enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Protonation - Wikipedia

    en.wikipedia.org/wiki/Protonation

    In chemistry, protonation (or hydronation) is the adding of a proton (or hydron, or hydrogen cation), usually denoted by H +, to an atom, molecule, or ion, forming a conjugate acid. [1] The complementary process, when a proton is removed from a Brønsted–Lowry acid , is deprotonation .)

  3. Oxonium ion - Wikipedia

    en.wikipedia.org/wiki/Oxonium_ion

    Extreme acidity, heat, and dehydrating conditions are usually required. Other hydrocarbon oxonium ions are formed by protonation or alkylation of alcohols or ethers (R−C− + −R 1 R 2). Secondary oxonium ions have the formula R 2 OH +, an example being protonated ethers. Tertiary oxonium ions have the formula R 3 O +, an example being ...

  4. Hydronium - Wikipedia

    en.wikipedia.org/wiki/Hydronium

    In chemistry, hydronium (hydroxonium in traditional British English) is the cation [H 3 O] +, also written as H 3 O +, the type of oxonium ion produced by protonation of water.It is often viewed as the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton (a positive hydrogen ion, H +) to the surrounding water molecules (H 2 O).

  5. Ortho effect - Wikipedia

    en.wikipedia.org/wiki/Ortho_effect

    The protonation of substituted aniline is inhibited by steric hindrance. When protonated, the nitrogen in the amino group changes its orbital hybridization from sp 2 to sp 3 , becoming non-planar. This leads to steric hindrance between the ortho-substituted group and the hydrogen atom of the amino group, reducing the stability of the conjugate ...

  6. Wittig reagents - Wikipedia

    en.wikipedia.org/wiki/Wittig_reagents

    The alkylphosphonium salt is deprotonated with a strong base such as n-butyllithium: [Ph 3 P + CH 2 R]X − + C 4 H 9 Li → Ph 3 P=CHR + LiX + C 4 H 10. Besides n-butyllithium (n BuLi), other strong bases like sodium and potassium t-butoxide (t BuONa, t BuOK), lithium, sodium and potassium hexamethyldisilazide (LiHMDS, NaHMDS, KHDMS, where HDMS = N(SiMe 3) 2), or sodium hydride (NaH) are also ...

  7. Ammonium - Wikipedia

    en.wikipedia.org/wiki/Ammonium

    Ammonium is a modified form of ammonia that has an extra hydrogen atom. It is a positively charged molecular ion with the chemical formula NH + 4 or [NH 4] +.It is formed by the addition of a proton (a hydrogen nucleus) to ammonia (NH 3).

  8. Acid catalysis - Wikipedia

    en.wikipedia.org/wiki/Acid_catalysis

    Acid catalysis is mainly used for organic chemical reactions. Many acids can function as sources for the protons. Acid used for acid catalysis include hydrofluoric acid (in the alkylation process), phosphoric acid, toluenesulfonic acid, polystyrene sulfonate, heteropoly acids, zeolites.

  9. Onium ion - Wikipedia

    en.wikipedia.org/wiki/Onium_ion

    In chemistry, an onium ion is a cation formally obtained by the protonation of mononuclear parent hydride of a pnictogen (group 15 of the periodic table), chalcogen (group 16), or halogen (group 17). The oldest-known onium ion, and the namesake for the class, is ammonium, NH + 4, the protonated derivative of ammonia, NH 3. [1] [2]