ALPHA-ISO-METHYLIONONE

Synonym(s):α-Cetone;3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one;Isomethyl-α-ionone

CAS NO.：127-51-5
Empirical Formula: C14H22O
Molecular Weight: 206.32
MDL number: MFCD00034582
EINECS: 204-846-3
SAFETY DATA SHEET (SDS)
Update Date: 2026-05-28 02:48:59

What is ALPHA-ISO-METHYLIONONE?

Description

α-Isomethylionone has a fine violet and orris-like odor. This substance may be synthesized by condensation of citral with methyl ethyl ketone controlling the ratio between the n- and iso-forms; the methyl pseudo-ionone obtained is then subjected to ring closure, using strong alkali and high temperature (thus favoring the formation of the normal α- and β-methylionones) or with quaternary ammonium base (thus favoring the formation of wo-forms); See also monographs of α- and β-ionone and methyl α-, β-, and γ-ionones.

Chemical properties

α-Isomethylionone has a fine violet and orris-like odor.

Preparation

By condensation of citral with methyl ethyl ketone controlling the ratio between the n- and iso-forms; the methyl pseudoionone obtained is then subjected to ring closure, using strong alkali and high temperature (thus favoring the formation of iso-forms); See also monographs of α-, β-, and γ-ionones.

Definition

ChEBI: 3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one is a sesquiterpenoid.

Flammability and Explosibility

Not classified

Contact allergens

As a fragrance allergen, a-isomethylionone has to be mentioned by name in cosmetics within the EU.

Properties of ALPHA-ISO-METHYLIONONE

Boiling point:	121-122℃ (9 Torr)
Density	0.93 g/mL at 20 °C(lit.)
vapor pressure	0.22Pa at 20℃
refractive index	1.50188 (589.3 nm 20℃)
FEMA	2714 \| ALPHA-ISO-METHYLIONONE
storage temp.	Sealed in dry,Room Temperature
solubility	Chloroform (Slightly), DMSO (Slightly), Methanol (Slightly)
form	liquid
color	Light orange to Yellow to Green
Odor	at 10.00 % in dipropylene glycol. woody violet floral
Water Solubility	27.953mg/L at 25℃
JECFA Number	404
Stability:	Light Sensitive
EPA Substance Registry System	3-Buten-2-one, 3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)- (127-51-5)

Safety information for ALPHA-ISO-METHYLIONONE

Signal word	Warning
Pictogram(s)	Environment GHS09
GHS Hazard Statements	H411:Hazardous to the aquatic environment, long-term hazard
Precautionary Statement Codes	P273:Avoid release to the environment. P391:Collect spillage. Hazardous to the aquatic environment P501:Dispose of contents/container to..…