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The Kröhnke pyridine synthesis provides a fairly general method for generating substituted pyridines using pyridine itself as a reagent which does not become incorporated into the final product. The reaction of pyridine with bromomethyl ketones gives the related pyridinium salt, wherein the methylene group is highly acidic.
This page contains tables of azeotrope data for various binary and ternary mixtures of solvents. The data include the composition of a mixture by weight (in binary azeotropes, when only one fraction is given, it is the fraction of the second component), the boiling point (b.p.) of a component, the boiling point of a mixture, and the specific gravity of the mixture.
Pyridine-N-oxide is the heterocyclic compound with the formula C 5 H 5 NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis. [1]
For instance, in a distillation of ethanol and water, water will boil out of the remaining ethanol, rather than the ethanol out of the water as at lower concentrations. Overall the pressure-swing distillation is a very robust and not so highly sophisticated method compared to multi component distillation or membrane processes, but the energy ...
Heterocycles are often activated towards cation–π binding when the lone pair on the heteroatom is in incorporated into the aromatic system (e.g. indole, pyrrole). Conversely, when the lone pair does not contribute to aromaticity (e.g. pyridine), the electronegativity of the heteroatom wins out and weakens the cation–π binding ability.
Acrolein and malonic acid react in pyridine to give trans-2,4-pentadienoic acid with the loss of carbon dioxide. The Doebner modification of the Knoevenagel condensation entails the use of pyridine as a solvent with at least one of the withdrawing groups on the nucleophile is a carboxylic acid , for example, with malonic acid .
The Sarett oxidation is an organic reaction that oxidizes primary and secondary alcohols to aldehydes and ketones, respectively, using chromium trioxide and pyridine.Unlike the similar Jones oxidation, the Sarett oxidation will not further oxidize primary alcohols to their carboxylic acid form, neither will it affect carbon-carbon double bonds. [1]
Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a biological membrane that forms the boundary between an organism and its extracellular environment.