Sodium hydrosulfite

  • Sodium dithionite
  • Sodium sulfoxylate
Formula
Na2S2O4
Structure
Description
Sodium dithionite is a whitish to light yellow crystalline solid having a sulfur dioxide-like odor.
Uses
Reducing agent to strip certain dyes from fabrics and in vat dyeing, bleaching agent for ground wood pulp, soap, straws, sugar.

Registry Numbers and Inventories.
CAS
7775-14-6
EC (EINECS/ELINCS)
231-890-0
EC Index Number
016-028-00-1
EC Class
May cause fire; Contact with acids liberates toxic gas; Harmful
R 7 22 31
S 7/8 26 28 43
RTECS
JP2100000
UN (DOT)
1384
Merck
12,8771
Beilstein/Gmelin
47441 (G)
EPA OPP
78202
Swiss Giftliste 1
G-5445
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
Na2O4S2
Formula mass
174.11
Melting point, °C
100
Vapor density (air=1)
3.6
Density
2.19 g/cm3 (20 C)
Solubility in water
Very soluble

Hazards and Protection.
Storage
Keep away from heat, sparks, and flame. Keep away from sources of ignition. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Keep away from water. Do not expose to air. Store protected from moisture. Store under an inert atmosphere.
Handling
Use only in a well ventilated area. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Avoid contact with heat, sparks and flame. Avoid ingestion and inhalation. Handle under an inert atmosphere. Store protected from air. Do not allow contact with water. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames. Keep from contact with moist air and steam.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Sweep up or absorb material, then place into a suitable clean, dry, closed container for disposal. Scoop up with a nonsparking tool, then place into a suitable container for disposal. Avoid generating dusty conditions. Remove all sources of ignition. Place under an inert atmosphere. Do not get water inside containers.
Stability
Stable under normal temperatures and pressures.
Incompatibilities
Strong oxidizing agents, moisture, air.
Decomposition
Carbon monoxide, oxides of sulfur, carbon dioxide.

Fire.
Flash Point,°C
>100
Autoignition, °C
> 200
Fire fighting
Flood with water.
Fire potential
Flammable/combustible material.
Hazards
May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard.
Combustion products
Fire will produce irritating, corrosive and/or toxic gases.
Health
2
 
Flammability
3
 
 
Reactivity
1
 

Health.
Poison_Class
3
Exposure effects
Effects may be delayed.
   Ingestion
May cause nausea, vomiting, abdominal pain, and increased salivation.
   Inhalation
May cause allergic respiratory tract irritation. Inhalation of dust may cause respiratory tract irritation. Olfactory fatigue may occur. Can produce delayed pulmonary edema.
   Skin
May cause skin irritation and possible burns.
   Eyes
May cause lacrimation (tearing), blurred vision, and photophobia. May cause chemical conjunctivitis and corneal damage.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid. DO NOT use mouth-to-mouth respiration.
   Skin
Get medical aid if irritation develops or persists. Wash clothing before reuse. Flush skin with plenty of soap and water.
   Eyes
Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.

Transport.
UN number
1384
Response guide
Hazard class
4.2
PRTC
T
Packing Group
II
 
HS Code
2831 10 00
 
Std. Transport #
4916179