V-501 is a non-halogen water-soluble azo initiator having a high decomposition temperature. It is soluble in hot water or methanol and has a 10 hour half-life decomposition temperature of 69° C.

Chemical Name

4,4'-Azobis(4-cyanovaleric acid)

CAS No.: 2638-94-0
Molecular weight: 280.28

Physical characteristics

Appearance White powder
Melting/freezing point 120-123° C
10 hour half-time decomposition temperature 69° C in water
Activation energy 132.8 KJ/mol K
Frequency factor (ln A) 36.66
Solubility Freely soluble in ethanol, ether and formamide
Soluble in methanol, hot water and alkali
Insoluble in water and toluene
Self-accelerating decomposition temperature (SADT) 60° C


Main Applications

  • Adhesives and microgel
  • PMMA, casted plate and resists


  • EINECS No.: 220-135-0
  • REACH: n/a


Store under 20°C. Store container in a well ventilated position. Store only in the original container. Do not seal container gastight.

Safety information


For specific information on the safe handling of the product, please refer to the material safety data sheet (MSDS) which is available on request.