Vanadium oxytrichloride

Jump to: navigation, search
Vanadium oxytrichloride
Vanadium oxytrichloride fuming in air Ball-and-stick model of vanadyl chloride
General
Systematic name Vanadium(V) oxide trichloride
Other names Vanadium oxytrichloride
Vanadyl chloride
Vanadyl trichloride
Molecular formula VOCl3
SMILES VOClClCl
Molar mass 173.30 g/mol
Appearance Yellow to brown liquid
CAS number [7727-18-6]
Properties
Density and phase 1.84 g/cm3, liquid
Solubility in water Decomposes
Other solvents chlorinated solvents
Melting point -76.5 °C
Boiling point 126–127 °C (400 K)
Viscosity ? cP at ? °C
Structure
Molecular shape Tetrahedral
Dipole moment ? D
Hazards
MSDS External MSDS
Main hazards Toxic, hydrolysis to HCl
NFPA 704
NFPA 704.svg
1
3
3
 
R/S statement R: R14 R25 R34
S: S26 S27 S28
S36/37/39 S45
RTECS number YW2975000
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related vanadium
compounds
Vanadium(V) oxide
Vanadium tetrachloride
Vanadium oxytrifluoride
Related compounds Phosphorus oxytrichloride
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Vanadium oxytrichloride is VOCl3. It is a distillable liquid, which hydrolyzes readily in air (see picture). VOCl3 is a vanadium(V) compound and as such diamagnetic. It is tetrahedral with O-V-Cl bond angles of 111° and Cl-V-Cl bond angles of 108°. The V-O and V-Cl bond lengths are 1.57 and 2.14 Å, respectively.

Properties

VOCl3 is highly reactive toward water and evolves Cl2 upon standing. Although VOCl3 reacts with hydroxylic solvents (see below), it is soluble in hydrocarbons such as benzene, CH2Cl2, and hexane.

In many aspects, the chemical properties of VOCl3 and POCl3 are similarly shaped molecular compounds. One distinction is that VOCl3 is a strong oxidizing agent, whereas the phosphorus compound is not.

Preparation

VOCl3 is synthesized by the chlorination of V2O5. The reaction proceeds at ca. 600 °C

3 Cl2 + V2O5 → 2 VOCl3 + 1.5 O2

When the V2O5 is used as an intimate mixture with carbon, the synthesis proceeds at 200-400 °C; in this case the carbon serves as a deoxygenation agent akin to its use in the Kroll process for the manufacturing of TiCl4 from TiO2.

Vanadium(III) oxide can also be used as a precursor:

3 Cl2 + V2O3 → 2 VOCl3 + 0.5 O2

A more typical laboratory synthesis entails chlorination of V2O5 using SOCl2.

V2O5 + 3 SOCl2 → 2 VOCl3 + 3 SO2

Reactions

Hydrolysis and alcoholysis

Vanadium oxytrichloride quickly hydrolyzes resulting in vanadium pentoxide and hydrochloric acid. In the picture, orange V2O5 can be seen forming on the walls of the beaker. An intermediate in this process is VO2Cl:

2 VOCl3 + 3 H2O → V2O5 + 6 HCl

VOCl3 react with alcohols especially in the presence of a proton-acceptor (e.g. Et3N) to give esters

VOCl3 + 3 ROH → VO(OR)3 + 3 HCl (R = Me, Ph, etc.)

Interconversions to other V-O-Cl compounds

VOCl3 is also used in the synthesis of VOCl2.

V2O5 + 3 VCl3 + VOCl3 → 6 VOCl2

Dioxovanadium monochloride can be prepared by an unusual reaction involving Cl2O.

VOCl3 + Cl2O → VO2Cl + 2 Cl2

At >180 °C, VO2Cl decomposes to V2O5 and VOCl3. Similarly, VOCl2 also decomposes to give VOCl3, together with VOCl.

Adduct formation

VOCl3 is strongly Lewis acidic, as demonstrated by its tendency to form adducts with various bases such as MeCN and amines. In forming the adducts, vanadium changes from four-coordinate tetrahedral geometry to six-coordinate octahedral geometry:

VOCl3 + 2 H2NEt → VOCl3(H2NEt)2

kiss my ass

VOCl3 in alkene polymerization

VOCl3 is used as a catalyst or precatalytst in production of ethylene-propylene rubbers (EPDM).

References

  • A. Earnshaw, N. Greenwood (1997). The Chemistry of the Elements - Second Edition. Unknown parameter |Page= ignored (|page= suggested) (help)
  • M. O'Brien, B. Vanasse (2001). Encyclopedia of Reagents for Organic Synthesis.
  • A. Holleman, E. Wiberg (2001). Inorganic Chemistry.
  • S. Tyree (1967). Inorganic Syntheses Volume IX. p. 80.
  • H. Oppermann, "Gleichgewichte mit VOCl3, VO2Cl, VOCl2" Zeitschrift für Anorganische und Allgemeine Chemie, vol. 331. 113-126 (1967)

External links



Linked-in.jpg