{| class="toccolours" border="1" style="float: right; clear: right; margin: 0 0 1em 1em; border-collapse: collapse;"
! | '{{{name|'
|-
| align="center" colspan="2" bgcolor="#ffffff" |
|-
|
Chemical name
|
|-
| Other names
| methanedicarboxylic acid
|-
|
Chemical formula
|
|-
|
pKa
| 2.83 (pK
1)
5.69 (pK
2)
|-
|
Molecular mass
| g/mol
|-
|
CAS number
| []
|-
|
Melting point
| °C ''decomp.''
|-
|
SMILES
|
|-
! | Properties
|-
|
Density and
phase
| ? g/cm
3, Solid
|-
|
Solubility in
water
| Completely Soluble
|-
|
Melting point
| 135-136°C (408-409 K)
|-
|
Boiling point
| Decomposes
|-
|
Acidity (p''K''
a1)
| 2.83
|-
|
Acidity (p''K''
a2)
| 5.69
|-
| |
|-
|}
'Malonic acid' (
IUPAC systematic name: 'propanedioic acid') is a
dicarboxylic acid with structure
CH2(
COOH)
2. The
ionised form of malonic acid, as well as its
esters and
salts, are known as 'malonates'. For example,
diethyl malonate is malonic acid's
ethyl ester. The name originates from
Latin ''malum'', meaning ''apple''.
Biochemistry
The
calcium salt of malonic acid occurs in high concentrations in
beetroot.
Organic synthesis
A classical preparation of malonic acid starts from
acetic acid [1]. This acid is chlorinated to chloroacetic acid.
Sodium carbonate generates the sodium
salt which is then reacted with
sodium cyanide to the cyano acetic acid salt in a
nucleophilic substitution. The
nitrile group can be
hydrolysed with
sodium hydroxide to sodium malonate and acidification affords malonic acid.
Organic reactions
In a well known reaction malonic acid
condenses with
urea to
barbituric acid. Malonic acid is frequently used as an
enolate in
Knoevenagel condensations or condensed with
acetone to form
Meldrum's acid.
External links
★ MSDS http://physchem.ox.ac.uk
[1]
★ MSDS http://avogadro.chem.iastate.edu
[2]
★ pH spectrum http://www.Theoprax-Research.com
Disodium Malonate
★ pH spectrum http://www.Theoprax-Research.com
Malonic acid copper complex
References
1. ''Malonic acid'' Nathan Weiner Organic Syntheses, Coll. Vol. 2, p.376; Vol. 18, p.50 Online article