Organic Compounds with Functional Group Containing Oxygen Part – 2
→ Those organic compounds in which carbonyl group (>C = O) is present are called carbonyl compound. Carbonyl group which has double bond (>C = O) between oxygen and carbon is a important functional group of organic chemistry. In different functional groups > C = O group is attached with different atoms or groups.
Example : In aldehde carbonyl group is bonded with carbon and hydrogen whereas in ketone it is bonded with two carbon atom.
→ Those carbonyl compounds in which carbonyl group is bonded with oxygen and carbon is called carboxylic acids and their derivatives.
Example : Ester, Anhydride etc.
→ Those compounds in which carbon of the carbonyl group is bonded with nitrogen or halogen are called amide and acyl halide respectively. Different organic compounds and their formula, in which carbonyl group > C = O is present, are as follows:
Summary of the chapter and glossary
→ Carbonyl Compound : Those organic compound which have carbonyl group are called carbonyl compound.
→ Cyanohydrin : Aldehyde and ketone both reacts with HCN to forms cyanohydrin.
→ Acetals : Aldehyde in presence of dry HCl gas reacts with monohydric alcohols and forms acet-als. A intermediate is formed in the reaction which is formed as hemiacetal.
→ Ketals : Ketone reacts with ethelene glycol and form cyclic ketals.
Some important facts.
- Those compound in which >C = O group is present are called as carbonyl compounds.
- Primary alcohol on oxidation gives aldehyde whereas secondary alcohol on oxidation forms ketone.
- Cohen’s reagent is a mixture of chromium tri-oxide and pyridine.
- 40% aqueous solution of formaldehyde is called formalin.
- Lederer—Manasse Reaction.
→ The product obtain in above reaction is used in the preparation of bakelite and novalake.
→ Aldol Condensation : It is shown by aldehyde and ketone having α-hydrogen atom.
→ Cannizaro Reaction : It is shown by aldehyde which do not have α-hydrogen. Ketone do not show this reactions.
→ Reformastkey Reaction : In the presence of zinc and ether α-halogen ester and carbonyl compound forms β-hydroxy ester.
→ Claisen condensation:
→ Novengel Reaction : The condensation of compounds containing active methylene group occurs in this reaction.
→ Popoff s rule is used for reduction of ketones.
Parahydroxy alcohol obtained from reaction of methanal and phenol in presence of conc. H2SO4 condenses and form bakelite.
→ Carboxylic group have carbonyl (>C = O) and hydroxyl (—OH) group.
→ Carboxylic acid and alcohol in presence of acid forms ester and this process is called esterification.
RCOOH + R’OH → RCOOR’ + H2O
→ For strong acid the value of Ka is high and pKa is low whereas for weak acid the value of Ka is low and pKa is high.
Arad Eystart Synthesis
→ The carbonyl group (>C = O) attached with — OH group in carboxylic group does not give nucleophihc addition reaction and known as pseudo carbonyl group.