CatalystsBrønsted

CatalystsBrønsted, also known as Brønsted catalysts, are substances that increase the rate of a chemical reaction by donating a proton (H+) to a reactant. This donation lowers the activation energy of the reaction, allowing it to proceed faster or at a lower temperature. Brønsted catalysts are not consumed in the overall reaction and can be recovered and reused. They are typically strong acids or weak acids that can readily release a proton.

The mechanism of Brønsted catalysis involves the protonation of a reactant, making it more reactive towards the desired transformation. For example, in esterification reactions, an acid catalyst protonates the carbonyl oxygen of a carboxylic acid, increasing the electrophilicity of the carbonyl carbon and making it more susceptible to nucleophilic attack by an alcohol. After the reaction, the catalyst is regenerated, often by deprotonation.

Common examples of Brønsted catalysts include mineral acids like sulfuric acid (H2SO4) and hydrochloric acid (HCl), as well as organic acids such as acetic acid (CH3COOH) and p-toluenesulfonic acid (TsOH). Solid acid catalysts, like zeolites and ion-exchange resins with acidic functional groups, are also widely employed in industrial processes due to their ease of separation from the reaction mixture. Brønsted catalysis is a fundamental concept in chemistry with widespread applications in organic synthesis, industrial production, and biochemical processes.