요 약본 연구에서는 3-Methylpentane을 포함하는 Ethylene glycol monopropyl ether (C 3 E 1 ) 및 Ethylene glycol isopropyl ether (iC 3 E 1 ) 계면활성제 혼합물에 대한 2성분계 기-액 상 평형을 서로 다른 온도 조건(303.15, 318.15, 333 Abstract − Isothermal vapor liquid equilibria for the binary system of 3-methylpentane with ethylene glycol monopropyl ether (C 3 E 1 ) and ethylene glycol isopropyl ether (iC 3 E 1 ) were measured at 303.15, 318.15, and 333.15K. In our previous work, phase equilibria for the binary system of C 3 E 1 mixtures were investigated according to the chain length of alkane, alcohol or those isomer. But in this study, we discussed the different effect of C 3 E 1 and its isomer, iC 3 E 1 , on the phase equilibria. The measured systems were correlated with a Peng-Robinson equation of state (PR EOS) combined with Wong-Sandler mixing rule for the vapor phase, and NRTL, UNIQUAC, and Wilson activity coefficient models for the liquid phase. All the measured systems showed good agreement with the correlation results. And it was found that the phase equilibria showed very little difference between the iC 3 E 1 mixture system and the C 3 E 1 mixture system.