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Physical & Chemical properties

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PHYSICAL & CHEMICAL PROPERTIES

 

·       appearance and physical state of 2,2’-Azobis (isobutyronitrile) is described as white needle-like crystals.

·       melting point of 2,2’-Azobis (isobutyronitrile) was found to be 100°C - 103°C (373 -376K); Source: Physicochemical property study report (1987 inspection of existing chemicals). The publication 'Fire Protection Guide on Hazardous Materials' by the National Fire Protection Agency (7th ed1978) gives the melting point of the substance as 105°C.  The slight differences in the value of the substance's melting point between the two results (i.e. 101 -103°C vs 105°C) could be due to possible variation in methods. However, no data were available in order to compare the methods or conditions.

·       boiling point investigation of 2,2’-Azobis (isobutyronitrile) is technically unfeasible as it decomposes before boiling.

·       density of 2,2’-Azobis (isobutyronitrile) is given as 'specific gravity' at a value of 1.05.

·       vapour pressure of 2,2’-Azobis (isobutyronitrile) was found to be 0.81 Pa at 25°C.

. partition coefficient of 2,2'-Azobis(2-methylpropionitrile) is reported to be 1.10 at 25°C

·       water solubility of 2,2’-Azobis (isobutyronitrile) was found to be 317.8 mg/L at 20°C.

.   surface tension is a scientifically unjustified test as it is not a desired property of the material.

·       flash point of 2,2’-Azobis (isobutyronitrile) does not require testing as the substance is solid at room temperature.

·       auto flammability of 2,2’-Azobis (isobutyronitrile) is scientifically unjustified as the substance is considered to present a danger of explosion.

·       flammability of 2,2’-Azobis (isobutyronitrile) is scientifically unjustified as the substance is considered to present a danger of explosion.

·       explosiveness: the substance 2,2’-Azobis (isobutyronitrile) was found to be sensitive in the thermal and shock sensitivity tests; the substance is considered to present a danger of explosion.

·       oxidising properties test for 2,2’-Azobis (isobutyronitrile) is scientifically unjustified as the substance is considered to present a danger of explosion.

. stability in organic solvents and identity of relevant degradation products: the results of the solubility of 2,2'-Azobis (isobutyronitrile) published in the Merck Index (13th edition 2001) is that in MEOH, at 0°C, 20°C and 40°C is 1.8, 4.96 & 16.06 g/100ml respectively; in EtOH at 0°C, 20°C and 40°C it is 0.58, 2.04 and 7.15 g/100ml respectively. The publication also states that the substance can explode when dissolved in Acetone.

. dissociation constant test does not need to be performed as the substance doesn't contain a ionisable functional group.

. viscosity does not need to be tested; the test is technically not feasible as the substance is a solid