Phase behavior of undecane-tetradecane （n-C11H24-C14H3o, C11-C14） mixtures in bulk and confined in SBA-15 have been studied using differential scanning calorimetry. The bulk C11-C14 system shows multiple phase regions due to rotator phase. Confined in the pores of SBA-15 （pore diameters 3.8- 7.8 rim）, the mixtures only show a melting boundary of a straight line and a curve, respectively. In SBA- 15 （ 17.2 nm）, phase behavior of the mixtures has some similarity to that of the bulk. Under confinement, the phase diagrams of the mixtures vary with the pore size, temperature, and compositions.
Phase behavior of normal decane-dodecane （n-CloH2/-CI2H26, Clo-C12） system confined in SBA-15 （Santa Barbara Amorphous, pore diameters 3.8, 7.8, and 17.2 nm） has been studied by using differential scanning calorimetry. It has been found solid-liquid phase diagram of the C10-C12/SBA-15 system is composed of a straight line （3.8 nm）, a curve （7.8 nm） and a loop line （17.2 nm）. The growth of the phase diagram clearly shows the size effect on phase behavior of binary alkanes. Phase behavior has been compared among the systems C10H22-CI2H26]SBA-15, C12H26-C14H3o/SBA-15 and C14H30-C16H34/SBA-15.
