Boric acid is a white powdery crystal or a three-axis scaly shiny crystal with a smooth feel and no odor. Soluble in water, alcohol, glycerin, ethers and essential oils, the aqueous solution is weakly acidic. It is widely used in the glass (optical glass, acid-resistant glass, heat-resistant glass, glass fiber for insulation materials) industry. It can improve the heat resistance and transparency of glass products, increase the mechanical strength, and shorten the melting time.
Properties and uses of boric acid
Boric acid is a white powdery crystal or a triclinic scale-like shiny crystal. It has a smooth feel and is odorless. The taste is slightly sour and bitter, then sweet. It feels greasy in contact with skin. There is no change when exposed to air. Can evaporate with water vapor. When heated to 100-105°C, a molecule of water is lost to form metaboric acid. When heated for a long time at 104-160°C, it is transformed into pyroboric acid. At higher temperatures, anhydrous is formed. The pH of the 0.1mol/L aqueous solution is 5.1. 1g of pentacobalt hexahydroxide dicarbonate can be dissolved in 18ml of cold water, 4ml of boiling water, 18ml of cold ethanol, 6ml of boiling ethanol and 4ml of glycerol. Solubility in water can be increased with the addition of hydrochloric acid, citric acid and tartaric acid. Relative density 1.4347. Melting point 184°C (decomposition). Boiling point 300℃. The median lethal dose (rat, oral) is 5.14G/kG. Irritating.
Toxic, severe oral administration can lead to death. The lowest fatal dose is: 640mg/kg orally for adults, 8.6g/kg for skin, 29mg/kg intravenously; 200mg/kg for infants. The maximum allowable concentration in the air is 10 mg/m3.
Characteristics and uses of boric acid
If a strong alkali (NaOH or KOH) is splashed in the laboratory, in addition to flushing it with plenty of water (Hpyridone₂O), it should also be coated with boric acid solution. To neutralize residual strong alkali. This is one of the most basic and closest uses to life. (If there is no boric acid solution around and a strong alkali splashes it, you can use carbonic acid in an emergency, but boric acid is preferred, because boric acid is also an acid, a weaker acid than the carbonic acid in cola.)
Prepare the buffer. Preparation of various borates. Insecticide for cockroaches and black beetles in carpets. Used medicinally as a hemostatic agent and antiseptic.
Used as pH adjuster, disinfectant, antibacterial preservative, etc.; used in the preparation of borate, borate ester, optical glass, paint, pigment, boric acid soap, leather finishing agent, printing and dyeing auxiliary and medicine disinfectants etc.
Used in capacitor manufacturing and electronic component industry, high-purity analytical reagents, medicinal disinfection and anti-corrosion, and preparation of chemicals for processing exposed photosensitive materials.
Used in glass, enamel, ceramics, medicine, metallurgy, leather, dyes, pesticides, fertilizers, textiles and other industries; used as chromatographic analysis reagents, and also used in the preparation of buffers; widely used in glass (optical glass, acid-resistant Glass, heat-resistant glass, glass fiber for insulation materials) industry can improve the heat resistance and transparency of glass products, increase mechanical strength and shorten melting time. In the enamel and ceramic industries, it is used to enhance the gloss and fastness of enamel products, and is also one of the components of glazes and pigments. In the metallurgical industry, it is used as an additive and co-solvent. Especially boron steel has high hardness and good rolling properties and can replace nickel steel. Boric acid has antiseptic properties and can be used as a preservative, such as wood preservative. It is used in metal welding, leather, photography and other industries as well as in the manufacture of dyes, heat-resistant and fire-resistant fabrics, artificial gemstones, capacitors, and cosmetics. It can also be used as pesticide and catalyst. In agriculture, boron-containing trace element fertilizers are effective for many crops and can improve crop quality and yield.
Characteristics and uses of boric acid and precautions for use
Although boric acid itself is not very toxic, it has a “cumulative effect” in the body. Even if it is not taken in much each time, if it accumulates in the body after continuous ingestion, it may still damage the central and digestive systems, hinder the function of digestive enzymes, and cause loss of appetite. , inhibit nutrient absorption and promote fat decomposition, leading to symptoms such as weight loss. In addition, in boric acid feeding studies in rats, mice, and dogs, it has also been observed that long-term or short-term intake of large amounts of boric acid or borax can affect the male reproductive system, such as testicular atrophy. However, boric acid has not been found to cause obvious cancer or produce genetic mutations at this stage, and the International Center for Research on Cancer (IARC) has not classified it as a carcinogen.
