Phosphorus bromide is a colorless chemical fluid with a pungent odor and a chemical formula of PBr3. It is produced by exposing red phosphorus to bromine with careful attention paid to the volumetric relationship between the two to prevent the formation of phosphorus pentabromide. There are several industrial uses of phosphorus bromide, which include the manufacture of a range of pharmaceuticals such as alprazolam and fenoprofen. Another of the common industrial uses of phosphorus bromide is the manufacture of the fire suppression agent PhostrEX®. Phosphorus bromide should be treated with extreme caution as it is corrosive, toxic, and high reactive with a range of other elements.
A carefully controlled exposure of red phosphorus to bromide produces a colorless fluid chemical known as phosphorus bromide or phosphorus tribromide (PBr3). The relationships between the volumes of the two reagents in the process is carefully controlled with the phosphorus component being maintained at a higher level than the bromide. This is done to prevent the formation of the extremely corrosive solid, phosphorus pentabromide (PBr5). The chemical has a powerful, irritating odor and freely emits large volumes of fumes. The fluid may, under certain circumstances, exhibit a hazy or cloudy appearance.
There are several industrial uses of phosphorus bromide in the pharmaceutical manufacturing and chemical industries. In the pharmaceutical industry, the chemical is used in the manufacture of a number of well-known formulations, including alprazolam, methohexital and fenoprofen. One of the common industrial uses of phosphorus bromide in the chemical field is the fire suppression agent PhostrEX®. Developed by Eclipse Aviation, this agent is a direct replacement for the undesirable greenhouse gas Halon in cabin and engine fire suppression systems on commercial aircraft. In use, the agent quickly breaks down into ozone-friendly phosphorus acid and hydrogen bromide.
Although most industrial uses of phosphorus bromide are considered to be safe, it should be used with caution, as the chemical exhibits several hazardous characteristics. It is corrosive, although not as much so as phosphorus pentabromide, and is toxic and corrosive to metals and human tissue. The fumes it emits can cause severe nose, throat, and lung irritation and accidental contact with the eyes may lead to permanent blindness. Phosphorus bromide also reacts violently with warm water and a number of other elements including alcohols, strong base substances, and oxidizing agents. In certain conditions, particularly at temperatures above 320° Fahrenheit (160° Celsius), the chemical also produces phosphine, which may explode when exposed to air.