Titanium isopropoxide

Titanium isopropoxide, also commonly referred to as titanium tetraisopropoxide or TTIP, is a chemical compound with the formula Ti{OCH(CH3)2}4. This alkoxide of titanium(IV) is used in organic synthesis and materials science. It is a diamagnetic tetrahedral molecule. Titanium isopropoxide is a component of the Sharpless epoxidation, a Nobel-Prize-winning method for the synthesis of chiral epoxides.[1][2]

This article is about the chemical compound. For the free trade agreement abbreviated as TTIP, see Transatlantic Trade and Investment Partnership.
Titanium isopropoxide
Names
IUPAC name
Titanium isopropoxide
Other names
Tetraisopropyl titanate
Titanium(IV) i-propoxide
Titanium tetraisopropoxide
Tetraisopropyl orthotitanate
Identifiers
3D model (JSmol)
ECHA InfoCard 100.008.100
UNII
Properties
C12H28O4Ti
Molar mass 284.219 g·mol−1
Appearance colorless to light-yellow liquid
Density 0.96 g/cm3
Melting point 17 °C (63 °F; 290 K) approximation
Boiling point 232 °C (450 °F; 505 K)
Reacts to form TiO2
Solubility soluble in ethanol, ether, benzene, chloroform
1.46
Hazards
Lethal dose or concentration (LD, LC):
7600 mg/kg (rat, oral)
Related compounds
Other cations
 Aluminium isopropoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

The structures of the titanium alkoxides are often complex. Crystalline titanium methoxide is tetrameric with the molecular formula Ti4(OCH3)16.[3] Alkoxides derived from bulkier alcohols such as isopropylalcohol aggregate less. Titanium isopropoxide is mainly a monomer in nonpolar solvents.[4]

Preparation

It is prepared by treating titanium tetrachloride with isopropanol. Hydrogen chloride is formed as a coproduct:[4]

TiCl4 + 4 (CH3)2CHOH → Ti{OCH(CH3)2}4 + 4 HCl

Properties

Titanium isopropoxide reacts with water to deposit titanium dioxide:[5]

Ti{OCH(CH3)2}4 + 2 H2O → TiO2 + 4 (CH3)2CHOH

This reaction is employed in the sol-gel synthesis of TiO2-based materials in the form of powders or thin films. Typically water is added in excess to a solution of the alkoxide in an alcohol. The composition, crystallinity and morphology of the inorganic product are determined by the presence of additives (e.g. acetic acid), the amount of water (hydrolysis ratio), and reaction conditions.[5]

The compound is also used as a catalyst in the preparation of certain cyclopropanes in the Kulinkovich reaction. Prochiral thioethers are oxidized enantioselectively using a catalyst derived from Ti(O-i-Pr)4.[6][7]

Naming

Titanium(IV) isopropoxide is a widely used item of commerce and has acquired many names in addition to those listed in the table. A sampling of the names include: titanium(IV) i-propoxide, isopropyl titanate, tetraisopropyl titanate, tetraisopropyl orthotitanate, titanium tetraisopropylate, orthotitanic acid tetraisopropyl ester, Isopropyl titanate(IV), titanic acid tetraisopropyl ester, isopropyltitanate, titanium(IV) isopropoxide, titanium tetraisopropoxide, iso-propyl titanate, titanium tetraisopropanolate, tetraisopropoxytitanium(IV), tetraisopropanolatotitanium, tetrakis(isopropoxy) titanium, tetrakis(isopropanolato) titanium, titanic acid isopropyl ester, titanic acid tetraisopropyl ester, titanium isopropoxide, titanium isopropylate, tetrakis(1-methylethoxy)titanium.

Applications

TTIP can be used as a precursor for ambient conditions vapour phase deposition such as infiltration into polymer thin films.[8]

References
  1. Katsuki, T.; K. Barry Sharpless (1980). "The first practical method for asymmetric epoxidation". J. Am. Chem. Soc. 102 (18): 5974. doi:10.1021/ja00538a077.
  2. Hill, J. G.; Sharpless, K. B.; Exon, C. M.; Regenye, R. (1985). "Enantioselective Epoxidation Of Allylic Alcohols: (2s,3s)-3-propyloxiranemethanol". Org. Synth. 63: 66. doi:10.15227/orgsyn.063.0066.CS1 maint: uses authors parameter (link)
  3. Wright, D. A.; Williams, D. A. (1968). "The Crystal and Molecular Structure of Titanium Tetramethoxide". Acta Crystallographica B. 24 (8): 1107–1114. doi:10.1107/S0567740868003766.
  4. Donald Charlton Bradley; Ram C. Mehrotra; Rothwell, Ian P.; Singh, A. (2001). Alkoxo and Aryloxo Derivatives of Metals. San Diego: Academic Press. ISBN 978-0-08-048832-5.
  5. Hanaor, Dorian A. H.; Chironi, Ilkay; Karatchevtseva, Inna; Triani, Gerry; Sorrell, Charles C. (2012). "Single and Mixed Phase TiO2 Powders Prepared by Excess Hydrolysis of Titanium Alkoxide". Advances in Applied Ceramics. 111 (3): 149–158. arXiv:1410.8255. doi:10.1179/1743676111Y.0000000059.
  6. Zhao, S. H.; Samuel, O.; Kagan, H. B. (1987). "Asymmetric Oxidation of Sulfides Mediated by Chiral Titanium Complexes: Mechanistic and Synthetic Aspects". Tetrahedron. 43 (21): 5135–5144. doi:10.1016/S0040-4020(01)87689-4.
  7. Zhao, S. H.; Samuel, O.; Kagan, H. B. (1990). "Enantioelective Oxidation of a Sulfide: (S)-(−)-Methyl p-Tolyl Sulfoxide". Organic Syntheses. 68: 49. doi:10.15227/orgsyn.068.0049.; Collective Volume, 8, p. 464
  8. Giraud, Elsa C.; Mokarian-Tabari, Parvaneh; Toolan, Daniel T. W.; Arnold, Thomas; Smith, Andrew J.; Howse, Jonathan R.; Topham, Paul D.; Morris, Michael A. (2018-07-27). "Highly Ordered Titanium Dioxide Nanostructures via a Simple One-Step Vapor-Inclusion Method in Block Copolymer Films" (PDF). ACS Applied Nano Materials. 1 (7): 3426–3434. doi:10.1021/acsanm.8b00632.
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