Using a continuous flow apparatus, in a binary system in supercritical CO 2 (scCO 2 ), the solubility of trioctylamine (TOA) and tridodecylamine (TDA) have been measured as a function of equilibrium time, pressure, and temperature. Solubility of TOA in scCO 2 , was measured in the pressure range of 80 to 400 bar at different temperatures of 35°C, 40°C, 45°C, 55°C, and 65°C. The solubility of TDA in scCO 2 , was measured at temperatures of 35°C, 45°C, and 55°C in the same pressure range. The solubility of TOA and TDA in scCO 2 was calculated as mole fraction (y 2 ), amount of solute per L of expanded CO 2 gas (S 1 ) and amount of solute per L of scCO 2 (S 2 ). The solubility of TOA in scCO 2 increases with pressure but showing different trends at different temperatures. At 35°C and 40°C, the solubility increases with pressure up to 125 bar and then was saturated at upper pressures. At 45°C the solubility increases with pressure up to 250 bar and then saturation was observed. At 55°C and 65°C the solubility of TOA are increased almost linearly until 400 bar and saturation was not observed. In the case of TDA, at 35°C and 45°C the solubility increases with pressure up to 150 bar and then reaches saturation state. At 55°C the solubility increases with pressure up to 350 bar and then saturation was observed. The experimental results for solubility data of TOA and TDA were correlated using Chrastil, Bartle, and Mendez-Santiago and Teja equations. With these models the solubility of TOA and TDA in the same pressure range and low temperatures (35, 40 and 45) °C can be predicted. Among which the Chrastil equation were able to better correlate the solubility data of TOA. While for solubility data of TDA correlation, Bartle equation and Mendez-Santiago and Teja model was suitable but Chrastil equation did not correlate the solubility data of TDA as good as other equations. Using supercritical fluid extraction technique some of carboxylic acids such as benzoic acid, maleic acid, phthalic acid, and phthalic anhydride were extracted from solid waste of Farabi Petrochemical Company of Bandare Imam Khomeini. Extraction was carried out with continuous flow of scCO 2 from extraction cell with colection times of 15 min at temperatures of 45°C, 55°C and 75°C in the pressure range of (100 to 300) bar. Extracted samples were dissolved in ethanol and analyzed with GC-FID. The total extraction yield of extractrd species at temperature of 45°C and pressure of 100 bar, were 32% for extraction time of 150 min, while at temperature of 75°C and pressure of 300 bar for extraction time of 75 min the yield was 95%. At temperature of 55°C and pressure of 150 bar at first 15 min of extraction, all of the benzoic acid in the sample were extracted.