lisäysreaktion

Lisäysreaktio is a Finnish term that translates to addition reaction in English. In chemistry, an addition reaction is a type of organic reaction where two or more molecules combine to form a larger molecule. This typically occurs across a double or triple bond, where the pi bond breaks, and the atoms from the other molecule are added to the carbons that were part of the pi bond.

These reactions are characteristic of unsaturated compounds, such as alkenes and alkynes. For example, in the addition of hydrogen to an alkene, a hydrogen molecule (H2) adds across the carbon-carbon double bond, saturating it to form an alkane. Similarly, halogens, hydrogen halides, and water can be added to alkenes and alkynes.

The mechanism of addition reactions often involves the attack of an electrophile or nucleophile on the electron-rich pi system. Common types of addition reactions include electrophilic addition, nucleophilic addition, and radical addition, each depending on the nature of the attacking species and the substrate. Addition reactions are fundamental in organic synthesis, allowing for the formation of new carbon-carbon and carbon-heteroatom bonds, and are crucial in the production of many industrial chemicals and materials.