Selective epoxidation of olefins using metal incorporated mesoporous molecular sieves

Abstract

Catalysts have been used in the chemical industries for more than newline100 years. Many large-scale industrial processes proceed efficiently with the newlinesupport of catalysis. The word catalyst originates from the Greek word kata newlinewhich means down and luein which means breaking. The word catalysis newlinewas first coined by J. J. Berzelius in 1836. A catalyst is defined as a substance newlinethat increases the rate of a chemical reaction without being substantially newlineconsumed in the reaction (Bond et al. 1992).From the 18thcentury, it has been seen that addition of certain newlinecompounds increases the rate of the chemical reactions and that these newlinecompounds can be recovered after the reaction. In 1835, Berzelius coined the newlineterm catalyst to indicate these compounds which accelerates a reaction but newlinedoes not involve in the reaction. The action of these compounds in a reaction newlineis called catalysis . Here, catalyst adsorbs reactant molecule, converts it into newlinea product which desorbs from the catalyst surface leaving it free and available newlinefor successive reactions. In many cases, the presence of a catalyst newlinethermodynamically lowers the Activation Energy (Ea) of the reaction. In newlineother words, less free energy is required to reach the transition state newline(Chorkendoff and Niemantsverdri 2006 newline newline