Titanium ethoxide is a

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 element ...

with the formula Ti₄(OCH₂CH₃)₁₆. It is a colorless liquid that is soluble in organic solvents but hydrolyzes readily. It is sold commercially as a colorless solution. Alkoxides of titanium(IV) and zirconium(IV) are used in organic synthesis and materials science. They adopt more complex structures than suggested by their empirical formulas.

Syntheses

Titanium ethoxide is prepared by treating titanium tetrachloride with ethanol in the presence of an amine: :TiCl₄ + 4 EtOH + 4 Et₃N → Ti(OEt)₄ + 4 Et₃NHCl The purity of titanium ethoxide is commonly assayed by proton

NMR Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field (in the near field) and respond by producing an electromagnetic signal with ...

spectroscopy. Ti(OEt)₄ 1H NMR (90 MHz, chloroform-d, ppm): 4.36 (quartet, 8H, CH₂), 1.27 (triplet, 12H, CH₃).

Structure

Both Ti(OEt)₄ exist mainly as tetramers with an octahedral coordination environment around the metal centers. There are two types of titanium centers, depending on the number of terminal vs bridging alkoxide ligands. Zr(OEt)₄ is structurally similar. The virtual symmetry of the M₄O₁₆ core structure for the tetramer structures of these compounds is C_2h.

Related compounds

Titanium methoxide

Like the ethoxide, titanium methoxide Ti(OMe)₄ exists as a tetramer with each of the Ti^IV metal centers having an octahedral coordination environment.

Titanium isopropoxide

With bulky alky groups, Ti(O^''i''Pr)₄ in contrast exist as a monomer with a tetrahedral environment around the Ti center. This lower degree of coordination to the metal center is attributed to the steric bulk of the ^''i''Pr groups versus the ''n''-alkyl groups, this serves to prevent bridging interactions between the metal centers.

Zirconium ethoxide

Zirconium ethoxide can be prepared in a manner similar but not identical to the titanium compound: :ZrCl₄ + 5 NaOEt + EtOH → NaH r(OEt)₆+ 4 NaCl :NaH r(OEt)₆+ HCl → Zr(OEt)₄ + NaCl + 2 EtOH A more common synthesis for zirconium ethoxide is to treat zirconium tetrachloride with the desired alcohol and ammonia: :ZrCl₄ + 4 ROH + 4 NH₃ → Zr(OR)₄ + 4 NH₄Cl Zirconium ethoxide can also be prepared with zirconocene dichloride: :Cp₂ZrCl₂ + 4 EtOH + 2 Et₃N → 2 CpH + 2 Et₃NHCl + Zr(OEt)₄

Zirconium propoxide

Zr(O^''n''Pr)₄ also adopts the titanium ethoxide structure.

Reactions

Both Ti and Zr alkoxides can be used to deposit microstructured films of TiO₂ or ZrO₂: :M(OEt)₄ + 2 H₂O → MO₂ + 4 EtOH These films form via a hydrolysis of the alkoxide. The resulting oxides are chemically resilient. The structure of the metal oxide films grown in this matter is affected by the presence of base or acid catalysts for the hydrolysis. Generally acid-catalysis yields a sol where the polymer chains are randomly oriented and linear. In the base-mediated case bushy clusters or crosslinked networks are produced, these structures can trap solvent and reaction byproducts and form a gel coating. Ti^IV and Zr^IV alkoxides are also potential starting materials for

Ziegler–Natta catalyst A Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, is a catalyst used in the synthesis of polymers of 1-alkenes ( alpha-olefins). Two broad classes of Ziegler–Natta catalysts are employed, distinguished by their solubility: * ...

s used in

alkene polymerization In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...

. Intermediates in the hydrolysis have been crystallized. They feature interior oxides in addition to the ethoxide on the exterior of the clusters.

References

{{Titanium compounds Ethoxides Titanium(IV) compounds