5-Methylsalicylic acid

Synonym(s):p-Cresotic acid;2-Hydroxy-5-methylbenzoic acid

CAS NO.：89-56-5
Empirical Formula: C8H8O3
Molecular Weight: 152.15
MDL number: MFCD00002461
EINECS: 201-918-6
SAFETY DATA SHEET (SDS)
Update Date: 2026-01-13 11:26:59

What is 5-Methylsalicylic acid?

Chemical properties

5-Methylsalicylic acid is a white to beige powder that is soluble in basic water and in polar organic solvents. At neutral pH, the acid exists as 5-methylsalicylate Its functional groups include a carboxylic acid and a phenol group. It is one of four isomers of methylsalicylic acid.

The Uses of 5-Methylsalicylic acid

Toxicity is similar to salicylic acid. 5-Methylsalicylic acid is used in manufacturing of dyes.

The Uses of 5-Methylsalicylic acid

5-Methylsalicylic acid was used in generation of o-sulfate conjugates in situ and their analysis by ultra-performance liquid chromatography-time-of-flight mass spectrometry.

Preparation

5-Methylsalicylic acid can be prepared by hydroxylation of 3-methylbenzoic acid.

General Description

5-Methylsalicylic acid exhibits a significant cross-reactivity during fluorescent polarization immunoassay for salicylates in serum.

Purification Methods

Crystallise the acid from H2O. [Beilstein 10 H 227, 10 II 134, 10 III 516, 10 IV 610.]

Properties of 5-Methylsalicylic acid

Melting point:	150-154 °C (lit.)
Boiling point:	234.6°C (rough estimate)
Density	1.2143 (rough estimate)
refractive index	1.4945 (estimate)
storage temp.	Sealed in dry,Room Temperature
form	Powder
pka	pK1:4.08 (25°C)
color	White to beige
Water Solubility	21.9g/L(100 ºC)
Merck	14,2582
BRN	1909076
CAS DataBase Reference	89-56-5(CAS DataBase Reference)
NIST Chemistry Reference	5-Methylsalicylic acid(89-56-5)

Safety information for 5-Methylsalicylic acid

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H302:Acute toxicity,oral H315:Skin corrosion/irritation H319: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. P270:Do not eat, drink or smoke when using this product. P301+P312:IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell. 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.