protoneren

Protoneren, or protonation in English, is the chemical process of adding a proton (H+) to an atom, molecule, or ion. Protonation changes the charge, reactivity, and often the solubility of the species, making it a central concept in acid–base chemistry and related fields.

The process occurs through proton transfer from an acid donor to a basic site on the target species. The outcome depends on factors such as pH and the relative acid–base strengths, typically described by pKa values. In solution, protonation equilibria shift with pH, producing different predominant forms of a molecule. In many reactions the site of protonation is the most basic atom or functional group: for example, amines are protonated on the lone pair to form ammonium ions, while carbonyl oxygens can be protonated to give oxonium-like intermediates.

In biochemistry, protonation states of amino acid side chains influence the overall charge of proteins, their folding, and enzymatic activity. Protonation also affects nucleic acids, cofactors, and reaction mechanisms in metabolic pathways. In analytical chemistry, protonation is exploited in mass spectrometry to generate ions such as [M+H]+, aiding molecular identification. In materials science and catalysis, controlled protonation underpins the function of proton-exchange membranes and many catalytic processes.

In Dutch, protoneren is the verb used to describe protonation, with protonatie as the standard noun. The term derives from the word proton and the Dutch verb-forming suffix -eren, reflecting its root in the concept of adding a proton.