Alpha Isomethyl Ionone
Aroma Chemical Base Note CAS 127-51-5
Soft, powdery violet with an orris character and a dry, woody sandalwood facet. Elegant and skin close, it rounds violet, carnation and woody floral accords.
Odor profile
| Note | Base Note |
| Descriptor 1 | Floral |
| Descriptor 2 | Violet |
| Descriptor 3 | Woody |
| Odor Impact1 | 90 |
| Tenacity1 | 175 h |
| Tenacity2 | 124 h |
1 Source: PerfumersWorld
2 Source: The Good Scents Company
Both tenacity figures are blotter life. The two labs use different evaluation protocols, so the numbers are not directly comparable — read them as two independent readings, not as a contradiction.
Identification
| CAS Number | 127-51-5 |
| INCI Name | 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one |
| Category | Aroma Chemical |
| Formula | C14H22O |
| Mol. Weight | 206.32 |
| IUPAC Name | (E)-3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one |
| InChIKey | JRJBVWJSTHECJK-PKNBQFBNSA-N |
Synonyms
Isoraldiene, Methyl Ionone, Alpha-methyl Ionone, Methyl ionone Alpha, Gamma, Alpha-iso, 4-(2,2,6-Trimethyl-2-cyclohexenyl)3-methyl-3-buten-2-one, Methyl-alpha-ionone, Iraldein-gamma, Raldeine-gamma 4-(2,6,6-Trimethyl-2-cyclohexen-1-yl)-3-methyl-3-buten-2-one, Raldeine gamma, Noviraldiol, iso Methyl alpha ionone, gammaMethyl ionone, alpha iso Methyl ionone, Iraldeine gamma, Alpha-Iso-Methylionone, Alpha Iso-Methylionone, 3-buten-2-one, 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-, (3E)-, gammanolene, iraldeine gamma (Givaudan), iso iraldeine pure (Givaudan), irisantheme (Givaudan), meth ionone gamma A tocopherol (IFF), meth ionone gamma coeur (IFF), meth ionone gamma pure (IFF), alpha-iso methyl ionone, iso-alpha-methyl ionone, gamma-methyl ionone (so called), methyl ionone gamma, methyl ionone gamma A (IFF), methyl ionone gamma coeur (IFF), methyl ionone gamma extra, methyl ionone gamma pure, methyl ionone gamma regular, methyl ionone gamma supreme, methyl ionone gamma suprime, (E)-3-methyl-4-(2,6,6-trimethyl-1-cyclohex-2-enyl)but-3-en-2-one (50% min.), (3E)-3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one, 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one
Physical and chemical data
| Boiling Point | 231.5 °C |
| Density | 0.925 |
| Refractive Index | 1.498 |
| Vapor Pressure | 0.006000 mmHg @ 20.00 C. |
| LogP | 3.3 |
| Solubility | alcohol; dipropylene glycol; paraffin oil |
| Appearance | CBI; Liquid; Dry Powder; Liquid |
Regulatory status
IFRA maximum concentrations
| Category | Use | Limit in the finished product |
|---|---|---|
| Category 1 | Lip products, toys | 5.4 % |
| Category 2 | Deodorants, antiperspirants | 1.6 % |
| Category 3 | Eye products | 32 % |
| Category 4 | Fine fragrance | 30 % |
| Category 5A | Body lotion | 7.6 % |
| Category 5B | Face cream | 7.6 % |
| Category 5C | Hand cream | 7.6 % |
| Category 5D | Baby creams, oils | 7.6 % |
| Category 6 | Oral care, mouthwash | 18 % |
| Category 7A | Rinse-off hair products | 61 % |
| Category 7B | Leave-on hair products | 61 % |
| Category 8 | Intimate and baby wipes | 3.2 % |
| Category 9 | Soap, shampoo, rinse-off | 59 % |
| Category 10A | Household care, hand contact | 100 % |
| Category 10B | Aerosol air fresheners | 100 % |
| Category 11A | Intended skin contact | 100 % |
| Category 11B | Minimal skin contact | 100 % |
| Category 12 | No skin contact, candles | Not restricted |
| IFRA Amendment | 49 |
| Restriction Type | Restriction / Specification |
| Critical Effect | Dermal Sensitization |
| Specification | Pseudo methyl ionones (CAS numbers 26651-96- 7, 72968-25-3, 1117-41-5) should not be used as fragrance ingredient as such. A level of up to 2% of Pseudo methyl ionones as an impurity in Methyl ionones is accepted. Page 189 of 709 Amendment 49 Methyl ionone, mixed isomers 2020 (Amendment 49) 3/4 IFRA STANDARD |
EU allergen declaration
| Substance | Share |
|---|---|
| 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one | 100 % |
Substances that must be named in the ingredient list under Annex III of Regulation (EC) 1223/2009, as amended by Regulation (EU) 2023/1545. Where a range was given, the upper bound is shown.
All figures on this page are guide values collected from public reference works and supplier declarations. They differ between batches, origins and qualities. The data sheet of your own supplier is always the authoritative document for the material you actually use.