Diacetyl peroxide (CAS 110-22-5)

CAS Number

110-22-5

Molecular Formula

C4H6O4

Molecular Weight

118.09

EINECS Number

203-748-8

MDL Number

MFCD00008620

BRN Number

1753975

Last Updated

6/1/2026

Appearance

Colorless crystals or oily liquid (pure state), commercially only available as a phlegmatized solution

Appearance State

Solid or liquid depending on purity and formulation. Slightly soluble in cold water, miscible with most organic solvents like dimethyl phthalate.

Color

Colorless

Odor

Sharp, strongly pungent odor

Form

Crystalline Solid or Solution

Melting Point

30 °C (decomp)

Boiling Point

121.4 °C @ 760 mmHg (Theoretical estimated. Highly thermal and impact sensitive in practice, starts decomposing at 30 °C and prone to explosion, normal pressure boiling point has no safety guiding significance)

Flash Point

32.2 °C

Density

1.163 g/cm³

Vapor Density

4.07 (air=1)

Vapor Pressure

14.6 mmHg @ 25 °C

Refractive Index

1.398 (predicted)

LogP Value

-0.04 (predicted)

Merck Index

Not Specified

Solubility

Slightly soluble in cold water, soluble in ethanol, ether, and dimethyl phthalate

Water Solubility

Slightly soluble (Experimental value, but high thermal decomposition risk and prone to hydrolysis, aqueous solution preparation has no practical industrial safety value)

Solubility Detail

Slightly soluble in cold water. Due to extreme explosion hazards and decomposition upon melting (30°C), storing or transporting this substance in its pure form is strictly prohibited. It must be phlegmatized and maintained as a stabilized, safe-handling solution (typically <= 25% in dimethyl phthalate) for industrial radical initiation applications.

Storage Conditions

Must be handled according to strict temperature-controlled organic peroxide standards. Ambient storage/transport is forbidden; it must be forced refrigerated between -20°C and 0°C. With an extremely low SADT (ca. 35°C), thermal runaway can easily trigger at normal summer temperatures. Store in an isolated, high-standard explosion-proof hazardous warehouse equipped with emergency pressure relief and dedicated ventilation. Avoid moisture, light, friction, and mechanical shock. Keep strictly isolated from reducing agents, acids, bases, and metal powders.

InChI Key

ZQMIGQNCOMNODD-UHFFFAOYSA-N

Signal Word

Danger

Hazard Symbols

E, O, C

Risk Codes

R2, R3, R5, R8, R34

UN Number

UN 3115 (Organic peroxide liquid, Type D, temperature controlled) or UN 2084 (Depending on active oxygen content and phlegmatized state of specific formulation)

IARC Classification

Not Classified

WGK Germany

2

RTECS Number

Not Specified

Auto-ignition Temperature

ca. 35 °C (自加速分解温度 SADT)

TSCA Listed

Listed (Active)

Packing Group

II

Customs Code

2915900090

Occupational Exposure Band (OEB)

Not Specified

Occupational Exposure Limit (OEL)

Not Specified

Immediately Dangerous to Life or Health (IDLH)

Not Specified