Substance profile
Maleic Acid
Maleic Acid is monoclinic prisms from water with a faint acidulous odor.
01 · Identification
What Maleic Acid is
Maleic Acid is monoclinic prisms from water with a faint acidulous odor. It boils at 135 °C, melts at 133 °C.
Under the GHS it carries the signal word Warning.
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H302 | Harmful if swallowed. |
| H335 | May cause respiratory irritation. |
| H315 | Causes skin irritation. |
| H319 | Causes serious eye irritation. |
| H317 | May cause an allergic skin reaction. |
Precautionary statements: P261, P264, P270, P272, P280, P301, P302, P305, P312, P313, P330, P332, P333, P337, P338, P352
03 · Physical and chemical properties
Maleic Acid properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 135 °C (275 °F) | decomposes, at 760 mmHg | CAMEO |
| Melting point | 132.5 °C (270.5 °F) | Melting point / Melting Range | HSDB |
| 287 °C (548.6 °F) | HSDB | ||
| 131 °C (267.8 °F) | ICSC | ||
| Density | 1.59 g/cm³ | ICSC | |
| 1.59 g/cm³ | at 20 °C | HSDB | |
| Solubility | In water, 788 g/L at 25 °C, 3926 g/L at 97.5 °C | at 25 °C | HSDB |
| 79.000 lb/100 lb water at 77 °F | at 25 °C | HSDB | |
| In water, 441,000 mg/L at 25 °C | at 25 °C | HSDB | |
| Vapor pressure | 0.0000134 mmHg | at 25 °C | HSDB |
| 0.000036 mmHg | at 25 °C | ICSC | |
| 0.0000359 mmHg | at 25 °C | DOE PAC | |
| Flash point | 127 °C (260.6 °F) | ICSC | |
| Vapor density | 4 (air = 1) | HSDB | |
| Corrosivity | May corrode metals when wet. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Maleic Acid
Storage conditions
Keep container tightly closed in a dry and well-ventilated place. Keep in a dry place. Storage class (TRGS 510): Non Combustible Solids
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Oxidizing agents
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
MALEIC ACID is a colorless to white crystalline solid. Moderately toxic. When heated to decomposition it emits irritating fumes and acrid smoke [Lewis, 3rd ed., 1993, p. 790].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Maleic Acid in the storage compatibility matrix →