Naphthalene-2-sulfonic acid Property

Melting point:

124 °C

Boiling point:

317.43°C (rough estimate)

Density 

1.44 g/cm

vapor pressure 

2.33Pa at 20℃

refractive index 

1.4998 (estimate)

storage temp. 

Inert atmosphere,Room Temperature

solubility 

water: freely soluble(lit.)

form 

solid

pka

0.27±0.10(Predicted)

color 

White

Water Solubility 

Soluble in water.

Sensitive 

Hygroscopic

Merck 

6377

LogP

-0.944 at 23℃

CAS DataBase Reference

120-18-3(CAS DataBase Reference)

EPA Substance Registry System

2-Naphthalenesulfonic acid (120-18-3)

Safety

Hazard Codes 

C,F

Risk Statements 

35-34-11

Safety Statements 

26-36/37/39-45-16

RIDADR 

UN 2583 8/PG 2

WGK Germany 

1

RTECS 

QK1225000

Hazard Note 

Corrosive

TSCA 

Yes

HazardClass 

8

PackingGroup 

III

HS Code 

2904100090

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H290May be corrosive to metals

H314Causes severe skin burns and eye damage

Precautionary statements

P260Do not breathe dust/fume/gas/mist/vapours/spray.

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

P301+P330+P331IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.

P303+P361+P353IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower.

Naphthalene-2-sulfonic acid Chemical Properties,Usage,Production

Chemical Properties

Nondeliquescent, white plates.Soluble in water, alcohol, and ether. Combustible.

Uses

Naphthalene-2-sulfonic acid is used in making direct dyes, reactive des and employed as dye and agrochemical intermediates.

Uses

Starting point in the manufacture of β-naphthol, β-naphtholsulfonic acid, β-naphthylaminesulfonic acid, etc.

Preparation

Naphthalene-2-sulfonic acid is prepared by sulfonation of naphthalene.
Step: With naphthalene as raw material, 98% sulfuric acid is used as sulfonating agent, and it is obtained by sulfonation at 160-166 ℃. During the sulfonation process, a small amount of α-naphthalenesulfonic acid by-product is generated. By heating, the unstable α-naphthalenesulfonic acid can be hydrolyzed at 140-150 °C to remove the sulfonic acid group, and become naphthalene and sulfuric acid. Naphthalene can be blown out. During the hydrolysis of naphthalene, a small amount of lye should be added to neutralize part of the sulfuric acid. It also acts with naphthalenesulfonic acid to form β-naphthalenesulfonic acid sodium salt crystals, which can be filtered to obtain the finished product of Naphthalene-2-sulfonic acid.

Definition

ChEBI: Naphthalene-2-sulfonic acid is a naphthalenesulfonic acid in which the sulfo group is linked to position 2 of the naphthalene ring. It has a role as an environmental contaminant and a xenobiotic.

General Description

The fluorescence of 2-naphthalenesulfonic acid (NSA) is effectively quenched by colloidal silver via photoinduced interfacial electron transfer from the excited singlet of NSA to silver. Adsorption behavior of NSA on a conventional macroporous resin Amberlite XAD4 and hypercrosslinked resins NDA101 and NDA100 has been investigated.

Flammability and Explosibility

Non flammable

Purification Methods

Crystallise the acid from conc HCl. The S-benzylisothiuronium salt has m 192o (from aqueous EtOH). [Berger Acta Chem Scand 8 432 1954, Beilstein 11 H 171, 11 IV 527.]