a comprehensive review of classic and modern natural gas odorants

Flammable modern natural gas besides being colorless, is also odorless. an activity like adding an odorant to gas means odorization. this operation is done to ensure that the gas can be distinguished. in other words, odorization is done to create an unpleasant smell in the air, so that the natural gas, even in small amounts, can be easily identified. improving safety and increasing the efficiency of utilization of natural gas is a very important subject due to its wide use as one of the main energy sources in industry and home consumers all around the world. so far, various types of compounds identified as odorant are increasingly being produced and formulated to be injected into natural gas. this review article describes different aspects of classical and modern natural gas odorants and their odorization process to endorse the introduction of universal sulfur-free odorants for public gas systems. after studying basic chemistry and the history of these compounds, the most important properties of odorants are presented to help recognize the most proper odorant for a specific application and its synthesis methods.