Provenance

Reference data from EU CLP Annex VI and published regulations — verify against your supplier's SDS before use.

Build a label

Substance profile

tert-Butyl hydroperoxide

tert-Butyl hydroperoxide is a liquid.

CAS 75-91-2 C4H10O2 90.12 g/mol Warning

01 · Identification

What tert-Butyl hydroperoxide is

tert-Butyl hydroperoxide is a liquid. Its molecular formula is C4H10O2 and its molecular weight is 90.12 g/mol. It boils at 89 °C, melts at -8 °C, is soluble in water.

Under the GHS it carries the signal word Warning. It is classed as flammable agents - 4th degree.

CAS number75-91-2
EC number200-915-7
Index number617-023-00-2
Molecular formulaC4H10O2
Molecular weight90.12 g/mol
Chemical class Flammable agents - 4th degree

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.

Signal wordWarning
Hazard statements assigned to tert-Butyl hydroperoxide
CodeHazard statement
H341 Suspected of causing genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.

Precautionary statements: P201, P280, P308, P313

03 · Physical and chemical properties

tert-Butyl hydroperoxide 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 89 °C (192.2 °F) decomposes, decomposes HSDB
88.89 °C (192 °F) decomposes, at 760 mmHg CAMEO
35 °C (95 °F) at 20 mmHg (reduced pressure) HSDB
Melting point -8 °C (17.6 °F) HSDB
6 °C (42.8 °F) HSDB
-7.78 °C (18 °F) CAMEO
Density 0.93 g/cm³ ICSC
0.896 g/cm³ at 20 °C HSDB
0.88 g/cm³ at 25 °C CAMEO
Solubility Soluble in water HSDB
Moderately soluble in water HSDB
Slightly soluble in water HSDB
Vapor pressure 23.0269 mmHg at 20 °C ICSC
3.07 mmHg at 20 °C DOE PAC
5.46 mmHg at 25 °C HSDB
Flash point 26.67 °C (80 °F) CAMEO
43 °C (109.4 °F) ICSC
26.67 °C (80 °F) below this value HSDB
Autoignition temperature 238 °C (460.4 °F) ICSC
Lower explosive limit (LEL) 5 % by volume ICSC
May explode on heating. From table HSDB
Moderately explosive; may explode during distillation. HSDB
Upper explosive limit (UEL) 10 % by volume ICSC
Vapor density 2.07 (air = 1) HSDB
3.1 (air = 1) ICSC
Odor threshold Odor Threshold Low: 0.05 [ppm] Haz-Map

Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.

04 · Handling and storage

Storing and handling tert-Butyl hydroperoxide

Storage conditions

Store in original container. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Recommended storage temperature 2 - 8 °C

Source: Hazardous Substances Data Bank (HSDB)

Incompatible materials

Violent reactions with traces of acids. Concentrated solutions may ignite spontaneously on contact with molecular sieve. Mixtures with transition metal salts may react vigorously and release oxygen.

Source: Hazardous Substances Data Bank (HSDB)

Reactivity

Most alkyl monohydroperoxides, such as TERT-BUTYL HYDROPEROXIDE, are liquid. The explosivity of the lower members (e.g., methyl hydroperoxide or possibly traces of the dialkyl peroxides) decreasing with increasing chain length and branching, [Bretherick 2nd ed. 1979 p. 10]. Though relatively stable explosions have been caused by distillation to dryness [Milas, JACS, 1946 68 205] or attempted distillation at atmospheric pressure (Castrantas 1965 p 15). Very soluble in organic solvents and alkali metal hydroxide solutions. Combustible and a moderate fire risk [Hawley].

Source: CAMEO Chemicals

Planning storage for a mix of chemicals? Check tert-Butyl hydroperoxide in the storage compatibility matrix →

Get the free GHS / CLP / OSHA deadline calendar

Verified 2026–2029 compliance dates in one PDF — plus alerts when the rules change.