Methyltrioctylammonium chloride is widely used as a phase transfer catalyst in organic synthesis, facilitating the transfer of reactants between immiscible phases, such as aqueous and organic layers. It is particularly effective in reactions like nucleophilic substitutions, esterifications, and polymerizations, enhancing reaction rates and yields.

In the pharmaceutical industry, it serves as an intermediate in the production of various drugs and active pharmaceutical ingredients (APIs). Its ability to stabilize emulsions and act as a surfactant makes it valuable in formulations requiring controlled drug delivery systems.

It is also employed in the extraction and separation of metals, especially in hydrometallurgical processes. Its cationic nature allows it to form complexes with anionic metal species, aiding in the purification and recovery of precious metals like gold and platinum.

Additionally, it finds applications in the textile industry as a softening agent and antistatic agent for fabrics, improving their texture and reducing static electricity. Its antimicrobial properties make it suitable for use in disinfectants and sanitizers, particularly in water treatment and surface cleaning products.