3-Methyl-4-isothiazolecarboxylic acid
[CAS# 15903-66-9]

Identification

• Name: 3-Methyl-4-isothiazolecarboxylic acid
• Synonyms: 3-Methylisothiazole-4-carboxylic acid
• Molecular Formula: C₅H₅NO₂S
• Molecular Weight: 143.16
• CAS Registry Number: 15903-66-9
• EC Number: 692-328-1

Properties

• Solubility: Sparingly soluble (13 g/L) (25 ºC), Calc.^*
• Density: 1.418±0.06 g/cm³ (20 ºC 760 Torr), Calc.^*
• Melting point: 235.5-237.5 ºC^**
• Boiling point: 91.5-93 ºC (3 Torr)^***
• Refractive index: 1.5139 (589.3 nm 24.5 ºC)^***
• Flash point: 64.1±25.4 ºC, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2016 ACD/Labs)

^** Howe, Robert K.; Journal of Organic Chemistry 1978, V43(19), P3736-42.

^*** NL 6607796 1966.

Safety Data

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2A	H319
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	4	H312