3,3-Dimethylacrylic acid

Synonym(s):3,3-Dimethylacrylic acid;3-Methyl-2-butenoic acid;3-Methylcrotonic acid;Senecioic acid

CAS NO.：541-47-9
Empirical Formula: C5H8O2
Molecular Weight: 100.12
MDL number: MFCD00004366
EINECS: 208-782-7
SAFETY DATA SHEET (SDS)
Update Date: 2026-04-22 18:57:36

What is 3,3-Dimethylacrylic acid ?

Description

May be prepared by the action of alkalis or bases on the ester of α-bromoisovaleric acid; by condensation of acetone with malonic acid or bromoacetic ester; by oxidation of mesityl oxide with sodium hypochlorite.

Chemical properties

White to brown crystal

Chemical properties

3-Methylcrotonic acid has green, phenolic, dairy aroma

Occurrence

Reported found in the rhizomes of Senecio kaempferi Seib.; the corresponding ester occurs naturally in waste wort. Also reported found in raspberries, wheat bread, cocoa, coffee, black tea, Arctic bramble, and green and roasted maté.

The Uses of 3,3-Dimethylacrylic acid

Chemical Intermediates.

Definition

ChEBI: A methyl-branched fatty acid that is but-2-enoic acid bearing a methyl substituent at position 3.

Preparation

By the action of alkalis or bases on the ester of α-bromoisovaleric acid; by condensation of acetone with malonic acid or bromoacetic ester; by oxidation of mesityl oxide with sodium hypochlorite.

Synthesis Reference(s)

Journal of the American Chemical Society, 71, p. 3214, 1949 DOI: 10.1021/ja01177a079
Organic Syntheses, Coll. Vol. 3, p. 302, 1955
Tetrahedron Letters, 36, p. 2469, 1995 DOI: 10.1016/0040-4039(95)00285-K

Purification Methods

Crystallise the acid from hot water or pet ether (b 60-80o). [Beilstein 2 IV 1555.]

Properties of 3,3-Dimethylacrylic acid

Melting point:	65-70 °C (lit.)
Boiling point:	194-195 °C (lit.)
Density	0,969 g/cm³
refractive index	1.4226 (estimate)
FEMA	3187 \| 3-METHYLCROTONIC ACID
Flash point:	93°C
storage temp.	Keep in dark place,Sealed in dry,Room Temperature
solubility	Chloroform (Slightly), Methanol (Slightly)
form	Solid
pka	pK1:5.12 (25°C)
color	Off-White to Pale Orange
Odor	at 1.00 % in propylene glycol. green phenolic dairy
Water Solubility	Soluble in water, and methanol.
JECFA Number	1204
BRN	1720305
CAS DataBase Reference	541-47-9(CAS DataBase Reference)
NIST Chemistry Reference	2-Butenoic acid, 3-methyl-(541-47-9)
EPA Substance Registry System	2-Butenoic acid, 3-methyl- (541-47-9)

Safety information for 3,3-Dimethylacrylic acid

Signal word	Danger
Pictogram(s)	Corrosion Corrosives GHS05 Exclamation Mark Irritant GHS07
GHS Hazard Statements	H315:Skin corrosion/irritation H318:Serious eye damage/eye irritation H335:Specific target organ toxicity, single exposure;Respiratory tract irritation
Precautionary Statement Codes	P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P264:Wash hands thoroughly after handling. P264:Wash skin thouroughly after handling. P271:Use only outdoors or in a well-ventilated area. P280:Wear protective gloves/protective clothing/eye protection/face protection. P302+P352:IF ON SKIN: wash with plenty of soap and water. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.