TERM 1
Carboxylic acid nomenclature
DEFINITION 1
For open chain carboxylic acids, counting th e longest continuous carbon
chain that contains the carboxyl group (COO H) as the parent chain and
replacing the e ending of alkane with oic a cid. Because carboxyl group is
always at the end of the chain, it is conside red as C1 and the position of
the carboxyl group does not need to be sp ecified in the name. If there
are other functional groups presents in the molecule, the carboxyl group
outrank the other functional groups. The ot her functional group are
considered as substituents. When carboxy l group is attached to a ring,
the parent ring is named( the final e ending is retained) and the suffix
carboxylic acid is added.
TERM 2
Structure and bonding
DEFINITION 2
In the carboxyl group, C and O on the C=O bond are sp2
hybridized, while the O on OH part is sp3 hybridized.
Carboxyl group has three resonance forms, thus electrons
are delocalized on the COOH group. O atom on the C=O
bond is most electron rich (nucleophilic), while the H on the
OH part is most electron deficient (electrophilic).
TERM 3
Physical properties
DEFINITION 3
Carboxylic acids have higher boiling points than alcohols,
ketones and alkenes due to formation of two hydrogen bonds
between the hydroxyl group of each molecule and the
carbonyl oxygen of the other. Carboxylic acids can form
hydrogen bonds with H2O, thus they have similar solubility in
H2O as alcohols do.
TERM 4
Acidity of carboxylic acids
DEFINITION 4
Carboxylic acids are the most acidic c lass of compounds that
contain only C, H and O. Great acidity of carboxylic acids is
attributed to stabilization of carboxylat e ion (COO-)by inductive
effect of carbonyl group and resonan ce stabilization of carboxylate
ion. Electron-withdrawing sub stituent on the -carbon can help
stabilize the carboxylate ion via induc tive effect and thus increase
the acidity of the carboxylic acid. The acidity of the benzoic acids
with EWG at the ortho position is incre ased comparing to those
with EWG at the meta and para posit ions.
TERM 5
Salts of carboxylic acids
DEFINITION 5
Carboxylic acids can be deprotonated by strong base (NaOH or
KOH) to form carboxylate salts. For low molecular weight acids ,
sodium and potassium carboxylate sa lts are soluble in
water.Unbranched carboxylic acids w ith 12-18 carbons give
carboxylate salts that form micelles i n water, which is the
spherical aggregates with carboxylat e ions (the polar head) on the
outside and nonpolar tails (the R chai n ) on the inside.
