18 Carbonyl Compounds
Candidates should be able to:
(a) write the general formula for carbonyl compounds: aliphatic and aromatic aldehydes and ketones;
(b) name aliphatic and aromatic aldehydes and ketones according to the IUPAC nomenclature;
(c) describe structural and optical isomerism in carbonyl compounds;
(d) state the physical properties of aliphatic and aromatic aldehydes and ketones;
(e) write the equations for the preparation of aldehydes and ketones;
(f) explain the reduction reactions of aldehydes and ketones to primary and secondary alcohols respectively through catalytic hydrogenation reaction and with LiA1H4;
(g) explain the use of 2,4-dinitrophenylhydrazine reagent as a simple test to detect the presence of >C=O groups;
(h) explain the mechanism of the nucleophilic addition reactions of hydrogen cyanide with aldehydes and ketones;
(i) explain the oxidation of aldehydes;
(j) differentiate between aldehyde and ketone based on the results of simple tests as exemplified by Fehling‟s solution and Tollens‟ reagent;
(k) explain the reactions of carbonyl compounds with the structure CH3C=O with alkaline aqueous solution of iodine to give triiodomethane (iodoform test);
(l) explain that natural compounds such as glucose, sucrose and other carbohydrates which have the >C=O group;
(m) explain the characteristics of glucose as a reducing sugar.
18 Carbonyl Compounds
Candidates should be able to:
(a) write the general formula for carbonyl compounds: aliphatic and aromatic aldehydes and ketones;
(b) name aliphatic and aromatic aldehydes and ketones according to the IUPAC nomenclature;
(c) describe structural and optical isomerism in carbonyl compounds;
(d) state the physical properties of aliphatic and aromatic aldehydes and ketones;
(e) write the equations for the preparation of aldehydes and ketones;
(f) explain the reduction reactions of aldehydes and ketones to primary and secondary alcohols respectively through catalytic hydrogenation reaction and with LiA1H4;
(g) explain the use of 2,4-dinitrophenylhydrazine reagent as a simple test to detect the presence of >C=O groups;
(h) explain the mechanism of the nucleophilic addition reactions of hydrogen cyanide with aldehydes and ketones;
(i) explain the oxidation of aldehydes;
(j) differentiate between aldehyde and ketone based on the results of simple tests as exemplified by Fehling‟s solution and Tollens‟ reagent;
(k) explain the reactions of carbonyl compounds with the structure CH3C=O with alkaline aqueous solution of iodine to give triiodomethane (iodoform test);
(l) explain that natural compounds such as glucose, sucrose and other carbohydrates which have the >C=O group;
(m) explain the characteristics of glucose as a reducing sugar.
In short, carbonyl compounds can be divided into two major groups
– Aldehydes & Ketones
– Carboxylic Acid & Its derivatives
Methods of preparation of aldehydes and ketones
By Dehydration of Alcohols
CH3CH(OH)CH3−→−−−−Cu/573KCH3COCH3
From Hydrocarbons
1. By ozonolysis of alkenes
2. By hydration of alkynes
(g) explain the use of 2,4-dinitrophenylhydrazine reagent as a simple test to detect the presence of >C=O groups;