7 April 2024 08:26
القاهرة, مصر

جديد

EGP0

Chinese name: boric acid
English name: boric acid

Biological activity of boric acid
Boric acid is a preservative. Boric acid is tasteless.

Physical and chemical properties of boric acid
Density 1.4±0.1 g/cm3
Boiling point: 219-220 °C (9.7513 mmHg)
Melting point 169 °C
Molecular formula H3BO3
Molecular weight 61.833
Precise quality6616.666666666666
PSA 60.69000
LogP -0.29
Appearance characteristics colorless or white odorless crystalline solid
Steam pressure 2.6 mm Hg (20 °C)
Refractive index 1.385
Storage condition
Store in a dry, clean, cool and ventilated warehouse. Stay away from fire and heat sources. It should be stored separately from alkali and potassium, and should not be mixed.
Don’t share and transport with toxic substances. Stability
1. In fact, it is a hydrate of boron oxide, which is a white powdery crystal or a scalelike shiny crystal with a triclinic axis. It has a greasy feel and no smell. No smell. It tastes slightly sour and bitter with sweetness. There is a feeling of satiny in contact with the skin. There is no change in exposed air. Can volatilize with water vapor. When heated to 100 ~ 105℃, one molecule of water is lost to form metaboric acid, which is transformed into pyroboric acid when heated for a long time at 104 ~ 160℃, and anhydrous substance is formed at higher temperature. The pH of 0.1mol/L aqueous solution is The solubility in water increases with the increase of temperature, and can be volatilized with water vapor. The solubility in inorganic acids is smaller than that in water. When heated to 70 ~ 100℃, metaboric acid is gradually dehydrated, pyroboric acid is generated at 150 ~ 160℃, and boric anhydride (B2O3) is generated at 300℃. 3. Oral administration is toxic, and acute poisoning may occur. Early symptoms are vomiting, diarrhea, rash, central nervous system first excited and then inhibited, and there may be meningeal irritation and kidney injury. The staff should be well protected. If they touch the skin and eyes carelessly, they should immediately wash them with plenty of water. The solubility of 100g water is 2.66g(0℃), 4.9g(20℃), 8.7g(40℃), 14.8g(60℃), 23.6g(80℃) and 39.7g(100℃). Soluble in ethanol and glycerol. Insoluble in ether. In a dry air stream or in an air bath at 80℃ for several days, it becomes metaboric acid HBO2. The metaboric acid obtained at this time is one of three metamorphoses, and the product with melting point of 176℃ (orthorhombic system, relative density of 1.78) is obtained. After heating this product at 140℃ for a long time, the monoclinic system with melting point of 2009℃ (relative density of 204) is obtained. After further heating, it becomes a cubic product with a melting point of 236℃ (relative density of 2.48). No matter which variant is dissolved in water, it becomes boric acid. When metaboric acid is burned, it becomes B2O3. Water solubility 49.5 g/L (20 ºC)