Di-tert-butyl chromate

Di-tert-butyl chromate is an alkoxide with the formula CrO₂(OC(CH₃)₃)₂. It forms red crystals at temperatures below −5 °C, above which it melts to give a red oil.^[3][4] 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 of its analogues.^[5][6]

tert-Butyl chromate

Names
IUPAC name tert-Butyl chromate
Other names Di-tert-butyl ester of chromic acid; Bis(tert-butyl)chromate
Identifiers
CAS Number	1189-85-1
3D model (JSmol)	Interactive image
ChemSpider	11649895
PubChem CID	102059956 wrong formula
RTECS number	GB2900000
CompTox Dashboard (EPA)	DTXSID401015717
InChI InChI=1S/2C4H9O.Cr.2O/c2*1-4(2,3)5;;;/h2*1-3H3;;;/q2*-1;+2;; Key: PNWJTIFZRHJYLK-UHFFFAOYSA-N InChI=1/2C4H9O.Cr.2O/c2*1-4(2,3)5;;;/h2*1-3H3;;;/q2*-1;+2;;/rC8H18CrO4/c1-7(2,3)12-9(10,11)13-8(4,5)6/h1-6H3 Key: PNWJTIFZRHJYLK-PZTLRDNSAU
SMILES O([Cr](OC(C)(C)C)(=O)=O)C(C)(C)C
Properties
Chemical formula	[(CH3)3CO]2CrO2
Molar mass	230.3 g/mol[1]
Appearance	red oil
Melting point	−2.8 °C (27.0 °F; 270.3 K)[2]
Solubility in water	Miscible[2]
Hazards
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.005 mg CrO3/m3 [skin][1]
REL (Recommended)	Ca TWA 0.001 mg Cr(VI)/m3[1]
IDLH (Immediate danger)	Ca [15 mg/m3 {as Cr(VI)}][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

It can be prepared from Tert-Butyl alcohol and Chromium Trioxide or Chromyl Chloride^[3]

Applications

It is used as a precursor to chromium-based catalysts, such as the Phillips catalyst, which are employed for the polymerization of ethylene.^[7]

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.^[1][2]