2-Butynoic acid

Synonym(s):Tetrolic acid

CAS NO.：590-93-2
Empirical Formula: C4H4O2
Molecular Weight: 84.07
MDL number: MFCD00004363
EINECS: 209-695-7
SAFETY DATA SHEET (SDS)
Update Date: 2025-09-25 17:15:13

What is 2-Butynoic acid?

Chemical properties

white to yellow powder

The Uses of 2-Butynoic acid

2-Butynoic acid is used as an intermediate in organic synthesis and pharmaceuticals. It is used as a synthon in various reactions, which includes cylcoalkylation of phenols to flavones and chromones. It is involved in the cyclization of gamma-butyrolactones. It is also used in the synthesis of Z-trisubstituted olefins through μ-alkylation. It plays an important role in the preparation of chirally pure 1,2,3,4-tetrahydroisoquinoline analogs, which finds application as anti-cancer agents.

The Uses of 2-Butynoic acid

Synthon employed in a variety of reactions, including cycloacylation of phenols to flavones and chromones,1 and cyclization to γ-butyrolactones.2

General Description

The rotational spectrum of 2-butynoic acid was measured by pulsed supersonic-jet Fourier transform microwave spectroscopy.

Properties of 2-Butynoic acid

Melting point:	78-80 °C (lit.)
Boiling point:	200-203°C
Density	0,9641 g/cm³
refractive index	1.3918 (estimate)
Flash point:	200-203°C
storage temp.	Sealed in dry,2-8°C
solubility	water: soluble50mg/mL, clear to very slightly hazy, colorless to very faintly yellow
pka	2.62(at 25℃)
form	Powder
color	White to yellow
Water Solubility	Soluble in water. Slightly soluble in methanol and chloroform.
BRN	1740205
CAS DataBase Reference	590-93-2(CAS DataBase Reference)
NIST Chemistry Reference	2-Butynoic acid(590-93-2)
EPA Substance Registry System	2-Butynoic acid (590-93-2)

Safety information for 2-Butynoic acid

Signal word	Danger
Pictogram(s)	Corrosion Corrosives GHS05
GHS Hazard Statements	H314:Skin corrosion/irritation
Precautionary Statement Codes	P260:Do not breathe dust/fume/gas/mist/vapours/spray. P280:Wear protective gloves/protective clothing/eye protection/face protection. P363:Wash contaminated clothing before reuse. P303+P361+P353:IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.