芳烃官能化有机硅膜的制备及丙烯/丙烷分离性能

Two organosilica presursors, 1,4-bis (triethoxysilyl) benzene (BTESB) with benzene bridges and 4,4'-bis (triethoxysilyl) biphenyl (BTESBPh) with biphenyl bridges were utilized for the fabrication of organosilica membranes via the sol-gel strategy. The two membranes were applied to the gas separation. At 25℃, BTESB membrane displayed a C₃H₆ permeance of 3.4×10^-9mol/(m²·s·Pa)and C₃H₆/C₃H₈ selectivity of 9.6. Nevertheless, BTESBPh membrane showed a C₃H₆permeance of 1.7×10^-8mol/(m²·s·Pa) and a comparable C₃H₆/C₃H₈ selectivity of 10.5. BTESBPh membrane networks with biphenyl bridged structures were much looser and could achieve higher gas permeance. The π-π interactions occurred between the big π bond in the benzene ring and the C==C bond in the C₃H₆ molecules, which was beneficial for the preferential adsorption and permeation of the C₃H₆ molecules. The biphenyl bridges in BTESBPh membranes enhanced the adsorption and permeation process, as evidenced by the increased C₃H₆/C₃H₈ selectivity of the BTESBPh membrane under low testing temperatures. This study could provide a reference for the development of high-performance propylene/propane separation membranes.