General Description
A white crystalline solid. Specific gravity 2.477. Decomposes below 100°C.
Reactivity Profile
POTASSIUM PERSULFATE(7727-21-1) is an oxidizing agent. Noncombustible but accelerates the burning of combustible material. POTASSIUM PERSULFATE(7727-21-1) plus a little potassium hydroxide and water released sufficient heat and oxygen to ignite a polythene (polyethylene) liner in a container. [MCA Case History 1155. 1955].
Air & Water Reactions
Water soluble. Slowly decomposed by water. The salt rapidly liberates oxygen when heated, and especially so when wet.
Hazard
Strong irritant and oxidizing agent. Fire risk
in contact with organic materials.
Health Hazard
Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or death. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause pollution.
Potential Exposure
Potassium persulfate is used as a
bleaching and oxidizing agent; it is used in redox polymeri-
zation catalysts; in the defiberizing of wet strength paper
and in the desizing of textiles. Soluble in water.
Fire Hazard
These substances will accelerate burning when involved in a fire. Some may decompose explosively when heated or involved in a fire. May explode from heat or contamination. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, includ-
ing resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medi-
cal attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is recommended for 24?48 hours
after breathing overexposure, as pulmonary edema may be
delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or
other inhalation therapy.
Shipping
UN1492 Potassium persulfate, Hazard Class:
5.1; Labels: 5.1-Oxidizer.
Incompatibilities
A strong oxidizer. Incompatible with
combustible, organic or other readily oxidizable materials;
sulfur, metallic dusts, such as aluminum dust; chlorates and
perchlorates. Attacks chemically active metals. Keep away
from moisture.
Description
Potassium persulfate, is composed of white crystals that are soluble in water, and it decomposes below 212°F (100°C). Potassium persulfate is a dangerous fire risk in contact with organic materials. It is a strong oxidizing agent and an irritant, with a four-digit UN identification number of 1492. The primary uses are in bleaching, as an oxidizing agent, as an antiseptic, as a polymerization promoter, and in the manufacture of pharmaceuticals.
Waste Disposal
Use large volumes of
reducing agents (bisulfites, e.g.). Neutralize with soda ash
and drain into sewer with abundant water.
Physical properties
Colorless or white crystals; triclinic structure; density 2.477 g/cm3; stable in solid crystalline form; decomposes on heating, evolving oxygen; completely decomposes at about 100°C; sparingly soluble in cold water 1.75 g/100mL at 0°C; moderately soluble at ordinary temperature, 5.29 g/100 mL at 20°C;aqueous solution acidic and unstable, decomposing slowly at room temperature and more rapidly when the solution is warmed; insoluble in alcohol.
Preparation
Potassium persulfate can be prepared by electrolysis of a mixture of potassium sulfate and potassium hydrogen sulfate at a high current density:
2KHSO4→K2S2O8+ H2
Also, the compound can be prepared by adding potassium hydrogen sulfate,KHSOto an electrolyzed solution of ammonium hydrogen sulfate, NH4HSO4.
Flammability and Explosibility
Nonflammable
Agricultural Uses
Potassium sulphate, also called sulphate of potash, is a
white crystalline material, moderately hygroscopic,
available in fine, granular and semi-granular forms. It
contains 48 to 54% potassium (as K2O) and supplies 17 to
20 % of sulphate. Chloride-sensitive crops like tobacco,
grapes and potato require chloride-free potassium
fertilizers. Therefore, these crops are fertilized with
potassium sulphate, although this is more expensive than
potassium chloride. These three crops, being major
crops, account for about 7% of the total potash
consumption. For best results, potassium sulphate should
contain at least 50 % potash by weight.
Potassium sulphate occurs in nature as 'langbeinite' ,
a double sulphate of potassium and magnesium
(K2SO4?2MgSO4) and made from burkeite
(Na2CO3?2Na2SO4), kainite (KCl?MgS04?3H2O) or
potassium chloride (KCl) as follows:
When applied to soil, potassium ion from the watersoluble
potassium sulphate is retained in the soil colloids
and not easily leached out. This makes potassium
sulphate an excellent fertilizer, useful for all soils and
crops while sowing or before sowing. It is also a safe
ingredient of powdered, mixed fertilizers.
Purification Methods
Crystallise the persulfate twice from distilled water (10mL/g) and dry it at 50o in a vacuum desiccator. Its solubility in H2O is 1.6% at 0o, 4.5% at 20o, and 7.2% at 30o. An aqueous solution decomposes on long standing with evolution of O2 and formation of KHSO4. It is a powerful oxidising agent. Store it at ~10o. [Fehér in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 390 1963.]
