Tetrapropylammonium hydroxide solution is widely used in the synthesis of zeolites, particularly ZSM-5, due to its role as a structure-directing agent. It helps in organizing the framework structure during the crystallization process, ensuring the formation of specific pore sizes and shapes. In the field of organic synthesis, it serves as a phase-transfer catalyst, facilitating reactions between compounds in different phases, such as aqueous and organic. Additionally, it is employed in the preparation of quaternary ammonium compounds, which are essential in various industrial applications, including surfactants and disinfectants. Its use in electrochemical applications, such as in the preparation of ion-selective electrodes, is also notable due to its ionic properties.