Di-tert-butyl chromate


Di-tert-butyl chromate is an alkoxide with the formula CrO22. 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. This ester is stable because tertiary alcohols such as tert-butyl alcohol lack alpha hydrogens, stopping the E2 elimination required for the oxidation of chromate esters. This complex and its analogues have tetrahedral geometry at chromium, as established by X-ray crystallography of its analogues.

Preparation

It can be prepared from tert-butyl alcohol and chromium trioxide or chromyl chloride.

Applications

It is used as a precursor to chromium-based catalysts, such as the Phillips catalyst, which are employed for the polymerization of ethylene.

Safety

Like other forms of hexavalent chromium, di-tert-butyl chromate is classified as a potential carcinogen by the United States National Institute for Occupational Safety and Health.