Aldehdydes and ketones
Aldehydes & ketones C n H 2n O (+)C=O(-) polar react with acid and base
Nomenclature A] Aldehyde 1] Ald. up to 4 c by common name of the acids to which they related. 2] More than 4 by replacing e(from alkane) by –al. 3] C of ald. Always No. 1 (not appear in the name).
Nomenclature: 4] Substituted ald. By alphabet. If (OH > C=C or C C ) ClCH 2 CH 2 CH 2 CH 2 CHO CH 3 CH 2 CH=CHCHO CH 3 CHOHCHClCH 2 CHO 3-Chloro-4-hydroxy pentanal
5] Aromatic aldehyd derivatives of simplest aromatic (bezald.) B] Ketones 1) Simple by alkyl substituent and word ketone
2] complicated ketones by IUPAC by replacing (e) by(- one) (in longest cont. chain with C=O) ket. Take lower no. CH 3 CH 2 COCH 3 CH 3 COCH 2 CH 2 CH 2 CH3 CH 3 CH 2 COCH 2 CH 2 CH 3 CH 3 CH 2 CHClCOCH 2 CH 3 CH 3 CH 2 CH=CHCOCH 3 3-hexene-2-one Butanone 2-Hexanone 3-hexanone 4-chloro-3-hexanone
3] If position of C=O not clear no. is needed for no.
Physical Properties. -Simple (1-6) ald. & keto. Soli. in H 2 O - If R (inc) soli. (dec.) - more than 6 C insole. Dipole- dipol attractions Solubility B.P ald &ket. > alkane (same m.wt) Boiling point C=O polar, So Ald. & ket Polar (intermolecular attraction)
Preparation of Aldehydes & ketones 1] Oxidation of 1 & 2 alcohol : 2] Ozonolysis of alkenes:
Preparation of Aldehydes & ketones 3] Hydrolysis of alkynes: HC ≡ CH+ H 2 SO 4 aldhyde
4] Friedel Craft acylation:
Reactions of Aldehydes and ketones 1] Addition of metal hydrides( formation of alcohol)
Reactions of Aldehydes and ketones 1] Addition of metal hydrides( formation of alcohol)
2] Reactions with Grignard reagent:
3]Addition of alkynide ions: {R-C ≡ C(-)} 4]Addition of hydrogen cyanide (cyanohydrins formations):
H2OH2O CH 3 +
5] Addition of alcohols Ald.. + alcoh. — H+--- hemiacital Ket. + alcoh. — H+--- hemiketal a) Hemiacitals formation b) Hemiketals formation
c) Acetal formation: d) Ketal formation: OH
6] Addition of ammonia and it's derivatives
Reduction of oxime 7] Iodoform reaction O 0
8]Aldol condensation: Aldehydes Ketones +