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Tollens' reagent (chemical formula ()) is a chemical reagent used to distinguish between aldehydes and ketones along with some alpha-hydroxy ketones which can tautomerize into aldehydes. The reagent consists of a solution of silver nitrate , ammonium hydroxide and some sodium hydroxide (to maintain a basic pH of the reagent solution).
The further reaction of the Schiff reagent with aldehydes is complex with several research groups reporting multiple reaction products with model compounds. In the currently accepted mechanism, the pararosaniline and bisulfite combine to yield the "decolorized" adduct with sulfonation at the central carbon as described and shown.
In organic chemistry, Fehling's solution is a chemical reagent used to differentiate between water-soluble carbohydrate and ketone (>C=O) functional groups, and as a test for reducing sugars and non-reducing sugars, supplementary to the Tollens' reagent test. The test was developed by German chemist Hermann von Fehling in 1849. [1]
α-hydroxy ketones give positive Tollens' and Fehling's test. Some acyloins rearrange with positions swapped under the influence of base in the Lobry–de Bruyn–van Ekenstein transformation; A similar reaction is the so-called Voigt amination [6] where an acyloin reacts with a primary amine and phosphorus pentoxide to an α-keto amine: [7]
Reducing form of glucose (the aldehyde group is on the far right) A reducing sugar is any sugar that is capable of acting as a reducing agent. [1] In an alkaline solution, a reducing sugar forms some aldehyde or ketone, which allows it to act as a reducing agent, for example in Benedict's reagent. In such a reaction, the sugar becomes a ...
This reagent converts aldehydes to carboxylic acids without attacking carbon–carbon double bonds. The name silver-mirror test arises because this reaction produces a precipitate of silver, whose presence can be used to test for the presence of an aldehyde. A further oxidation reaction involves Fehling's reagent as a test.
The Washington Post argued in a new editorial that the benefits of gender-transition treatments for minors like puberty blockers have not been scientifically proven. "Treatment results that look ...
Molisch test (using α-napthol) indicating a positive result (see purple ring). Molisch's test is a sensitive chemical test, named after Austrian botanist Hans Molisch, for the presence of carbohydrates, based on the dehydration of the carbohydrate by sulfuric acid or hydrochloric acid to produce an aldehyde, which condenses with two molecules of a phenol (usually α-naphthol, though other ...