=CH-OH→CH3CHO

5. Ozonolysis:

   Depends on carbon number whether aldehyde or ketone or both will be produced

Reactivity:

Methanal>Aldehyde>Ketone

Why: Nucleophile attacks more in methanal so it’s more reactive

Identification:

2,4 DNPH (2,4 DINITROPHENYL HYDRAZINE)

Schiff base→ yellow orange

Both aldehyde and Ketone gives same reaction

Properties:

1. Neucleophilic addition reaction:

   • SPECIAL CASE: Grignard reagent (R-MgX)

   Formaldehyde→1° alcohol

   Aldehyde→ 2° Alcohol

   Ketone→ 3° alcohol

2. Oxidation:

   •severe Oxidation:

   [K2Cr2O7 + H2SO4]

   3 products: Acid, CO2, H2O

   •Mild oxidation:

   ●FEHLING TEST:

   [Cu(OH)2 + NaOH]

   Gives red ppt

   ●TOLLEN’S REAGENT:

   [Ag(NH3)2]OH → Alkaline Silver Nitrate Solution

   Gives Silver mirror like ppt

☆☆☆☆☆ fehling test and tollen’s reagent test is used to differentiate between aldshydd and ketone because ketone doesn't give any reaction with these.

☆☆☆☆☆ fehling test and tollen’s reagent test proves that aldehydes (and acid as well) are reducing agent.

3. Reduction:

   •severe Reduction (CLEMENSON’S REDUCTION):

   [Zn-Hg] → Zinc amalgam + HCl

   Produces alkane

   •Mild reduction:

   [LiAlH4]

   Aldehyde→ 1° alcohol

   Ketone→ 2° alcohol

4. Reaction with alkaline solution:

   •CANNIZZARO REACTION:

   No alpha hydrogen required

   Formaldehyde Gives this reaction

   A type of disproportionate reaction

   Acid produced

   •ALDOL CONDENSATION REACTION:

   At least one alpha hydrogen MUST required

   Formaldehyde doesn't give this reaction

☆☆☆☆☆ Formaldehyde and other aldehyde/ketone are differentiated by these cultures Formaldehyde doesn't give aldon condensation reaction as they don't have any alpha hydrogen.

5. Haloform reaction:

   Halogen + NaOH

   Must be present: CH3-C=O- (aceto, acetyle, ethanoyl, methyl carbonyl group)

   If methyl carbonyl group is produced from oxidation of a compound, that gives haloform reaction as well.

   CH3-CH2-OH gives this reaction (exception)

   Haloform Color→ yellow

   C2H5-CHO and HCHO will not give this reaction coz methyl carbonyl is not present.

6. Condensation reaction:

   Two compounds will merge

   Nylon 6:6 is produced

   A kind of elimination reaction