Aldehydes, Ketones and Carboxylic Acids

By oxidation of alcohol

Primary alkane oxidised in the presence of PCC to give aldehyde

Secondary alkane oxidised in the presence of CrO3 to give ketone

By dehydrogenation of alcohol

Primary alcohol gives aldehyde in the presence of Cu at 573K

Secondary alcohol gives ketone in the presence of Cu at 573K

Ozonolysis

Hydrolysis

Rosenmund reduction

Acyl halide reacts with hydrogen in the presence of Lindlar’s catalyst to give aldehyde and hydrogen halide

Stephen’s reduction

Nitriles react with hydrogen in the presence of SnCl2+HCl to give imine. Imine reacts with water to give aldehyde and ammonia

Etard Reaction

Toluene reacts with chromed chloride in the presence of CCl4/CS2/water to give benzaldehyde

Gattermann Koach Reaction

Benzene react with carbon monoxide and HCl in the presence of anhydrous AlCl3 or CuCl to give benzaldehyde

Preparation of Ketone from Acyl Halide

Acyl halides and R2Cd give ketones and Cadmium halide

Formation of hemiacetal and acetal

Aldehydes reacts with alcohol in the presence of dry HCl to give hemiacetal which on further reaction with alcohol gives acetal and water

Formation of Ketal

Ketones react with ethylene glycol in the presence of dry HCl to give ethylene glycol ketol

Clemmenson’s reduction

Aldehydes reacts with 4H in the presence of Zn-Hg amalgam and conc. HCl to give hydrocarbons and water

Wolff Kishner Reduction

Aldehydes or ketones reacts with hydrazine followed by heating with KOH and ethylene glycol to give hydrocarbons and ammonia

What is Tollen’s Reagent?

Freshly prepared ammoniacal silver nitrate solution

What is Fehling A?

Aqueous copper sulphate

What is Fehling B?

Sodium potassium tartrate or Roshcelle salt

Haloform Reaction

Aldehydes and ketones having attest one methyl group linked to the carbonyl atom are oxidised by NaOX to give haloform and Na salts of carboxylic acid

What is the condition for haloform reaction?

Carbonyl compound must have atleast one methyl group

What is the condition for Aldol condensation?

Aldehydes and ketones must have atleast one alpha hydrogen atom

What is the condition for cross aldol condensation?

It is carried out by 2 different aldehydes or ketones. If each of them has an alpha hydrogen then it gives 4 products

Cannizzaro reaction

Aldehydes undergo disproportionation reaction on heating with conc. alkali to form alcohol and Na salts of carboxylic acids

What is the condition for Cannizzaro reaction?

Aldehydes must not have an alpha hydrogen in order to undergo Cannizzaro reaction

What is formalin?

It is 40% formaldehyde solution.

What is Jones’ reagent?

CrO3 and sulphuric acid

Preparation of carboxylic acids by primary alcohol

Primary alcohol, in the presence of KMnO4 gives carboxylic acids

From alkyl benzene prepare c-acids

Toluene reacts with KMnO4 and KOH to give potassium salts of benzoic acids which on further reaction with hydronium ion gives benzoic acid

Prepare c-acids from Grignard reagent

Grignard reagent is hydrolysed with dry ice to give c-acids

Explain saphonification

Ester reacts with NaOH to give Na salts of c-acids and alcohols which on further reaction with HCl gives c-acids

Explain esterification

C-acids react with alcohols in the presence of concentrated sulphuric acid to give ester

What is Hell - Volhard - Zelinsky reaction?

R-CH2-COOH + X2 in the presence of red phosphorus gives R-CHX-COOH + HX