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1,5-Naphthalenedisulfonic acid

CAS No.81-04-9
Chemical Name:1,5-Naphthalenedisulfonic acid
CBNumber:CB8346027
Molecular Formula:C10H8O6S2
Formula Weight:288.3
MOL File:81-04-9.mol

1,5-Naphthalenedisulfonic acid Property

Melting point 242.5°C (rough estimate)
Boiling point 400.53°C (rough estimate)
Density 1.7040
bulk density 900kg/m3
vapor pressure 0Pa at 25℃
refractive index 1.5630 (estimate)
storage temp. Store below +30°C.
pka -0.60±0.40(Predicted)
color Crystals or plates
PH 2.4 (20°C, 1g/L in H2O)
Water Solubility 90.52g/L at 25℃
LogP -0.94
CAS DataBase Reference 81-04-9(CAS DataBase Reference)
EWG's Food Scores 1
FDA UNII E8FPK78470
EPA Substance Registry System 1,5-Naphthalenedisulfonic acid (81-04-9)
UNSPSC Code 12352106
NACRES NA.22

Safety

Hazard Codes :C
Risk Statements :34
Safety Statements :22-24/25-45-36/37/39-26
RIDADR :UN 2585
WGK Germany :1
HazardClass :8
PackingGroup :III
HS Code :2904100090
Toxicity :LD50 orl-rat: 30 g/kg GISAAA 45(3),73,80

Hazard and Precautionary Statements (GHS)

Symbol(GHS)
Signal wordDanger
Hazard statements H314-H318
Precautionary statements P260-P280-P301+P330+P331-P303+P361+P353-P304+P340-P305+P351+P338-P310

1,5-Naphthalenedisulfonic acid Chemical Properties,Usage,Production

Chemical Properties Naphthalene-1,5-disulfonic acid [81-04-9]. Armstrong acid, C10H8O6S2, Mr 288.28, crystallizes as the tetrahydrate but dehydrates at 125 ℃ to give the anhydrous acid (mp 240 – 245℃). The disulfonic acid forms an anhydride when treated with oleum below 50℃. This anhydride reacts with ammonia to give a mixture of naphthalene-1,5-disulfonamide and naphthalene-1- sulfonamide-5-sulfonic acid. Treatment of the disodium salt of naphthalene-1,5-disulfonic acid with phosphorus pentachloride at 110℃ gives naphthalene-1,5-disulfonyl chloride (mp 184 ℃), which may also be prepared by chlorosulfonation of naphthalene. Reaction of an aqueous solution of naphthalene-1,5-disulfonic acid with bromide – bromate gives 1,5-dibromonaphthalene so readily that the yellow precipitate may be used to identify very low concentrations of the disulfonic acid.
Uses The disodium salt of naphthalene-1,5- disulfonic acid gives 1-hydroxynaphthalene-5- sulfonic acid or 1,5-dihydroxynaphthalene (see Section 3.3) by fusion processes. Further sulfonation of the disulfonated reaction mixture gives naphthalene-1,3,5-trisulfonic acid, and nitration leads to 1- and 2-nitronaphthalene-4,8-disulfonic acids as intermediates to the corresponding aminonaphthalene disulfonic acids. Naphthalene-1,5-disulfonic acid is an important stabilizer for diazo compounds.
Definition ChEBI: Naphthalene-1,5-disulfonic acid is a naphthalenesulfonic acid.
Production Methods Naphthalene is mixed with 20 % oleum at 20 – 35 C followed by gradual addition of 65 % oleum and further naphthalene alternately. After heating for 6 h at 55 C the reaction mixture is added to water, and the product is precipitated as the free acid by cooling or as the disodium salt by the addition of alkaline sodium sulfate. In each case, the isolated yield is ca. 53 %. The 1,6-disulfonic acid can be recovered from the filtrate. Higher yields of 4 have been reported for alternative processes; for example, solvent sulfonation with sulfur trioxide and chlorosulfonic acid in a solvent such as tetrachloroethylene [24] or sulfonation with oleum through a double screw-feed apparatus.
Flammability and Explosibility Not classified
Safety Profile Very low oral toxicity. Whenheated to decomposition it emits toxic fumes of SOx. Seealso SULFONATES.