Malonic acid
| Names | |
|---|---|
| IUPAC name
Propanedioic acid
| |
| Preferred IUPAC name
Propanedioic acid | |
| Other names
Carboxyacetic acid
Dicarboxymethane Methanedicarboxylic acid | |
| Properties | |
| C3H4O4 CH2(COOH)2 | |
| Molar mass | 104.061 g/mol |
| Appearance | White crystalline solid |
| Odor | Odorless |
| Density | 1.619 g/cm3 |
| Melting point | 135–140 °C (275–284 °F; 408–413 K) (decomposes) |
| Boiling point | Decomposition |
| 76.3 g/100 ml (25 °C) | |
| Solubility | Reacts with bases, amines Soluble in alcohols |
| Vapor pressure | ~0 mmHg |
| Acidity (pKa) | pKa1 = 2.83 pKa2 = 5.69 |
| Thermochemistry | |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | 157 °C (314.6 °F; 430 K) |
| Lethal dose or concentration (LD, LC): | |
| LD50 (Median dose)
|
3250 mg/kg (rat, oral) |
| Related compounds | |
| Related compounds
|
Oxalic acid Succinic acid |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Malonic acid or propanedioic acid is a dicarboxylic acid with structure CH2(COOH)2.
Contents
Properties
Chemical
If malonic acid is mixed with phosphorus pentoxide and heated, carbon suboxide is formed.[1]
Reduction of malonic acid yields 1,3-propanediol, the other isomer of propylene glycol.
Malonic acid may also condensed be with acetone to form Meldrum's acid, a versatile intermediate in further transformations.
Malonic acid is a key component in the Briggs–Rauscher reaction or Belousov–Zhabotinsky reaction, the classic examples of oscillating chemical reactions.
Physical
Malonic acid is a crystalline solid, soluble in water.
Availability
Malonic acid can be bought from chemical suppliers.
Preparation
The most common route to malonic acid involves neutralizing chloroacetic acid with sodium carbonate, which yields sodium chloroacetate. Addition of sodium cyanide will form sodium cyanoacetate, via a nucleophilic substitution. The nitrile group is then hydrolyzed with aq. sodium hydroxide to sodium malonate, and acidification affords malonic acid.
- Cl-CH2COOH + Na2CO3 → Cl-CH2COONa + H2O + CO2
- Cl-CH2COONa + NaCN → CN-CH2COONa + NaCl
- CN-CH2COONa + 2 NaOH → CH2(COONa)2
- CH2(COONa)2 + 2 H+ → CH2(COOH)2 + 2 Na+
Projects
- Make malonate esters and salts
- Preparation of barbituric acid
- Make carbon suboxide
- Preparation of 1,3-propanediol
- Demonstration of oscillating chemical reactions
Handling
Safety
Malonic acid is irritant, and has low toxicity.
Storage
In closed plastic or glass bottles.
Disposal
No special disposal is required. Can be neutralized with a base and poured down the drain.
