Titanium tetrabromide is the
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one ele ...
with the
formula TiBr
4. It is the most volatile transition metal bromide. The properties of TiBr
4 are an average of TiCl
4 and TiI
4. Some key properties of these four-coordinated Ti(IV) species are their high Lewis acidity and their high solubility in nonpolar organic solvents. TiBr
4 is diamagnetic, reflecting the d
0 configuration of the metal centre.
Preparation and structure
This four-coordinated complex adopts a tetrahedral geometry. It can be prepared via several methods: (i) from the elements, (ii) via the reaction of TiO
2 with carbon and bromine (see
Kroll process The Kroll process is a pyrometallurgical industrial process used to produce metallic titanium from titanium tetrachloride. The Kroll process replaced the Hunter process for almost all commercial production.
Process
In the Kroll process, the Ti ...
), and (iii) by treatment of TiCl
4 with
HBr.
Reactions
Titanium tetrabromide forms adducts such as TiBr
4(
THF)
2 and
iBr5sup>−. With bulky donor ligands, such as
2-methylpyridine
2-Methylpyridine, or 2-picoline, is the compound described with formula C6H7N. 2-Picoline is a colorless liquid that has an unpleasant odor similar to pyridine. It is mainly used to make vinylpyridine and the agrichemical nitrapyrin.
Synthesis
...
(2-Mepy), five-coordinated adducts form. TiBr
4(2-MePy) is trigonal bipyramidal with the pyridine in the equatorial plane.
TiBr
4 has been used as a Lewis-acid
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
in
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
.
The tetrabromide and tetrachlorides of titanium react to give a statistical mixture of the mixed tetrahalides, TiBr
4−xCl
x (x = 0-4). The mechanism of this
redistribution reaction is uncertain. One proposed pathway invokes the intermediacy of
dimers.
Safety
TiBr
4 hydrolyzes rapidly, potentially dangerously, to release
hydrogen bromide
Hydrogen bromide is the inorganic compound with the formula . It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room tempe ...
, otherwise known as hydrobromic acid.
References
{{bromine compounds
Bromides
Titanium halides
Titanium(IV) compounds