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Annex II Entry 1667 03/11/2021

Diisooctyl phthalate

Diisooctyl phthalate is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 1667

Chemical identity and properties

PubChem 2D chemical structure for CAS 27554-26-3
CAS 27554-26-3PubChem CID 33934

Diisooctyl phthalate

Diisooctyl phthalate is a phthalate ester and a diester. — ChEBI

IUPAC name
bis(6-methylheptyl) benzene-1,2-dicarboxylate
Molecular formula
C24H38O4
Molecular weight
390.6 g/mol
Exact mass
390.27700969 Da
XLogP3
8.5
Topological polar surface area
52.6 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
4
Covalent units
1
Defined stereocentres
0

Also known as

Isooctyl phthalateDiopDi-iso-octyl phthalateHexaplas M/OCorflex 880Phthalic acid, diisooctyl esterFlexol Plasticizer DIOPDiisooctyl 1,2-benzenedicarboxylate
16 more reported names
1,2-Benzenedicarboxylic acid, diisooctyl esterPhthalic acid, bis(6-methylheptyl)esterAI3-27697-X (USDA)HEXAPLAS DIOPJAYFLEX DIOP6A121LGB40UNEM 5005NSC-6381Diisooctylphthalatedi-isooctyl phthalateRefChem:9202751,2-bis(6-methylheptyl) benzene-1,2-dicarboxylate248-523-5Genomoll 100Bis(6-methylheptyl) phthalate131-20-4
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

Diisooctyl phthalate

Chemical / IUPAC name

Diisooctyl phthalate

Regulatory information

Regulation

(EU) 2021/1902

See every entry this act set

Key data

CAS
27554-26-3
EC
248-523-5
Annex
II
Entry number
1667

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

What Annex II means for Diisooctyl phthalate

Diisooctyl phthalate is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).

Frequently asked questions

Yes. Diisooctyl phthalate is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 27554-26-3 is the unique numerical identifier assigned to Diisooctyl phthalate by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record Diisooctyl phthalate

This page summarizes one Annex II record for Diisooctyl phthalate from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for Diisooctyl phthalate, but confirm any final regulatory decision against the current official annex wording and source files.

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