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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 In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
Ti4(OCH2CH3)16. It is a commercially available colorless liquid that is soluble in organic solvents but hydrolyzes readily. Its structure is more complex than suggested by its empirical formula. Like other alkoxides of titanium(IV) and zirconium(IV), it finds used in
organic synthesis Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...
and
materials science Materials science is an interdisciplinary field of researching and discovering materials. Materials engineering is an engineering field of finding uses for materials in other fields and industries. The intellectual origins of materials sci ...
.


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 atomic nucleus, nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near and far field, near field) and respond by producing ...
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 C2h.


Related compounds


Titanium methoxide

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


Titanium isopropoxide

With bulky alkyl 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

Hydrolysis of Ti alkoxides can be used to deposit TiO2: :Ti(OEt)4 + 2 H2O → TiO2 + 4 EtOH The course of the hydrolysis 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. This is the sol-gel process. Intermediates in the hydrolysis have been crystallized. They feature interior oxides in addition to the ethoxide on the exterior of the clusters. The high reactivity of titanium ethoxide toward water is exploited in its use in
condensation reaction In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a ...
s.


References

{{Titanium compounds Ethoxides Titanium(IV) compounds