Industrial grade, Food grade 98%, 99% Potassium iodide CAS 7681-11-0

 What is Potassium iodide?

Potassium iodide, also known as potassium iodide, is the iodide of potassium and one of the most classic inorganic salts used in the detection of iodine. Its chemical formula is usually written as:

KI (CAS No.: 7681-11-0, EINECS No.: 231-659-4, molecular weight approximately 166.00, iodine content approximately 76.45%)

Potassium iodide is a colorless or white crystalline powder at room temperature, odorless, with a salty and bitter taste. It has a melting point of approximately 681℃, a boiling point of approximately 1330℃, and a relative density of approximately 3.12. It is extremely soluble in water (approximately 1280-1440 g/L), and its aqueous solution is neutral or slightly alkaline. It is slightly soluble in ethanol. Potassium iodide is hygroscopic and will precipitate free iodine and turn yellow upon prolonged exposure to light or oxidizing agents.

From a molecular structure perspective, potassium iodide is a typical ionic crystal, composed of potassium ions (K+) and iodide ions (I-) bonded together by ionic bonds. Iodine atoms have a large atomic radius and low electronegativity, and iodide ions are easily oxidized to elemental iodine (I-→I2). Therefore, potassium iodide is not only a stable and easily absorbed iodine source, but also has mild reducing properties and can dissolve elemental iodine to generate triiodide ions (I3-)—a property that makes it a core substance for iodometric titration analysis and the preparation of iodine tincture .

Potassium iodide is chemically hygroscopic in the air. Iodide ions can be easily oxidized under the action of light, acid and oxidizing agents, releasing free iodine and turning yellow. Therefore reagent grade products must be stored in air-tight, light-proof and moisture-proof conditions and must not be mixed with oxidizing agents.

“Non-food grade and non-industrial grade potassium iodide” refers to products intended for scientific research and testing, and not for use in food processing or large-scale industrial applications. These are mostly reagent grade (analytical grade, superior grade, conforming to national standards of chemical reagents). More weight is given to the following indicators than to food grade and industrial grade products:

Loss on drying (moisture)

Moisture must be tightly controlled to ensure product stability, flowability and accuracy of measurement.

Iodate and free iodine

Free iodine and iodate

Oxidation products such as free iodine and iodate are important quality indicators for reagent-grade products and may affect color and analytical performance of the product.

Heavy metal limits (lead, arsenic, barium, etc.)

For analytical reliability of reagent-grade reagents, a low impurity background is necessary.

 What are the uses of Potassium iodide?

1. Iodized salt (nutritional fortifier, core application)

Potassium iodide is a key source of iodine in iodized salt and is used to make iodized salt. According to the national standard of my country “Iodine Content in Edible Salt” (GB 26878), the average iodine content of iodized salt should be 20-30 mg/kg. The most widespread application of potassium iodide is the iodized salt , which in my country is a public health strategy for the prevention and elimination of the iodine deficiency disorders .

2. Fortified foods including modified milk powder

Potassium iodide can be used to fortify food categories such as milk powder with iodine, according to GB 14880 “Standard for the Use of Food Fortifiers”, which facilitates specific groups of people to supplement iodine nutrition through daily food and improve dietary iodine intake.

3. Iodine fortification in infant formula

Iodine is an essential nutrient for infant formula. Potassium iodide is used for iodine fortification in infant formula and complementary foods. Its use must comply with the infant formula food standards such as GB 10765 to ensure the iodine nutrition and growth and development of infants.

4. Health foods and iodine dietary supplements

Potassium iodide is used as a raw material for iodine-containing health foods and dietary supplements, providing a convenient way for people with insufficient iodine intake to supplement their iodine intake. Products must be registered or filed and labeled with the appropriate population and dosage.

5. Aquaculture and feed (indirect contact)

Potassium iodide is used as an iodine supplement in aquaculture industry chain for aquaculture and animal feeds. The fish, shrimp, meat, eggs and dairy products we eat may be indirectly involved in their raising.

7. Chemical Synthesis Catalysts and Reaction Aids (Core Application)

Potassium iodide is a catalyst and auxiliary agent for a variety of organic synthesis reactions, used in esterification, carbonylation, alkylation and other reaction systems. It is also an important catalyst for the synthesis of carbonate compounds, serving the fine chemical and new materials industries.

8. Analytical Chemistry Reagents (Iodometric Method)

Potassium iodide is a fundamental reagent in iodometric analysis (iodine titration), used to determine vitamin C, sulfites, dissolved oxygen, and various redox substances. It is also a core raw material for preparing iodine standard solutions and starch-potassium iodide test paper, and is widely used in analytical laboratories.

9. Feed additives (animal iodine nutrition)

Potassium iodide is used as an iodine additive in livestock, poultry, and aquatic feed to provide animals with essential iodine nutrition, maintain thyroid function and normal growth, and is a commonly used iodine source in feed premixes.

10. Photosensitive Materials and Imaging Industry

Potassium iodide is an auxiliary component of silver halide photosensitive emulsions, used in the preparation of traditional photosensitive materials such as film and photographic paper, and continues to be used in the fields of image archive restoration and special photosensitive materials.

11. Electroplating and Surface Treatment (Cyanide-Free Gold Plating Complexing Agent)

Potassium iodide is used as a complexing agent in cyanide-free gold plating processes. It forms stable complexes with gold ions and is used for gold plating of jewelry, electronic connectors and precision devices. It is an important auxiliary agent in green electroplating processes.

12. Disinfection and preservation products

Potassium iodide serves as a solubilizer for tincture of iodine and a stabilizer for iodine-based disinfectant products. It helps iodine to dissolve, disperse and remain stable and is an essential excipient in traditional disinfectant and antiseptic preparations.

13. Teaching Experiments and Popular Science Applications

Potassium iodide is a commonly used reagent in classic chemical experiments such as the "iodine clock experiment" and iodometric titration. It is used in chemistry teaching and demonstrations in middle schools and universities to help students understand redox reactions and reaction kinetics.

It should be noted that non-food grade and non-industrial grade specifications do not mean "risk-free": reagent grade products have high purity but are not managed according to food standards and are strictly prohibited from being consumed; protective equipment should be worn during experimental operations to avoid dust inhalation and skin contact.

Summarize

Potassium iodide (KI, CAS No. 7681-11-0) is a colorless or white crystalline powder, highly soluble in water, and a classic iodine source compound containing approximately 76.45% iodine. It possesses both a stable iodine supply capacity and mild reducing properties. In daily life, we encounter it through disinfectants in home medicine cabinets, testing and laboratory services, school experiments, and research institutions.