Chromic add

ChromsMure, /. chromic acid, -anhydrid, n. chromic anhydride, chromium(VI) oxide, emisch, n. chromic acid mixture. -Ibsung. /. chromic acid solution, -salz, n. salt of chromic add, chromate. 

Oxidation, of Grignard reagents with peresters, 41, 91 43, 55 of 2-hydroxy-3-methylbenzoic acid to 2-hydroxyisophthalic acid by lead dioxide, 40, 48 of indene, 41, 53 44, 63 of indolepyruvic add, 44, 66 of methyl disulfide to methanesul finy 1 chloride by chlorine, 40, 62 of 2-exo-norbomyl formate by chromic add, 42, 79... 

In the past, chromic add solutions have been used for cleaning. These solutions consist of concentrated sulfuric add in which solid potassium dichromate has been dissolved. Because of safety concerns and concerns with chromium contamination in the environment, chromic add has been essentially eliminated from use. 

An additional 2.2 g. (4%) of cyclooctanone may be obtained by addition of 250 ml. of water to the green salts formed during the reaction (Note 10), extraction of the mixture with ether, distillation of the ether, and addition of 12 ml. of acetone. To the acetone solution there is added sufficient chromic add oxidizing reagent to permit the orange color of the reagent to persist (Note 11), and the mixtiure is processed as above. 

Ethynyl Ketones by Oxidation of the Corresponding Ethynyl Carbinols with Chromic Add... 

Mmatim,—1. By the oxidation of the normal alcohols of the methyl series, as in the conversion of alcohol into acetic add by heating it with a solution of chromic add... 

CHROMIC ANHYDRIDE Chromic Oxide, Chromic Trioxide, Chromic Add Oxidizing Material, 1 (S) 3 (1 1 ... 

In the field of steroids, attention may be directed to a eignifican-. anomaly recently clarified by Fieser and Goto. 3 Treatment of bhoJeetenyl acetate vith chromic add in aqueous acetic acid at 25 ... 

Thomer and Zinche1714 1710 utilized hot chromic acid to carry out oxidative de v ge of tetraphenylethylene oxide and related subetanees (Eq. 426). In a similar manner R be and Hallensieben1484 oxidized atilbcne oxide to benzoic add with chromic add (Eq. 429). 

The allylic oxidation with derivatives of chromic add (K.B. Wiberg, 1965 H.G. Bosche, 1975), e.g. di-t-butyl chromate (K. Fujita, 1961), CrOj/pyridine (W.G. Dauben, 1969), or KjCr04 (C.Y. Cuilleron, 1970), gives similar products in occasionally very high yields. 

Cr03 + H2O —> H2C1O4 chromic add 2Cr03 + H2O —> H2O2O7 dichromic acid... 

Purification is effected mainly by the methods already described. Crude phosphorus may be melted under dilute solutions of chromic add, nitric acid or chlorine. Arsenic may be removed by distilling in a current of steam and carbon dioxide, and condensing under water. Phosphorus can be granulated if desired by melting under water and shaking until cold. 

The method given in these directions 6 may be modified by using potassium hypochlorite 7 or chromic add 8 as the oxidizing agent. 

Aldol cyclization. Although the keto aldehyde 1 is resistant to aldol cyclization under normal, alkaline conditions, this reaction can be accomplished by a method originally developed by Raphael et Reduction of the enol lactone (2), derived from 1, with DIBAH produces a bridged ketol, which is oxidized to 3 with chromic add. This diketone was employed as an intermediate in a synthesis of the sesquiterpene gymnomitrol (4). 

Chromium trioxide [chromium(VI) oxide, chromic add, or chromic anhydride], Cr03 (dark red crystals, mp 195 °C), is one of the most powerful and universal oxidants. It is applied in solutions in acetic acid, dilute sulfuric acid, a mixture of acetic acid and dilute sulfuric acid, dilute sulfuric acid and acetone (Jones reagent), acetic anhydride and acetic acid (Fieser reagent) [535], water, water and ether [536,537,535], dichloromethane [539],... 

Alkylnaphthalenes are converted into alkyl-1,4-naphthoquinones with peroxyacetic acid [139] or chromic add [557]. Under the conditions of these reactions (equation 151), the alkyl groups resist oxidation to carboxyl groups. 

Chromic add, HjCrO. See also Chromic anhydride in aqueous acetic acid. 

In the air, and on treatment with oxidising agents like nitric acid, chromic add, etc., the thiophenols are oxidised to disulphides ... 

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