Azo polymerization initiators

Synazo's supplies Azo initiators for many polymerisation reactions. Our initiator systems are used to initiate or terminate polymerisation processes, or to reduce content of residual monomer.

Synazo Azo Initiators are performance chemicals to best meet customer specific conditions such as reaction solvent, temperature profile, and monomers used. First order kinetics of temperature controlled generation of free radicals is a clear advantage over other initiator systems. In addition, no oxygen is released during reaction, preventing unwanted side effects of oxidation or oxygen-catalysed decay of products.

Product ranges

The principle chemical structure of an azo initiator is given below:

Proper selection/definition of side groups in the molecule allow for modifications of

  • solubility: either in aqueous or non-aqueous systems;
  • decomposition/half life vs. temperature;
  • further characteristics.
  • The most important characteristic of a polymerization initiator is the speed of formation of radicals. As a general measure, the terminus Half Life is used. The Half Life is defined as the time required for half of the molecules of a given quantity of initiator to decompose, and it is closely related to temperature as it follows kinetics under Arrhenius equation.

    Synazo's product range comprises a variety of water soluble Azo initiators as well as Azo initiators soluble in organic solvents.


    Most important initiators (per CAS No):

    Water soluble Azo initiators:

    [ 2997-92-4 ]      2,2'-Azobisamidinopropane 2HCl

    [ 27776-21-2 ]      2,2'-Azobis(N,N'-dimethylene isobutyramidine) 2HCl

    [ 2638-94-0 ]      4,4'-Azobis(4-cyanopentanoic acid)

    Azo initiators for organic solvents:

    [ 78-67-1 ]      2,2'-Azobisisobutyronitrile

    [ 13472-08-7 ]      2,2'-Azobis(2-methylbutyronitrile)

    Only basic Azo initiators listed. Please ask if your product is not listed here.

    Forms of supply

    Based on market's need, in combination with our objective to supply our products as safe as possible, our products are available in a variety of physical forms and packings.


    Standard form is crystalline. Granular form and pellets on request.


    Standard products come in 20 kg units packed in PE. For safe handling we recommend 5 kg units packed in water soluble bags (made of PVA).
    Additional packings and customer/application specific supply systems on request.

    Note on REACh

    All products are pre-registrated under REACh. Based on our background knowledge on the industry Synazo has volunteered to be SFF/Sief Formation Facilitator to many, if not all Azo Initiators used at commercial level.

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