Outline
Potassium persulfate (Formula is K2S2O8) is also known as potassium peroxydisulfate, molecular weight is 270.32, decomposition temperature is 50-60℃, it is white, odorless crystal, it is soluble in water, insoluble in alcohol, it has strong oxidizing, it is commonly used as bleaching agents, oxidizing agents, it can be used as the polymerization initiator, it almost does not absorb moisture, it has good stability at room temperature, it is easy to be stored, and it has the advantages of convenience and safety, etc. . Applications involves polymerization initiator, circuit board cleaning and etching, copper and aluminum surface activation, modified starch, pulp and textile bleaching and desizing low temperature, circulating water purification treatment systems, oxidative degradation of harmful gases, low formaldehyde adhesive stick together accelerated oxidation of ethanol and aromatic hydrocarbons, disinfectants, hair dye decolorization.
The above information is edited by the chemicalbook of Wang Xiaodong.
Half-life
80℃-1.5 hours; 70℃-7.7 hours; 60℃-33 hours; 45℃-292 hours; 35℃-1600 hours.
Recrystallization
Potassium persulfate dissolves in 30℃ water, cools, then the recrystallized product can be obtained, it is filtered and dried under reduced pressure in the presence of calcium chloride.
Solubility in water(g/100ml)
Grams which dissolves in per 100 ml of water: 4.7g/20 ℃.
The main application areas
Potassium persulfate is mainly used as initiator and strong oxidizing agents.
Initiator:
Potassium persulfate is the initiator of latex or solution polymerization of acrylic monomers, vinyl acetate, vinyl chloride and other product, and it is also the initiator of styrene, acrylonitrile, butadiene and the like emulsion for copolymerisation.
Strong oxidizing agent:
1. It is used as desizing agent and bleach activator.
2. It is used for oxidative degradation of harmful substances in pool and closed circular loop in water.
3. It can be applied in the production of starch modifier and applied in the production of adhesive and coating agent.
4. It can be applied in the branched-chain oxidation, alcohol and aromatic hydroxy oxidation.
5. It is one of the basic constituent of hair dyes, it plays the role of decolorization.
Toxicity
The amount is not specified (FAO/WHO, 2001).
Potassium persulfate powder has stimulating effect on nasal mucosa, packaging should be ventilated to prevent dust. Labour protection appliance should be dressed at work.
Storage precautions
Potassium persulfate is non-flammable, it is combustion-supporting which due to it can release of oxygen, storage environment must be dry and clean, well-ventilated. Pay attention to moisture and rain, it should not be transported in rain. Keep away from fire, heat and direct sunlight. It should be kept sealed packaging, labels should be intact and clear. It should be stored separately with flammable or combustible materials, organic compounds, as well as rust, small amount of metal, and other reducing substance, it should avoid mix to prevent causing decomposition of potassium persulfate and explosion.
Chemical properties
It is colorless or white triclinic crystalline powder. It is soluble in water, the solubility is 1.75g/100ml water at 0℃, the solubility is 5.3g/100ml water at 20℃. It is insoluble in alcohol. Queous solution is acidic.
Uses
It can be used as gluten agent of wheat flour.
It is mainly used as a disinfectant and fabric bleach. It can be used as industrial oxidant in dyes and inorganic salts. It can be used as emulsion polymerization initiators in synthetic rubber industry. It can be used as polymerization accelerator in synthetic resin. In addition, it can also be used in the steel, photographic industry and medicine.
It can be used as analytical reagents, oxidants and plastic initiator, it can also be used in the film photofinishing.
The above information is edited by the chemicalbook of Wang Xiaodong.
Production method
Potassium sulfate method
Ammonium sulfate and sulfuric acid formulates to form liquid electrolyte, it is decontaminated by electrolysis, HSO4-can discharge and generate peroxydisulfate acidat in the anode, and then reacts with ammonium sulfate to generate ammonium persulfate, Then replacement reaction can happen when potassium is added . The finished product of potassium persulfate can be obtained after cooling, separation, crystallization, drying.
Anode reaction: 2HSO4-2e → H2S2O8
Cathodic reaction: 2H ++ 2e → H2 ↑
(NH4) 2SO4 + H2S2O8 → (NH4) 2S2O8 + H2SO4
(NH4) 2S2O8 + K2SO4 + H2SO4 → K2S2O8 + 2NH4HSO4
It can be derived by replacement reaction with ammonium persulfate potassium sulfate, then it goes through cooling, separation, crystallization, drying.
Toxicity grading
Mid toxicity.
Acute toxicity
Oral-rat LD50: 802 mg/kg.
Explosive hazardous characteristics
It can explode when mixes with reductant, sulfur, phosphorus; It can explode when be heated, impacted, and meets fire.
Flammability hazard characteristic
Thermal decomposition can get oxygen; toxic fumes of nitrogen oxides can generate after combustion.
Storage characteristics
Treasury should have ventilation and be low-temperature drying; loading and unloading should be light; it should be stored separately with organic matter, reducing agents, sulfur, phosphorus combustibles.
Extinguishing agent
Mist of water, sand, foam.
Professional standards
TWA 2 mg/m.
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.
Chemical Properties
colourless odourless crystals or white powder
Chemical Properties
Potassium persulfate is a colorless or white,
odorless crystalline material.
Physical properties
Colorless or white crystals; triclinic structure; density 2.477 g/cm
3; 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.
Uses
Potassium persulfate?is a powerful oxidant, commonly used to initiate polymerizations. Potassium Persulphate used for bleaching and textile desizing, as an oxidizing agent and antiseptic, in purification of ammonium sulfate, and in the manufacture of soap and pharmaceuticals. It is also used as al laboratory oxidant and photography chemical. It is a food additive.
Uses
Potassium persulfate is used to initiate the polymerization of styrene to form monodispersed, surfactant-free polystyrene spheres. Potassium persulfate is used as an oxidant to generate 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation to measure the antioxidant activities of natural compounds.
Uses
Bleaching fabrics, soaps; in photography under the name Anthion to remove last traces of thiosulfate from plates and paper; in analytical chemistry.
Preparation
Potassium persulfate can be prepared by electrolysis of a mixture of potassium sulfate and potassium hydrogen sulfate at a high current density:
2KHSO
4→K
2S
2O
8+ H
2Also, the compound can be prepared by adding potassium hydrogen sulfate,KHSOto an electrolyzed solution of ammonium hydrogen sulfate, NH
4HSO
4.
General Description
A white crystalline solid. Specific gravity 2.477. Decomposes below 100°C.
Air & Water Reactions
Water soluble. Slowly decomposed by water. The salt rapidly liberates oxygen when heated, and especially so when wet.
Reactivity Profile
Potassium persulfate is an oxidizing agent. Noncombustible but accelerates the burning of combustible material. Potassium persulfate 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].
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.
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.
Flammability and Explosibility
Non flammable
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 K
2O) 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
(K
2SO
4?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.
Safety Profile
Moderately toxic by
ingestion. An irritant and allergen. A
powerful oxidtzer. Flammable when
exposed to heat or by chemical reaction.
Can react with reducing materials. It
liberates oxygen above 100' when dry or @
about 50' when in solution. When heated to
decomposition it emits highly toxic fumes of
SOx,, S2O8, and K2O.
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.
Shipping
UN1492 Potassium persulfate, Hazard Class:
5.1; Labels: 5.1-Oxidizer.
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.]
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.
Waste Disposal
Use large volumes of
reducing agents (bisulfites, e.g.). Neutralize with soda ash
and drain into sewer with abundant water.
