''N''-Isopropyl-''N''′-phenyl-1,4-phenylenediamine (often abbreviated IPPD) is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...
commonly used as an
antiozonant
An antiozonant, also known as anti-ozonant, is an organic compound that prevents or retards damage caused by ozone. The most important antiozonants are those which prevent degradation of elastomers like rubber. A number of research projects stud ...
in rubbers, particularly those used for
tire
A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which t ...
s. Like other
p-phenylenediamine
''p''-Phenylenediamine (PPD) is an organic compound with the formula C6H4(NH2)2. This derivative of aniline is a white solid, but samples can darken due to air oxidation. It is mainly used as a component of engineering polymers and composites lik ...
-based antiozonants it works by virtue of its low
ionization energy
Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive Electric charge, charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged a ...
, which allows it to react with
ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
faster than ozone will react with rubber.
This reaction converts it to the corresponding
aminoxyl radical (R
2N–O•), with the ozone being converted to a hydroperoxyl radical (HOO•),
these species can then be scavenged by other antioxidant
polymer stabilizers Polymer stabilizers (British: polymer stabilisers) are chemical additives which may be added to polymeric materials, such as plastics and rubbers, to inhibit or retard their degradation.
Common polymer degradation processes include oxidation, UV- ...
.
IPPD is prone to process called
blooming
Bloom or blooming may refer to:
Science and technology Biology
* Bloom, one or more flowers on a flowering plant
* Algal bloom, a rapid increase or accumulation in the population of algae in an aquatic system
* Jellyfish bloom, a collective ...
, where it migrates to the surface of the rubber. This can be beneficial to the tire, as ozone attacks the tire surface and blooming therefore moves the antiozonant to where it is most needed, however this also increases the
leaching
Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to:
*Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amoun ...
of IPPD into the environment. Many tire producers have moved to using
6PPD instead, as this migrates more slowly. Oxidation of IPPD converts the central phenylenediamine ring into a
quinone
The quinones are a class of organic compounds that are formally "derived from aromatic compounds benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with ...
.
Safety
IPPD is a human
allergen
An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies.
In technical ter ...
. It is the compound responsible for coining the term "Volkswagen Dermatitis". There is some preliminary evidence for it being harmful to fish.
See also
*
''N'',''N''′-Di-2-butyl-1,4-phenylenediamine - a phenylenediamine based antioxidant used as a fuel additive
References
{{DEFAULTSORT:Isopropyl-N'-phenyl-1,4-phenylenediamine, N-
Antioxidants
Diamines
Plastics additives