In recent years, gas hydrate has been widely used in various fields such as energy storage and separation processes. One of the examples of the separation process is the use of gas hydrate in the desalination of salty water. Because during hydrate formation, the salts are not included in the hydrate structure. Therefore, this method can be a suitable substitute for other methods such as reverse osmosis and evaporation. The aim of this study is to measure the thermodynamic equilibrium conditions of carbon dioxide gas hydrate formation and Persian Gulf water sample without and with the presence of the promoter, tetrabutylammonium bromide. Promoters are chemicals that have the ability to form gas hydrates at lower pressures and higher temperatures. The constant volume pressure search method, was used to obtain hydrate phase equilibrium data. Equilibrium data on hydrate formation conditions for Persian Gulf water samples and carbon dioxide have been obtained in the temperature range of 275 to 279 Kelvin. By examining these data with the equilibrium hydrate formation data for carbon dioxide in the presence aqueous solution of sodium chloride, it was determined that these data are in good agreement with the equilibrium data for the formation of carbon dioxide hydrate in the presence of a 5% by weight aqueous solution of sodium chloride. This consistency can be useful for modeling. Also, in order to investigate the effect of promoters, semi-clathrate hydrate equilibrium formation conditions data were measured and reported for Persian Gulf water samples and carbon dioxide gas with 3% and 7% by weight of tetrabutylammonium bromide in the temperature and pressure range of 273 to 281 Kelvin and 16 to 38 bar, respectively. The obtained data showed that the equilibrium data of tetrabutylammonium bromide semi-clathrate hydrate is formed at higher temperatures and lower pressures than carbon dioxide hydrate and the Persian Gulf water sample. Using the Clapeyron method, the enthalp