Jones reagent sulfuric acid

Jones Oxidation. Dissolve 5 mg of the unknown in 0.5 mL of pure acetone in a test tube and add to this solution 1 small drop of Jones reagent (chromic acid in sulfuric acid). A positive test is formation of a green color within 5 s upon addition of the orange-yellow reagent to a primary or secondary alcohol. Aldehydes also give a positive test, but tertiary alcohols do not. 

When a solution of chromic and sulfuric acids in water is added at 0-20° to an alcohol or formate dissolved in acetone, a rapid oxidation takes place with the separation of the green chromium III reduction product as a separate layer. This system is commonly known as Jones reagent. The rate of oxidation is so fast that it is often possible to run the reaction as a titration to an... 

Jones reagent is prepared by dissolving chromium oxide (C1O3) (23.5 g) in coned sulfuric acid (21 mL) with cooling and then diluting with distilled water to give a total volume of 175 mL.4... 

Jones reagent was prepared by the method in Fieser and Fieser Dissolve 13.36 g of chromium trioxide in 11.5 nt of coned sulfuric acid, and carefully dilute this cooled solution (0 C) with water to 50 ml. 

Aromatization of a tetrahydroquinolizone (5) by means of acetic anhydride and sulfuric acid or acetic anhydride alone leads to the formation of a variety of mono- or di-substituted quinolizinium compounds. Glover and Jones 8 achieved the synthesis of a number of these derivatives starting from 2-cyanopyridine and condensing it with appropriate Grignard reagents followed by cyclization and aromatization as outlined in Eq. (2). An identical method was simultaneously worked out by Nesmeyanov and Rybinskaya9 for the specific synthesis of 2-substituted quinolizinium compounds. This... 

Bottles of HC104 should not be stored on wooden shelves, because acid spilled on wood can form explosive cellulose perchlorate esters. Perchloric acid also should not be stored near organic reagents or reducing agents. A reviewer of this book once wrote, I have seen someone substitute perchloric acid for sulfuric acid in a Jones reductor experiment with spectacular results—no explosion but the tube melted ... 

Oxidations of alcohols with water-free Cr(VI) reagents, such as the ones in rows 3-5 in Table 17.5, always result in the formation of carbonyl compounds. In particular, a carbonyl compound is obtained even if it is an aldehyde and therefore in principle could be oxidized to give the carboxylic acid. On the other hand, aldehydes are oxidized further (rows 1 and 3 in Table 17.5) if one uses water-containing Cr(VI) reagents (e. g., oxidations with K2Cr207 in sulfuric acid) or the Jones reagent (unless the latter is used under really mild conditions). Fig-... 

Oxidation of alcohols is normally carried out with Cr(VI) reagents (Chapter 24) but these, like the Jones reagent (Na2Cr2C>7 in sulfuric acid), are usually acidic. Some pyridine complexes of Cr(Vl) compounds solve this problem by having the pyridinium ion (p Ta 5) as the only acid. The two most famous are PDC (Pyridinium DiChromate) and PCC (Pyridinium Chloro-Chromate). Pyridine forms a complex with CrO but this is liable to burst into flames. Treatment with HC1 gives PCC, which is much less dangerous. PCC is particularly useful in the oxidation of primary alcohols to aldehydes as overoxidation is avoided in the only slightly acidic conditions (Chapter 24). 

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],... 

The main applications of oxidation with chromium trioxide are transformations of primary alcohols into aldehydes [184, 537, 538, 543, 570, 571, 572, 573] or, rarely, into carboxylic acids [184, 574], and of secondary alcohols into ketones [406, 536, 542, 543, 575, 576, 577, 578, 579, 580, 581, 582, 583, 584]. Jones reagent is especially successful for such oxidations. It is prepared by diluting with water a solution of 267 g of chromium trioxide in a mixture of 230 mL of concentrated sulfuric acid and 400 mL of water to 1 L to form an 8 N CrOj solution [565, 572, 579, 581, 585, 556]. Other oxidations with chromic oxide include the cleavage of carbon-carbon bonds to give carbonyl compounds or carboxylic acids [482, 566, 567, 569, 580, 587, 555], the conversion of sulfides into sulfoxides [541] and sulfones [559], and the transformation of alkyl silyl ethers into ketones or carboxylic acids [590]. 

A solution of chromium trioxide in dilute sulfuric acid used in aqueous acetone is called Jones reagent [572]. Other solvents of chromium trioxide are ether [535] and hexamethylphosphoric triamide (HMPA) [543. Oxidations are also carried out with chromium trioxide adsorbed on Celite (diatomaceous earth) [53S], silica gel [537], or an ion exchanger such as Amberlyst A26 (a macroreticular quaternary ammonium salt anion exchanger) [571, 617]. Such oxidations often take place at room temperature and can be used not only for saturated alcohols but also for unsaturated and aromatic alcohols (equations 208 and 209). 

Chromium trioxide (Cr03) in sulfuric acid (H2S04)(Jones reagent) v Hot basic permanganate followed by acidification... 

Ando s synthesis of hymenolin. xhis chromium trioxide/acetone/sulfuric acid reagent is often referred to as the Jones reagent, and oxidation of alcohols with this reagent is called Jones oxidation. Direct conversion of a primary alcohol to an acid is seen in the oxidation of 20 to 21, quantitatively, in Omura, Smith and coworker s synthesis of (+)-lactacystin.5 Jones oxidation is especially useful for molecules that contain alkenyl or alkynyl groups. 2 Oxidation of alcohols is usually faster in acetone than in acetic acid, and using a large excess of acetone protects the ketone product from further oxidation. - Many primary alcohols are oxidized... 

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