Overview [1]

Sodium monofluorophosphate (MFP) is a white powdery solid with a melting point of approximately 626 ℃. It is easily soluble in water and has strong hygroscopicity, with a solubility of 42% in water at 25 ℃. There is no rusting effect, and the pH value of a 2% aqueous solution is 6.5-8.0. The aqueous solution undergoes slow hydrolysis when boiling, which can lead to a decrease in bound fluorine and an increase in free fluorine, resulting in a decrease in purity. Acidic substances can catalyze the hydrolysis of MFP; When there are strong alkaline or acidic solutions, or cations that can form insoluble fluorides or low solubility orthophosphate, hydrolysis will accelerate. Decahydrate can be obtained by crystallization from a 0 ℃ aqueous solution. If the crystallization water is removed by heating, it will lead to hydrolysis. Multiple extractions with ethanol or other organic solvents can yield anhydrous sodium monofluorophosphate.

Figure 1 Characteristics of Sodium Monofluorophosphate

Biological activity

Sodium monofluorophosphate is a competitive inhibitor of pyruvate kinase and alkaline phosphatase, with Ki values of 3.4 mM and 69 μ M, respectively. It also irreversibly inhibits phosphorylase phosphatase, with Ki values of 0.5 mM. Monofluorophosphate (1 mM) was applied to serum-free monolayer cultures, resulting in a 3-fold increase in the proliferation rate of chicken embryo skull cells. 30 μ M Monofluorophosphate acts on cranial bone cells, promoting the activity of DNA and alkaline phosphatase. 30 μ M Monofluorophosphate was applied to cultured intact skulls, increasing DNA activity, alkaline phosphatase activity, and collagen production by 143%, 186%, and 151%, respectively.

Nature

White crystals or powders. Melting point 625 ℃. The saturated aqueous solution contains 42% Sodium monofluorophosphate at 25 ℃. The pH value of a 2% dilute solution is 6.5-8. The decahydrate (Na2P03F-10H20) can be obtained by crystallization from a 0 ℃ aqueous solution. If the crystallization water is removed by heating, it will lead to hydrolysis. Anhydrous sodium monofluorophosphate can be obtained by multiple extractions with ethanol or other organic solvents.

Manufacturing method

Melting continuous method: Mix the theoretical amount of sodium fluoride and sodium hexametaphosphate evenly, continuously add them to a graphite-lined reactor, heat and melt them, and cool the continuously flowing material (air cooling) to produce the finished product of Sodium monofluorophosphate.

Purpose

Used as an anti-caries agent and tooth desensitizer, it generally accounts for 0.7% to 0% of toothpaste formulas 76%, currently, foreign countries have replaced sodium fluoride and gained an advantage in competition with stannous fluoride. It is also used for cleaning metal surfaces and as a flux, as well as for manufacturing special glass. Also used as a fungicide and preservative.

Security

Sodium monofluorophosphate should be stored in a cool, ventilated, dry, clean, and non-toxic warehouse. Packaged in a sealed container and not mixed with acidic substances for storage. During transportation, it should be protected from rain and not mixed with toxic or harmful substances. Handle with care during loading and unloading to prevent packaging damage. Under the conditions of this standard, Sodium monofluorophosphate the shelf life is one year. Packaged in cardboard drums lined with polyethylene plastic bags, with a net weight of 5kg or 25kg per drum. When a fire breaks out, water, sand, and various fire extinguishers can be used to extinguish it. Toxicity and protection: The LD50 (oral test, rat) of this product is 570mg/kg. Accidental ingestion of undiluted powder can cause spasms and coma. Inhalation or contact with eyes or skin can irritate, and prolonged contact with the skin can lead to excessive inhalation of this substance. To prevent long-term inhalation of this substance, it is necessary to strictly control the dust content in the atmosphere and regularly test the urine of workers in environments with this dust. When working, it is necessary to wear gloves, face masks, and protective goggles to prevent dust from coming into contact with the eyes and skin. If the eyes, mouth, or skin are contaminated with dust, immediately rinse with plenty of water, and in severe cases, seek medical attention immediately[2].