[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials, storage methods, applications of halides

Halide Properties

Halides are compounds formed by combining halogen elements with other elements. Common halogens include fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). These compounds are diverse in nature, but generally have some commonalities. Halides are mostly ionic compounds, especially when they are combined with alkali and alkaline earth metals, such as sodium chloride (NaCl) and calcium fluoride (CaF2). Ionic halides have a high melting point and boiling point, and are highly soluble in water and highly conductive. Halides may decompose under the action of light and heat, especially some organic halides are prone to photochemical reactions under ultraviolet radiation. There are significant differences in chemical stability, solubility, melting point, etc. between different halides, which are due to the electronegativity and ionic radius of halogen atoms.

Halide Uses

Halides are used in a wide range of applications, covering many fields such as industry, medicine, agriculture and daily life. Sodium chloride is one of the most common halides and is widely used in the food and chemical industries. Fluorides such as sodium fluoride (NaF) are often used in toothpaste to prevent tooth decay. Bromides such as potassium bromide (KBr) have important applications in photography and pharmaceutical manufacturing. Iodides such as potassium iodide (KI) are used in the preparation of iodine and radioactive iodine isotopes. Organic halides such as chloroform (CHCl3) and Freon have important applications in medical anesthesia and refrigerants, respectively. The versatility of halides makes them indispensable chemicals for various industries.

Upstream raw materials

The production of halides relies on abundant upstream raw materials, which are mainly derived from minerals and seawater in nature. For example, sodium chloride is mainly extracted from seawater and salt lakes, obtained through evaporation and crystallization processes. The main raw material of fluoride is fluorite (CaF2), which is widely found in the earth's crust. The upstream raw materials of bromine are brine and salt lakes containing bromine, in which the extraction of bromine is usually achieved by oxidation and stripping. Iodide is mainly extracted from seaweed and iodine ore, and iodine is usually separated by oxidation. The upstream feedstocks for the production of organic halides involve petrochemical products, such as ethylene and methane, which are produced by halogenation reactions. Stable upstream feedstock supply is the basis for the sustainable development of the halide industry.

Downstream Products

The downstream products of halides are diverse and play a key role in various industries. In industry, sodium chloride is not only used in the production of chlorine and hydrogen, but also used in the manufacture of sodium hydroxide, soda ash and other chemical products. Downstream products of fluorides such as sulfur hexafluoride (SF6) are used as insulation gases in the power industry. Bromide downstream products are widely used in flame retardants, pharmaceutical intermediates and pesticides. The downstream products of iodide involve disinfectants, nutritional supplements and X-ray contrast agents. Organic halides such as tetrachloroethylene (C2Cl4) are used as dry cleaning solvents, while chlorofluorocarbons (CFCs) are used as refrigerants and blowing agents. The diversity and complexity of the downstream products of halides reflect their importance in modern industry.

storage method

The storage methods of halides vary due to their chemical nature. Generally speaking, halides need to be stored in a dry, cool environment, avoid humidity and high temperature. Common halides such as sodium chloride are relatively stable and can be stored in sealed containers to prevent moisture absorption. Fluorides such as hydrogen fluoride (HF) are highly corrosive and need to be stored in polytetrafluoroethylene (PTFE) or stainless steel containers and kept well ventilated. Volatile halides such as bromine and iodine should be stored in brown glass bottles, protected from light to prevent decomposition. Organic halides such as chloroform should be stored away from light and away from sources of fire. Scientific and reasonable storage method is the key to ensure the safe use and long-term preservation of halides.

Conclusion

As an important class of chemical substances, halides have important research and application value for their properties, uses, upstream and downstream raw materials and storage methods. Because of their unique chemical and physical properties, different halides play their respective roles in industry, medicine and daily life. From the acquisition of upstream raw materials to the diversity of downstream products, to the choice of storage methods, the various links of the halide industry chain are closely linked, forming a complex and efficient system. Understanding and mastering this knowledge will not only help to promote the research and application of halides, but also provide scientific basis and technical support for the development of related industries.