Exercise 10: ALDEHYDES AND KETONES Flashcards
organic compounds both containing a carbonyl functional group
(C=O)
has two more bonds that may be occupied by hydrogen or alkyl or
aryl substituents
ALDEHYDES AND KETONES
if one R is hydrogen =
If both R are neither H =
aldehyde
ketone
naturally occurring
organic
compounds, often
combined with
other functional
groups
can be found in
plants, animals,
and even
microorganisms
ALDEHYDES AND KETONES
(cinnamon bark)
cinnamaldehyde
(musk deer)
muscone
(vanilla bean)
vanillin
(male sex hormone)
testosterone
(lemongrass)
citral
(female sex hormone)
progesterone
(a fungal toxin)
helminthosporal
(spearmint & caraway
carvone
(adrenal hormone)
cortisone
camphor tree)
camphor
largely responsible some of the shared physicochemical
properties of aldehydes and ketones
a - group because of the greater
electronegativity of the oxygen
as a result of this polarization, the carbonyl group is
susceptible to
CARBONYL GROUP
highly polarized
nucleophilic attack
commonly
synthesized in the
laboratory through
of alcohols
oxidation reaction
are oxidized to
aldehydes while
are oxidized to ketones
primary alcohols
secondary alcohols
TEST FOR CARBONYL GROUP
• 2,4-DNPH TEST
• SODIUM BISULFITE TEST
2,4-DNPH (BRADY’S) TEST results
acetone
clear orange solution
2,4-DNPH (BRADY’S) TEST results
acetophenone
yellow-orange precipitate
2,4-DNPH (BRADY’S) TEST results
acetone
Clear orange soln
2,4-DNPH (BRADY’S) TEST results
formaldehyde
reddish orange precipitate
detect the presence of carbonyl
group
2,4-DNPH (BRADY’S) TEST
reagent: Brady’s reagent
named after Oscar Brady
(2,4-
dinitrophenylhydrazine in methanol);
positive result: 2,4-DNPH (BRADY’S) TEST
yellow to orange precipitate for
aldehydes
red to orange precipitate for
ketones
condensation reaction; aldehyde
reacts with 2,4-DNPH to forms an while ketone reacts with
to form a
aldehyde 2,4-
dinitrophenylhydrazone
ketone 2,4-dinitrophenylhydrazone
SODIUM BISULFITE TEST results
acetaldehyde
white precipitate
SODIUM BISULFITE TEST results
acetone
white precipitate
used to determine if a compound is an aldehyde or
an aliphatic methyl ketone
SODIUM BISULFITE TEST
reagent: sodium bisulfite
SODIUM BISULFITE TEST
SODIUM BISULFITE TEST
positive result:
white precipitate
the reacts with
sodium bisulfite by breaking the pi bond of the carbonyl
group through - attack; the - then
attaches to the original carbonyl group to form the bisulfite
addition compound
aldehyde or the methyl ketone
nucleophilic
bisulfite ion
with ketones, only will yield positive result
(ketones with - groups sterically hinders the bisulfite ion
in attaching to the carbonyl group)
methyl ketones, bulky
SCHIFF’S TEST resuts
acetophenone
Clear colorless soln
SCHIFF’S TEST resuts
acetone
clear colorless solution
SCHIFF’S TEST resuts
acetophenone
clear colorless solution