Why does CAS 141-05-9 appear in more than one EU cosmetic annex?

A substance identified by CAS 141-05-9 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts — for example, restricted under Annex III with specific conditions, while also appearing in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

How do I check if my formula contains a substance with CAS 141-05-9?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 141-05-9 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 141-05-9

Q: How do I use CAS 141-05-9 for compliance screening?

Cross-reference CAS 141-05-9 against your raw material specification sheets and CoA documents. When it appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met. All annex entries sharing this CAS number are listed on this page.

CAS 141-05-9 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

Check this CAS number Browse annexes

Chemical identity and properties

PubChem 2D chemical structure for CAS 141-05-9

CAS 141-05-9PubChem CID 5271566

Diethyl Maleate

Diethyl maleate is a maleate ester resulting from the formal condensation of both carboxy groups of maleic acid with ethanol. A colourless liquid at room temperature (m.p. -10C) with boiling point 220C at 1 atm., it is commonly used as a dienophile for Diels-Alder-type cycloaddition reactions in organic synthesis. It has a role as a glutathione depleting agent. It is an ethyl ester and a maleate ester. It is functionally related to an ethanol. — ChEBI

IUPAC name: diethyl (Z)-but-2-enedioate

Molecular formula: C8H12O4
Molecular weight: 172.18 g/mol
Exact mass: 172.07355886 Da
XLogP3: 0.9
Topological polar surface area: 52.6 Å²
Hydrogen-bond donors: 0
Hydrogen-bond acceptors: 4
Covalent units: 1
Defined stereocentres: 0

Also known as

DiethylmaleateMaleic acid, diethyl ester2-Butenedioic acid (2Z)-, diethyl esterDiethylester kyseliny maleinoveG81WQB56OLSTAFLEX DEMNSC-8394CHEBI:68508

16 more reported names

RefChem:133422diethyl maleic acid diester205-451-9Maleic acid diethyl ester2-Butenedioic acid (Z)-, diethyl esterDiethyl (Z)-2-butenedioatediethyl (2Z)-but-2-enedioate2-Butenedioic acid, diethyl ester, (Z)-2-Butenedioic acid, diethyl ester, (2Z)-Diethyl (2E)-2-butenedioate2-Butenedioic acid (2Z)-, 1,4-diethyl esterdiethyl (2Z)but-2-ene-1,4-dioateCAS-141-05-9CCRIS 941WLN: 2OV1U1VO24-02-00-02207 (Beilstein Handbook Reference)

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:68508
ChEMBL:CHEMBL2037000
EPA DTXSID:DTXSID8020464
PubMed:321785
PubMed:3825

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

Records for CAS 141-05-9

1 total

Annex

Entry

426

Diethyl maleate, when used as a fragrance ingredient

205-451-9

How CAS 141-05-9 is used on this site

CAS 141-05-9 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 141-05-9 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 141-05-9 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.

Check this CAS number

Tools & next steps

Check your formula

Scan a full INCI list, then use CAS 141-05-9 to cross-check any supplier documents behind the matched substances.

INCI Checker

Browse annexes

Browse all EU cosmetic regulation annexes by category.

All annexes

Search by name

Search for INCI names, aliases or related identifiers that sit alongside CAS 141-05-9 in your documentation.