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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.
Pyridine can be prepared by dealkylation of alkylated pyridines, which are obtained as byproducts in the syntheses of other pyridines. The oxidative dealkylation is carried out either using air over vanadium(V) oxide catalyst, [67] by vapor-dealkylation on nickel-based catalyst, [68] [69] or hydrodealkylation with a silver- or platinum-based ...
of formation, Δ f H o liquid: 100 kJ/mol Standard molar entropy, S o liquid: 177 J/(mol K) Enthalpy of combustion, Δ c H o –2782 kJ/mol Heat capacity, c p: 132.72 J/(mol K) Gas properties Std enthalpy change of formation, Δ f H o gas: 140 kJ/mol at 25 °C Standard molar entropy, S o gas? J/(mol K) at 25 °C Heat capacity, c p [3] 157.8 J ...
The first reaction is the formation of the N-2,4-dinitrophenyl-pyridinium salt (2). This salt is typically isolated and purified by recrystallization. The formation of the DNP-pyridinium salt. Upon heating a primary amine with the N-2,4-dinitrophenyl-pyridinium salt (2), the addition of the amine leads to the opening of the pyridinium ring.
The amide group can be involved in hydrogen bonding to other nitrogen- and oxygen-containing species.. The predominant solid state form is 2-pyridone. This has been confirmed by X-ray crystallography which shows that the hydrogen in solid state is closer to the nitrogen than to the oxygen (because of the low electron density at the hydrogen the exact positioning is difficult), and IR ...
The Boger pyridine synthesis is a cycloaddition approach to the formation of pyridines named after its inventor Dale L. Boger, who first reported it in 1981. [1] The reaction is a form of inverse-electron demand Diels-Alder reaction in which an enamine reacts with a 1,2,4- triazine to form the pyridine nucleus.
In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group (−NO 2) into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters ( −ONO 2 ) between alcohols and nitric acid (as occurs in the synthesis of nitroglycerin ).
Compared to benzene, the rate of electrophilic substitution on pyridine is much slower, due to the higher electronegativity of the nitrogen atom. Additionally, the nitrogen in pyridine easily gets a positive charge either by protonation (from nitration or sulfonation) or Lewis acids (such as AlCl 3) used to catalyze the reaction. This makes the ...