Tetra-n-butylammonium chromate

It has been claimed that chromium trioxide reacts with tetra-n-butylammonium chloride in water to produce tetra-n-butylammonium chromate, n-Bu4N+HCr04- [7], whereas benzyltriethylammonium dichromate is obtained from the closely analogous reaction of benzyltriethylammonium chloride with chromium trioxide in dilute hydrochloric acid [8]. 

Tetra-n-butylammonium acetate, 442 Tetra-n-butylammonium chromate, 443 Tetra-n-butylammonium di-f-butyl phosphate, 443... 

Tetra-n-butylammonium chromate, HCr04"N(C4H9-n)4. Mol. wt. 359.47, yellow-orange solid, soluble in chloroform. 

Another chromium reagent for the oxidation of secondary alcohols to ketones is tetra-n-butylammonium chromate which is readily prepared by the addition of tetrabutylammonium chloride to an aqueous solution of CrOa. This reagent is very soluble in chloroform and, although only a limited number of substrates were studied, yields were good (80%) using only a small excess of oxidant. 

Chromium trioxide is also solublized in dichloromethane in the form of complex chromates Q+[X(CrO,) ] by the addition of an appropriate tetra-n-butylammonium salt [9-14],... 

The tetraalkylammonium chromates prepared by Gelbard and coworkers a q)eared to be equally effective for all types of alcohols, but under the conditions of Santaniello et al., tetra-n-butylammonium chlorochromate was found to be a selective benzylic and allylic oxidant. It also efficiently converts aliphatic and aromatic thiols to disulfides. Trimethylammonium chlorochromate has also bera reported for the oxidation of allylic alcohols in DMF. ... 

---