Titanium tetrachloride

Description

Titanium ore was first discovered in 1791 in Cornish beach sands by an English clergyman, William Gregor. The actual identification of the oxide was made a few years later by a German chemist, M.H. Klaproth, who gave the metal constituent of this oxide the name titanium, after the Titans of Greek mythology. Pure metallic titanium was first produced in the early 1900s in 1910 by M.A. Hunter at Rensselaer Polytechnic Institute in cooperation with General Electric Company.
Titanium tetrachloride is an inorganic compound that is an important intermediate in the production of titanium metal and the pigment titanium dioxide. On contact with humid air, it forms opaque clouds of titanium dioxide (TiO2) and hydrogen chloride (HCl). Early attempts to isolate titanium metal from titanium tetrachloride were unsuccessful. The process was improved and commercialized by William Kroll of Luxembourg in the 1930s which involved the reduction of titanium tetrachloride with magnesium in an inert gas atmosphere. This process remains essentially unchanged today. The primary use of titanium tetrachloride is for titanium dioxide used in paints.
The production of titanium metal accounts for only 5% of annual titanium mineral consumption, with the remainder being used in the titanium pigment industry. Pigments are produced using either a sulfate process or a more environmentally acceptable carbochlorination process that converts TiO2 into TiCl4. The latter process also supplies the TiCl4 necessary for the production of titanium metal.

The Uses of Titanium tetrachloride

Titanium tetrachloride is used as an intermediate in the manufacture of titanium metal, titanium dioxide, titanous chloride pigments, iridescent glass, and artificial pearls and as a starting material for a variety of organic and inorganic titanium compounds. It is also used as a dye, a polymerization catalyst, and as a catalyst in many organic syntheses because of it acidity and oxophilicity in many applications in the chemical industry. Titanium tetrachloride was formerly used as a smokeproducing screen with ammonia for the military; however, due to its extremely irritating and corrosive qualities in both liquid and smoke formulation, military applications are rarely used. The conversion of tetrachloride to titanium metal takes place by the reduction of chloride with magnesium which yields titanium metal and magnesium chloride and is referred to as the Kroll process after its inventor:
2 Mg ＋ TiCl4→2 MgCl2 ＋ Ti