Di-''tert''-butyl chromate is an
alkoxide
In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organic substituent. Alkoxides are strong bases and, whe ...
with the formula CrO
2(OC(CH
3)
3)
2. It is prepared by treatment of ''t''-butanol with chromic anhydride. It forms red crystals at temperatures below –5 °C, above which it melts to give a red oil. The complex, which is diamagnetic, is of fundamental interest as a model for the intermediates in oxidations of alcohols by chromium(VI). This complex is stable because as a t-butyl groups lack beta-hydrogens. This complex and its analogues have tetrahedral geometry at chromium, as established by
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
of its analogues.
Applications
It is used as a precursor to chromium-based catalysts, such as the
Phillips catalyst
The Phillips catalyst, or the Phillips supported chromium catalyst, is the catalyst used to produce approximately half of the world's polyethylene. A heterogeneous catalyst, it consists of a chromium oxide supported on silica gel. Polyethylene, ...
, which are employed for the polymerization of
ethylene
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds).
Ethylene i ...
.
Safety
Like other forms of
hexavalent chromium
Hexavalent chromium (chromium(VI), Cr(VI), chromium 6) is chromium in any chemical compound that contains the element in the +6 oxidation state (thus hexavalent). Virtually all chromium ore is processed via hexavalent chromium, specifically the ...
, di-''tert''-butyl chromate is classified as a potential carcinogen by the United States
National Institute for Occupational Safety and Health
The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...
.
References
{{DEFAULTSORT:Butyl chromate, tert-
Chromates
Tert-butyl compounds