A new method of estimating standard enthalpies of formation of zeolites

A new method to calculate the standard enthalpies (\(\Delta H_{\rm f,zeo}^0\)) of formation of zeolites is founded based on the assumption that the standard enthalpy of formation of zeolite is equal to the sum of the standard enthalpies of all oxide components and the reaction standard enthalpy change between the exchangeable ion oxide and alumina. The results show that the deviation of \(\Delta H_{\rm f,zeo}^0\) of zeolite calculated by this method is less than 0.7% compared with the experimental value of \(\Delta H_{\rm f,zeo}^0\). The standard enthalpy of formation of hypothetical [SiO2] unit in zeolite is suggested to estimate the thermodynamic stability of zeolite. It is found that the presence of crystal water in zeolite is in favor of increasing the thermodynamic stability of zeolite.