TiCl4

TiCl4, or titanium tetrachloride (titanium(IV) chloride), is an inorganic compound with the formula TiCl4. It is a colorless to pale yellow, volatile liquid at room temperature that fumes in air because of hydrolysis. It has a boiling point of about 136.4 °C and is highly reactive with water and oxygen, requiring handling under dry, inert conditions.

Production and appearance: Industrial TiCl4 is produced by direct chlorination of titanium-bearing oxides, such as TiO2 (rutile), with chlorine gas at elevated temperatures to give TiCl4 and O2: TiO2 + 2 Cl2 → TiCl4 + O2. The product is typically purified by distillation to remove impurities before use.

Chemical behavior: TiCl4 is a strong Lewis acid and hydrolyzes readily in moisture to form titanium dioxide (TiO2) and hydrogen chloride (HCl). In anhydrous media it forms adducts with bases and undergoes alcoholysis: TiCl4 + 4 ROH → Ti(OR)4 + 4 HCl, a reaction used to prepare titanium alkoxides for various applications.

Applications: TiCl4 serves as a key precursor in the production of titanium metal via the Kroll process, in which TiCl4 is reduced with magnesium to yield titanium metal. It is also a common catalyst precursor in Ziegler–Natta polymerization systems for producing polyolefins, typically after activation with organoaluminium compounds such as AlEt3. Additionally, TiCl4 is used to prepare titanium alkoxides for sol-gel chemistry and various organic synthesis applications.

Safety: TiCl4 is highly corrosive and reacts violently with water, liberating corrosive HCl gas. It fumes in air and should be handled in a fume hood under strictly anhydrous conditions with appropriate protective equipment.