Titanium butoxide

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Titanium butoxide
File:Structural formula of titanium tetrabutoxide.svg
gas phase structure
Names
IUPAC name
Titanium(IV) butoxide
Other names
Titanium(IV) butoxide, titanium n-butoxide, titanium tetrakis(butoxide), butyl titanate, tetrabutoxy titanium, titanium tetrabutoxide, tetrabutoxytitanium, tetrabutyltitanate, tetrabutyl orthotitanate, titanium tetrabutanolate,[1][2] TYZOR TBT
Identifiers
3D model (JSmol)
ChemSpider
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EC Number
  • 227-006-8
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UNII
UN number 2920
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  • InChI=1S/4C4H9O.Ti/c4*1-2-3-4-5;/h4*2-4H2,1H3;/q4*-1;+4
    Key: YHWCPXVTRSHPNY-UHFFFAOYSA-N
  • CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-].[Ti+4]
Properties
C16H36O4Ti
Molar mass 340.32164
Appearance COLORLESS TO LIGHT-YELLOW LIQUID
Odor weak alcohol-like[1]
Density 0.998 g/cm3[1]
Melting point −55[1] °C (−67 °F; 218 K)
Boiling point 312[1] °C (594 °F; 585 K)
decomposes[1]
Solubility most organic solvents except ketones[1]
1.486[1]
Thermochemistry
711 J/(mol·K)[2]
−1670 kJ/mol[2]
Hazards
Lethal dose or concentration (LD, LC):
3122 mg/kg (rat, oral) and 180 mg/kg (mouse, intravenal).[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Titanium butoxide is a metal alkoxide with the formula Ti(OBu)4 (Bu = –CH2CH2CH2CH3). It is a colorless odorless liquid although aged samples can appear yellowish. Owing to hydrolysis, samples have a weak alcohol-like odor. It is soluble in many organic solvents.[1][3] Decomposition in water is not hazardous, and therefore titanium butoxide is often used as a liquid source of titanium dioxide, which allows deposition of TiO2 coatings of various shapes and sizes down to the nanoscale.[4][5]

Titanium butoxide is often used to prepare titanium oxide materials and catalysts.[6][7][citation needed]

Structure and synthesis

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File:Titanium 4 Ethoxide WIKI.png
Structure of a typical titanium alkoxide, e.g. titanium ethoxide (organic substituents removed for clarity).

Like most titanium alkoxides (exception: titanium isopropoxide), Ti(OBu)4 is not a monomer but exists as a cluster (see titanium ethoxide). Nonetheless it is often depicted as a simple monomer.[citation needed]

It is produced by treating titanium tetrachloride with butanol:

TiCl4 + 4 HOBu → Ti(OBu)4 + 4 HCl

The reaction requires base to proceed to completion.[citation needed]

Reactions

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Like other titanium alkoxides, titanium butoxide exchanges alkoxide groups:

Ti(OBu)4 + HOR → Ti(OBu)3(OR) + HOBu
Ti(OBu)3(OR) + HOR → Ti(OBu)2(OR)2 + HOBu

etc. For this reason, titanium butoxide is not compatible with alcohol solvents.

Analogous to the alkoxide exchange, titanium butoxide hydrolyzes readily. The reaction details are complex, but the overall process can be summarized with this balanced equation.

Ti(OBu)4 + 2 H2O → TiO2 + 4 HOBu

Diverse oxo-alkoxo intermediates have been trapped and characterized.[8] Pyrolysis also affords the dioxide:

Ti(OBu)4 → TiO2 + 2 Bu2O

Titanium butoxide reacts with alkylcyclosiloxanes. With ocatamethylcyclotetrasiloxane it produces dibutoxydimethylsilane, 1,5-dibutoxyhexamethyltrisiloxane, 1,7-dibutoxyoctamethyltetrasiloxane, 1,3-dibutoxytetramethyldisiloxane and polymers. With hexamethylcyclotrisiloxane it also produces dibutoxydimethylsilane.[9]

File:Chiral TiO2 nanofibers 2.jpg
leftSEM (top) and TEM (bottom) images of chiral TiO2 nanofibers produced by depositing titanium butoxide on carbon nanofibers. Carbon was removed by heating in air.[4]

Safety

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LD50 is 3122 mg/kg (rat, oral) and 180 mg/kg (mouse, intravenal).[citation needed]

Titanium butoxide is a corrosive, flammable liquid which reacts violently with oxidizing materials. It is incompatible with sulfuric and nitric acids, inorganic hydroxides and peroxides, bases, amines, amides, isocyanates and boranes. It is irritating to skin and eyes, and causes nausea and vomiting if swallowed. LD50 is 3122 mg/kg (rat, oral) and 180 mg/kg (mouse, intravenal); flash point is 77 °C. When heated it emits irritating fumes, which form explosive mixtures with air at concentrations above 2 vol%.[citation needed]

References

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  1. ^ a b c d e f g h i j Butyl titanate. pubchem.ncbi.nlm.nih.gov
  2. ^ a b c Tetrabutyl titanate. nist.gov
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