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  2. Pyridine - Wikipedia

    en.wikipedia.org/wiki/Pyridine

    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.

  3. Water-reactive substances - Wikipedia

    en.wikipedia.org/wiki/Water-reactive_substances

    Water-reactive substances [1] are those that spontaneously undergo a chemical reaction with water, often noted as generating flammable gas. [2] Some are highly reducing in nature. [ 3 ] Notable examples include alkali metals , lithium through caesium , and alkaline earth metals , magnesium through barium .

  4. Pyridine-N-oxide - Wikipedia

    en.wikipedia.org/wiki/Pyridine-N-oxide

    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]

  5. Degassing - Wikipedia

    en.wikipedia.org/wiki/Degassing

    The solubility of gas obeys Henry's law, that is, the amount of a dissolved gas in a liquid is proportional to its partial pressure. Therefore, placing a solution under reduced pressure makes the dissolved gas less soluble. Sonication and stirring under reduced pressure can usually enhance the efficiency.

  6. Knoevenagel condensation - Wikipedia

    en.wikipedia.org/wiki/Knoevenagel_condensation

    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 .

  7. Acid–base extraction - Wikipedia

    en.wikipedia.org/wiki/Acid–base_extraction

    Acid–base extraction is a subclass of liquid–liquid extractions and involves the separation of chemical species from other acidic or basic compounds. [1] It is typically performed during the work-up step following a chemical synthesis to purify crude compounds [2] and results in the product being largely free of acidic or basic impurities.

  8. 4-Pyridone - Wikipedia

    en.wikipedia.org/wiki/4-Pyridone

    4-Pyridone exists a keto-enol tautomerism with its enol tautomer 4-hydroxypyridine. In solution, the keto tautomer is favoured, [4] and the enol tautomer only becomes important in very dilute solutions or solutions of non-polar solvents.

  9. Azeotropic distillation - Wikipedia

    en.wikipedia.org/wiki/Azeotropic_distillation

    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 ...