Chromic anhydride, oxidation with

In the presence of acids, linalool isomerizes readily to geraniol, nerol, and a-terpineol. It is oxidized to citral by chromic acid. Oxidation with peracetic acid yields linalool oxides, which occur in small amounts in essential oils and are also used in perfumery. Hydrogenation of linalool gives tetrahydrolinalool, a stable fragrance material. Its odor is not as strong as, but fresher than, that of linalool. Linalool can be converted into linalyl acetate by reaction with ketene or an excess of boiling acetic anhydride [34]. 

Oxidations with chromium trioxide (chromic oxide or chromic anhydride) and with chromic acid are carried out in different solvents, usually by adding solutions of chromic oxide or chromic acid to the solutions of the alcohols. When chromium trioxide dissolved in 80% acetic acid is added to a stirred solution of cis-2-phenylcyclohexanol in acetic acid at 50 °C and the mixture is allowed to stand at room temperature for 1 day, an 80% yield of 2-phenylcyclohexanone is obtained [576], Other solvents used are dimethylformamide [542], hexamethylphosphoric triamide (HMPA) [543], acetone [578, 5 i], ether [55 ], dichloromethane [555, 617], and benzene [571] (equation 249). 

Reaction of chromic anhydride (CrOg) with t-butanol yields t-butyl hydrogen chromate, a powerful oxidant suitable for allylic oxidation of electron-deficient alkenes. Oxidations using t-BuOCr03H in CCI4 are highly exothermic and should be performed with caution. 

By oxidation of the methyl derivative of an aromatic hydrocarbon with a solution of chromic anhydride in acetic anhydride and acetic acid. The aldehyde formed is immediately converted into the (/m-diacetate, which is stable to oxidation. The diacetate is collected and hydrolysed with sulphuric acid, for example ... 

Chromium trioxide (chromic anhydride) [1333-82-0] M 100.0, m 197°, dec at 250° to Cr203, d 2.70 (pK 0.74, pK 6.49, for H2Cr04, chromic acid). Red crystals from water (0.5mL/g) between 100° and -5°, or from water/conc HNO3 (1 5). It separates when potassium or sodium dichromate are dissolved in cone H2SO4. Dried in a vacuum desiccator over NaOH pellets hygroscopic, powerful oxidant, can ignite with organic compounds. It is a skin and pulmonary IRRITANT. 

Cholestanone has been prepared by the oxidation of dihydro-eholesterol with chromic anhydride in acetic acid solution.1 The yield is sometimes diminished as a result of the partial acetylation of the sterol. 

Chromium oxides with a minimal sulfur content are preferred for metallurgical applications. These are obtained by reacting sodium dichromate with ammonium chloride or sulfate in a deficiency of 10 mol% [3.51]. Chromium (III) oxides with a low sulfur content can also be obtained by thermal aftertreatment [3.52], Thermal decomposition of chromic acid anhydride (Cr03) yields high-purity chromium(III) oxide [3.53],... 

Other tetrasnhstituted olefins (Eq. 115) have recently boon reported18 4-1844 to yield the corresponding epoxides on oxidation with chromic noid in glacial acetic add, Mosher and co-workers also noted in addition the formation of significant proportions of cyclic carbonate when all traces of winter were excluded from tfio reaction medium by addition of acetic anhydride.1944... 

Camphoric yields eampheite oxide on oxidation with chromic oxide in acetic anhydride at — (Eq. 112), but 1-mcthyl-a-... 

JONES OXIDATION. The oxidation of primary and secondary alcohols to acids and ketones by the addition of the calculate amount of chromic anhydride in dilute sulfuric acid to a solution of the alcohol in acetone. This procedure dues not attack triple bonds or shift douhle bonds into conjugation with the ketone formed in the oxidation. 

Azoxybenzene has been prepared by reduction of nitrobenzene with alcoholic potassium hydroxide,1 with sodium amalgam,2 with hydrogen in the presence of lead oxide,3 with methyl alcohol and sodium hydroxide,4 with sodium methylate and methyl alcohol,5 and by electrolytic reduction 6 by oxidation of azobenzene with chromic anhydride 7 by treatment of /9-phenylhydroxylamine with alkaline potassium permanganate,8 with nitrobenzene,9 with mineral adds,10 and with mercury acetamide,11 and by oxidation of aniline with hydrogen peroxide,12 and with acid permanganate solution in the presence of formaldehyde.13 The procedure described above is a slight modification of one described in the literature.14... 

The oxidation of 10 with chromic anhydride in aqueous acetic acid leads to anthrone 218 and to anthraquinone 219 with excess oxidant. According to the authors opinion (54JOC1533), the oxidation process was supposed to include the primary formation of diketone 9 it was this compound, but not the initial salt 10, which was oxidized to anthrone 218. 

---