Phosphorus trichloride is highly toxic; it may cause death or permanent injury. Contact is highly irritating to the skin, eyes, and mucous membranes, and the material is an irritant through oral and inhalation exposure.
Heat it under reflux to expel dissolved HCl, then distil it. It has been further purified by vacuum fractionation several times through a -45o trap into a receiver at -78o. [Forbes Inorg Synth II 145 1946.] HARMFUL VAPOURS.
Phosphorus trichloride is a strong reducing agent that may ignite combustible organic materials upon contact. May generate flammable and potentially explosive gaseous hydrogen upon contact with many common metals (except nickel and lead). Reactions with water are violent and produce heat and flashes of fire [AAR, 1999]. Gives intensely exothermic reactions with iodine monochloride [Mellor 2, Supp. 1:502. 1956]. Several laboratory explosions have been reported arising from mixtures with acetic acid, along with other acids, sulfuric acid and derivatives, carboxylic acids, etc. These have been ascribed to poor heat control allowing the formation of phosphine [J. Am. Chem. Soc. 60:488. 1938]. Ignites when mixed with hydroxylamine [Mellor 8:290. 1946-47]. Causes an explosion on contact with nitric acid [Comp. Rend. 28:86]. Phosphorus trichloride is incompatible with many common oxidants such as: sodium peroxide, fluorine, chromyl chloride, iodine chloride, to name a few. Isopropanol can react with PCl3, forming toxic HCl gas. (Logsdon, John E., Richard A. Loke., "Isopropyl Alcohol." Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 1996.)
Phosphorus trichloride will react violently with water, producing heat and toxic and corrosive fumes. When heated to decomposition, Phosphorus trichloride emits highly toxic fumes of chlorides and phosphorus oxides. Phosphorus trichloride may ignite other combustible materials. Reacts violently with water. Reacts explosively with acetic acid, aluminum, chromyl chloride, diallylphosphite and allyl alcohol, dimethyl sulfoxide, fluorine, hydroxylamine, iodine monochloride, lead dioxide, nitric acid, nitrous acid, organic matter, potassium, and sodium. Avoid contact with water, steam, or acids. Hazardous polymerization may not occur.
As of phosphorus oxychloride; manufacture of POCl3, PCl5; producing iridescent metallic deposits.
Phosphorus trichloride is prepared by reacting white phosphorus with dry chlorine present in limited quantity. Excess chlorine will yield phosphorus pentachloride, PCl5.
P4 + 6Cl2 → 4PCl3
P4 + 10Cl2 → 4PCl5
The compound is prepared in a retort attached to inlet tubes for dry chlorine and dry carbon dioxide and a distillation flask. White phosphorus is placed on sand in the retort. All air, moisture, and any phosphorus oxide vapors present in the apparatus are expelled by passing dry carbon dioxide.
Dry chlorine is then introduced into the apparatus. If a flame appears on phosphorus it indicates presence of excess chlorine. In that event, the rate of chlorine introduction should be decreased. For obtaining phosphorus trichloride, flame should appear at the end of the chlorine-entry tube. The trichloride formed is collected by condensation in the distillation flask. A soda lime tube is attached to the apparatus to prevent moisture entering the flask.
Phosphorus trichloride also can be prepared by reducing phosphorus oxychloride vapors with carbon at red heat:
POCl3 + C → PCl3 + CO
A colorless or slightly yellow fuming liquid with a pungent and irritating odor resembling that of hydrochloric acid. Causes severe burns to skin, eyes and mucous membranes. Very toxic by inhalation, ingestion and skin absorption. Reacts with water to evolve hydrochloric acid, an irritating and corrosive gas apparent as white fumes.
Phosphorus trichloride is used to prepare phosphine and other phosphorus compounds; used during electrodeposition of metal on rubber and for making pesticides, surfactants, gasoline additives, plasticizers, dyestuffs, textile finishing agents, germicides, medicinal products, and other chemicals.