Diisononyl phthalate

DiNP; Phthalate di-iso-nonylester; formula: C6H4(COOC9H19)2 or C26H42O4; CAS Registry Number: 28553-12-0 and 68515-48-0
Structure of diisononyl phthalate
Source: PubChem
Identifier: CID 590836
URL: https://pubchem.ncbi.nlm.nih.gov/compound/590836#section=Structures

Mixture of phthalate diesters differing slightly in branching of the alcohol chains and main substitute of DEHP as plasticizer

The term diisononyl phthalate (DiNP) denominates a group of several phthalate diesters with slightly different branching of the alcohol chains. They are produced by esterification of phthalic acid with iso-nonyl alcohol. DiNP 1 (CAS 68515-48-0) is produced by the so called polygas process and contains more or less equal amounts of 3,4-, 4,6-, 3,6-, 3,5-, 4,5-, und 5,6-dimethyl heptanol-1. DiNP 2 (CAS 28553-12-0) is based on n-butene and its alcohol fraction consists mainly of alkyl substituted octanols, heptanols and hexanols. Active profiles and toxicology of both DiNP are very similar. For regulatory purposes they are therefore handled as one.

DiNP is a plasticizer mainly for PVC and is present for instance in floorings and wall coverings, carpets, shoe soles, tubes, cables and vinyl gloves. Further applications include rubber, dispersions, paints, lacquers, sealants, adhesives and packaging.

It is increasingly used as substitute of DEHP (diethylhexyl phthalate).

DiNP is not chemically bound in the polymer matrix and may outgas or be released upon contact with fluids or fats. When it enters the environment it is readily degraded. DiNP has a relatively high potential for bioaccumulation.

In chronic animal tests DiNP is toxic. Furthermore, toxicity on reproduction can not be excluded.

By precautionary principles the use of DiNP in toys has been forbidden, although no threats of human health has been proven so far.

For the Environmental Specimen Bank not the parent compound DiNP itself is analysed in human specimens but its major metabolites.


  • 7oxo-MiNP
    Mono(4-methyl-7-oxo-octyl)phthalate is a oxidised DiNP metabolite with functional oxo group.
  • 7OH-MiNP
    Mono(4-methyl-7-hydroxyoctyl)phthalate is a oxidised DiNP metabolite with functional hydroxyl group.
  • 7cx-MiNP
    Mono(4-methyl-7-carboxyheptyl)phthalate is a oxidised DiNP metabolite with functional carboxyl-group.


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Sampling area

Sampling period

1988 - 2015

Extended information

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