A type
of organic compound with the general formula
RCOOH. Many carboxylic acids
occur naturally in plants and (in the form
of esters) in fats and oils, hence the alternative
name fatty acids. Carboxylic acids
with one COOH group are called monobasic,
those with two, dibasic, and those with three, tribasic. The methods of preparation
are:
1. Oxidation of a primary alcohol or an
aldehyde:
RCH2OH + 2[O] → RCOOH + H2O
2. Hydrolysis of a nitrile using dilute hydrochloric
acid:
RCN + HCl + 2H2O → RCOOH +
NH4Cl
The acidic properties of carboxylic
acids are due to the carbonyl group, which
attracts electrons from the C-O and O-H
bonds. The carboxylate ion formed,
R-COO–, is also stabilized by delocalization
of electrons over the O-C-O grouping.
Other reactions of carboxylic acids include
the formation of esters and the reaction
with phosphorus(V) chloride to form
acyl halides.
反応性
Silane Reduction of Carboxylic Acids is as follows: Ethyldimethylsilane and a ruthenium catalyst were used to reduce aliphatic carboxylic acids to the corresponding alcohol. With tris(pentaflfl uorophenyl)borane as catalyst, triethylsilane reduces carboxylic acids to the alkane.
