Aldehydes And Ketones Test - 30

Catalyst SnCl₂​/HCl is used in Stephen’s reaction. which helps in formation of nascent hydrogen on reacting with acid. The Stephen's reaction is used to prepare aldehydes from nitriles or cyanides. The reduction of nitriles with stannous chloride and hydrogen chloride in ethyl acetate solvent produces imine intermediate.

In this reaction, a CO group is converted to CH₂​ group. This can be achieved by Wolff-Kishner reduction which uses reagent NH₂​NH₂​, OH⁻ (hydrazine in alkaline medium).
Clemmensen reduction (Zn(Hg)/HCl) cannot be used as in presence of HCl, the alcohol may undergo dehydration.

Fehling's solution consists of CuSO₄​ solution mixed with alkaline solution of sodium potassium tartrate also called Rochelle salt.

Benzilic acid rearrangement

The structures of acetophenone and benzophenone are . When acetophenone containing is treated with l₂​ and Na_2​CO₃​ it forms yellow precipitate of CHI₃​ whereas benzophenone does not give this test. Acetophenons gives iodoform test due to presence of'-COCH3 group.

Uses for paraldehyde: medicinal use

Paraldehyde is used to treat certain convulsive disorders. It also has been used in the treatment ofalcoholism and in the treatment of nervous and mental conditions to calm or relax patients who are nervous or tense and to produce sleep.

It is an example of aldol condensation. Propanal on reaction with dilute sodium hydroxide forms CH₃​CH₂​CH(OH)CH(CH₃​)CHO (3-hydroxy-2-methylpentanal).

acetophenone being aromatic ketone does not form adduct with NaHCO₃ whereas acetone does