3-Hydroxy-2-naphthoic acid Property

Melting point:

218-221 °C(lit.)

Boiling point:

283.17°C (rough estimate)

Density 

1.43 g/cm3 (23℃)

refractive index 

1.7160 (estimate)

Flash point:

>150°C

storage temp. 

Sealed in dry,Room Temperature

solubility 

0.072g/l practically insoluble

pka

3.02±0.30(Predicted)

form 

Fine Crystalline Powder

color 

Yellow to beige-brown

Water Solubility 

PRACTICALLY INSOLUBLE

λmax

395nm(H2O (pH 3.5))(lit.)

Merck 

14,4835

BRN 

744100

CAS DataBase Reference

92-70-6(CAS DataBase Reference)

NIST Chemistry Reference

2-Naphthalenecarboxylic acid, 3-hydroxy-(92-70-6)

EPA Substance Registry System

3-Hydroxy-2-naphthoic acid (92-70-6)

Safety

Hazard Codes 

Xn,Xi

Risk Statements 

22-36-36/37/38

Safety Statements 

26-37/39

WGK Germany 

1

RTECS 

QL1755000

TSCA 

Yes

HS Code 

29182910

Hazardous Substances Data

92-70-6(Hazardous Substances Data)

Toxicity

The acute oral LD50 of 3-Hydroxy-2-naphthoic acid in rats was 823-1040 mg/kg bw.

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H302Harmful if swallowed

H318Causes serious eye damage

H335May cause respiratory irritation

H412Harmful to aquatic life with long lasting effects

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P273Avoid release to the environment.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P301+P312IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

3-Hydroxy-2-naphthoic acid Chemical Properties,Usage,Production

Chemical Properties

yellow to beige-brown fine crystalline powder. 3 -Hydroxy-2-naphthoic acid [92-70-6], BON acid, C11H8O3, Mr 188.17, mp 222℃, forms pale yellow crystals from aqueous ethanol. Alkaline solutions have a green fluorescence. Aqueous ferric chloride produces a blue color, and warming with CHCl3– NaOH results in a green color. Oxidation with alkaline permanganate gives 2-carboxyphenylglyoxylic acid and then phthalic acid. Dry distillation produces dibenzoxanthone. Bromination gives the 4,7-dibromo derivative; nitration, the 4-nitro derivative; and sulfonation with oleum, the 5,7-disulfonic acid derivative.

Uses

3-Hydroxy-2-naphthoic acid is mainly used as intermediate for the production of dyes and pigments. Further uses are as intermediate for insecticides and pharmaceuticals (ECB, 2000).

Uses

2-hydroxy-3-naphthoic acid (BON) is coupled with diazo compounds and their calcium salts are bright red bleed resistance pigments. The somewhat higher cost manganese salt shows better exterior durability than the calcium or barium salts. The BON red pigments are characterized by an extremely high degree of color stability, resistance to acids and alkalies and are nontoxic.

Definition

ChEBI: 3-Hydroxy-2-naphthoate is a naphthoic acid.

Preparation

3 -Hydroxy-2-naphthoic acid is invariably by the Kolbe – Schmitt reaction of carbon dioxide with the dried sodium salt of 2-naphthol at 220 – 260℃. Many improvements in both process and equipment have been developed. The main problems are removal of the 50 % unreacted 2-naphthol and avoidance of a tarry byproduct. Yields of 80 % based on the amount of 2-naphthol consumed are possible despite the low conversion.

Hazard

Irritant.

Purification Methods

Crystallise it from water or acetic acid. The S-benzyisothiuronium salt has m 216-217o (from EtOH). It forms many metal complex salts. [Beilstein 10 H 333, 10 III 1084.]