1. If, in a homogenous mixture, also known as solution, the major component by volume is a liquid, is is called the solvent.
eg: Stirring 10 ml of ethanol, a liquid, in 100 ml of water, a liquid, creates a solution in which the solvent is water.
2. To carry out most organic reactions, the reactants and, if any, the catalyst are dissolved in a liquid, called the solvent, and the resultant solution is subjected to the reaction conditions.
To effect the above reaction, reactants 1 and 2 are dissolved in CCl4, and the resultant solution is irradiated.
Requirements of the solvent of a reaction:
- The solvent must not react with the reactants, the products, or, if any, the catalyst under the reaction condition, unless intended to (eg: solvolysis).
- The solvent must not decompose under the reaction conditions.
- The boiling point of the solvent must be equal to (reflux conditions) or lower than the reaction temperature.
see also protic solvent, aprotic solvent, nucleophilic solvent