Comparison and selection of process technology schemes

At present, the main methods for producing bromine using hydrobromic acid are chlorine oxidation and hydrogen peroxide oxidation.

(1) Chlorine oxidation method

This method uses hydrobromic acid and chlorine gas as the main raw materials. Firstly, dilute the hydrobromic acid with water. The diluted hydrobromic acid is pumped into the top of the distillation tower through a feeding pump, and chlorine gas is introduced from the bottom of the distillation tower. The reaction temperature is controlled at 80 ℃, and the bromine generated by the oxidation of chlorine gas is distilled and blown out. After condensation and recovery, liquid bromine is obtained, which is then washed with water and refined to obtain bromine. The bottom material of the distillation tower is by-product hydrochloric acid, which is neutralized with liquid alkali and subjected to multi effect evaporation to obtain by-product sodium chloride.

This process uses highly toxic liquid chlorine as an oxidant. According to the "List of Hazardous Chemicals", liquid chlorine belongs to the second category of compressed gas and liquefied gas dangerous goods, and is also the third toxic gas among them, with high process hazard. The residual chlorine in this process is relatively high, which affects the downstream use of liquid bromine. This process produces a large amount of solid waste sodium chloride as a byproduct, which needs to be collected after neutralization, concentration, and dehydration, resulting in high energy consumption and difficult solid waste disposal.

(2) Hydrogen peroxide oxidation method

This method uses hydrobromic acid and 27.5% industrial hydrogen peroxide as the main raw materials. Firstly, transfer hydrobromic acid into an oxidation reactor, control the reaction temperature not to exceed 50 ℃, add a certain amount of hydrogen peroxide dropwise, and recover the liquid bromine generated by oxidation through distillation. After water separation and refining, liquid bromine is obtained.

This process uses green oxidant hydrogen peroxide to generate water after the reaction, with no other by-products and no residual chlorine in the product. The production process has low energy consumption and is environmentally friendly.

In summary, using hydrogen peroxide oxidation method is the preferred solution.

Physical and chemical properties

-Appearance: Colorless or slightly yellow transparent liquid.

-Odor: It has a stimulating sour taste.

-Solubility: Can be mixed with water, alcohol, and acetic acid, and is easily soluble in chlorobenzene.

-Density: 1.49g/cm ³ (47.5%) at 126 ℃.

-Melting point: -66.5 ℃.

-Boiling point: 126 ℃ (47%).

Chemical property

-Acidic: can undergo neutralization reaction with alkali to generate corresponding bromides and water.

-Oxidation: undergoes displacement reaction with metals, generating corresponding bromides while releasing hydrogen gas.

-Reductive: When exposed to air and sunlight, the color gradually darkens due to free bromine.

Preparation Method

-Laboratory method: Obtained by co heating sodium bromide and concentrated phosphoric acid.

-Industrial methods: include methanol method, sulfur dioxide method, and red phosphorus method.

Application area

-In the field of medicine: used for synthesizing anesthetics, sedatives, antidepressants, etc.

-In the industrial field, it is used to produce various inorganic and organic bromide raw materials, as well as good solvents for metal minerals, for high-purity metal extraction, etc.

-Other fields: used as analytical reagents, manufacturing fragrances, dyes, flame retardants, etc.

Packaging and Storage

-Packaging: Commonly available in 250kg/drum, 300kg/drum, and tank truck packaging.

-Storage: It should be stored in a cool, dry, and well ventilated place, away from fire and heat sources, sealed and stored separately from cyanides, alkalis, etc.

Safety precautions

-Health hazards: burns caused by skin contact, respiratory irritation caused by inhalation, and oral and gastric burns caused by ingestion.

-Leakage handling: Evacuate personnel, seal leaks, collect mixed materials such as sand or rinse with a large amount of water.