Ammonium bromide (NH ₄ Br) is an important inorganic bromide with stable chemical properties (melting point 382 ℃, easily soluble in water), and has been applied in multiple industries due to its unique physicochemical properties. The following is an analysis of its main application areas and specific functions:
1、 Pharmaceutical industry: Sedatives and pharmaceutical intermediates
1. Central nervous system drugs
       Function: Ammonium bromide was used as a sedative in the early medical field, and its bromide ions can inhibit excessive excitation of the central nervous system, used to treat diseases such as neurasthenia, insomnia, and epilepsy (now gradually replaced by safer drugs).
        System of action: Bromine ions regulate the ion permeability of neuronal cell membranes, reducing the conduction speed of nerve impulses and thus producing a sedative effect.
2. Pharmaceutical intermediates
       Application scenario: As a bromine source involved in drug synthesis, for example:
       Preparation of antibiotics containing bromine (such as bromhexine, used for expectorant treatment), analgesics, and central nervous system drugs;
       Introducing bromine atoms through bromination reactions in organic synthesis improves the lipid solubility or biological activity of drugs.
2、 Photography and photosensitive materials: film development and fixation
1. Black and white film developer additive
       Function: In traditional photography, ammonium bromide is used as an inhibitor of the developing solution to control the development speed and contrast.
       Principle: Bromine ions compete with developers (such as metol and hydroquinone) to adsorb on the surface of silver halide crystals, suppressing overdevelopment, avoiding an increase in film haze, and improving image clarity.
2. Auxiliary components of fixing solution
       Function: A litter amount of ammonium bromide can adjust the pH value of the fixing solution, enhance the solubility of sodium thiosulfate (fixing agent) in unexposed silver halide, and ensure complete film fixation.
3、 Chemical and Organic Synthesis: Catalysts and Bromine Sources
1. Organic synthesis catalyst
       Application scenario: As a catalyst or catalyst carrier in esterification and alkylation reactions, for example:
       Catalyze the esterification reaction of carboxylic acids and alcohols (such as the preparation of ethyl acetate from acetic acid and ethanol) to increase the reaction rate;
As an auxiliary reagent of Lewis acid in Friedel Crafts reaction, it promotes the alkylation or acylation of aromatic hydrocarbons.
2. Raw materials for bromide preparation
       Usage: As a supply source for bromide ions, used for the production of other bromides, such as:
       Preparation of potassium bromide (for spectral analysis) and calcium bromide (additive for oilfield drilling fluid);
       Synthesize organic bromides (such as brominated hydrocarbons, used in the production of pesticides and flame retardants).
4、 Petroleum and natural gas industry: drilling fluid additives
1. Preparation of high-density drilling fluid
       Function: Ammonium bromide can form a high-density solution (density up to 1.5-2.0 g/cm ³) when dissolved in water, which is used to prepare oil well drilling fluid, adjust the density of drilling fluid to balance formation pressure, and prevent blowout accidents.
       Advantages: Compared with inorganic salts such as sodium chloride, ammonium bromide solution has a higher density and lower corrosiveness, making it suitable for deep-sea or high-pressure oil and gas well operations.
2. Completion fluid and workover fluid
       Application: In the process of oil and gas well completion or repair, ammonium bromide solution can be used as a working fluid to protect the reservoir from damage, while also having good anti swelling performance (inhibiting clay mineral expansion).
5、 Agriculture and Livestock: Disinfectants and Pesticides
1. Agricultural disinfectant
       Function: The aqueous solution of ammonium bromide has a certain bactericidal ability and can be used for soil disinfection (such as preventing soil borne diseases) or crop surface sterilization (such as post harvest treatment of vegetables and fruits).
       Principle of action: Bromine ions can damage the integrity of microbial cell membranes and inhibit their metabolic activity.
2. Preservatives for livestock breeding
       Usage: Add a litter amount of ammonium bromide to animal feed or drinking water as a preservative to inhibit bacterial growth and extend the shelf life of feed (in compliance with food safety standards).
6、 Laboratory and Analytical Chemistry: Reagents and Reference Materials
1. Analytical reagents
       Application: Used for preparing bromide ion standard solutions, calibrating ion selective electrodes (ISE), or serving as a reference substance for titration analysis (such as silver nitrate titration method for determining bromide ion content).
2. Organic synthesis experiment
       Function: As a bromine source in the laboratory, participate in organic synthesis experiments such as halogenation reactions and Grignard reactions, such as preparing brominated aromatic hydrocarbons or brominated alkanes.
7、 Other application areas
1. Flame retardant material additives
       Function: After compounding with antimony compounds, ammonium bromide can be used as a flame retardant in plastics (such as polystyrene), rubber, and textiles. It can suppress flame spread by capturing free radicals during combustion (but its use has been restricted in some scenarios due to environmental disputes).
2. Fireworks and blasting industry
       Usage: A litter amount of ammonium bromide can be used as a component of fireworks to adjust flame color (produce light yellow flames) or as a fume suppressant to reduce combustion fume.

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