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In organic chemistry, the Malaprade reaction or Malaprade oxidation is a glycol cleavage reaction in which a vicinal diol is oxidized by periodic acid or a periodate salt to give the corresponding carbonyl functional groups. [1] [2] The reaction was first reported by Léon Malaprade in 1928. [3] [4] Amino alcohols are also cleaved. [5]
Ethylene glycol has relatively high mammalian toxicity when ingested, roughly on par with methanol, with an oral LD Lo = 786 mg/kg for humans. [30] The major danger is due to its sweet taste, which can attract children and animals. Upon ingestion, ethylene glycol is oxidized to glycolic acid, which is, in turn, oxidized to oxalic acid, which is ...
The Criegee oxidation is a glycol cleavage reaction in which vicinal diols are oxidized to form ketones and aldehydes using lead tetraacetate. It is analogous to the use of periodate (Malaprade reaction) but uses a milder oxidant. This oxidation was discovered by Rudolf Criegee and coworkers and first reported in 1931 using ethylene glycol as ...
Examples include ethane-1,2-diol or ethylene glycol HO−(CH 2) 2 −OH, a common ingredient of antifreeze products. Another example is propane-1,2-diol, or alpha propylene glycol, HO−CH 2 −CH(OH)−CH 3, used in the food and medicine industry, as well as a relatively non-poisonous antifreeze product.
The carbon–carbon bond in a vicinal diol (glycol) is cleaved and instead the two oxygen atoms become double-bonded to their respective carbon atoms. Depending on the substitution pattern in the diol, these carbonyls will be ketones and/or aldehydes. [1] Glycol cleavage is an important for determining the structures of sugars.
The toxicity of ethylene glycol comes from its metabolism to glycolic acid and oxalic acid. The goal of pharmacotherapy is to prevent the formation of these metabolites. Ethanol acts by competing with ethylene glycol for alcohol dehydrogenase (ADH), the first enzyme in the degradation pathway.
One of them, Charles Friedel, believed the reaction product to be the epoxide tetramethylethylene oxide [7] in analogy with reactions of ethylene glycol. Finally Butlerov in 1873 came up with the correct structures after he independently synthesised the compound trimethylacetic (pivalic) acid which Friedel had obtained earlier by oxidizing with ...
In its use as a qualitative test for aldehydes, the unknown sample is added to the decolorized Schiff reagent; when aldehyde is present a characteristic magenta color develops. Schiff-type reagents are used for various biological tissue staining methods, e.g. Feulgen stain and periodic acid-Schiff stain.