Vapor-phase synthesis of c-caprolactam (e-C) from cyclohexanone oxime (CHO) has been studied at 300-400degreesC and atmospheric pressure using AISBA-15(X) catalysts with different Si/Al mol ratios X in a fixed-bed, integral-flow reactor. The catalysts were characterized with ICP-AES, XRD, TEM, N-2 adsorption, Al-27 and Si-29 MAS-NMR, FT-IR and TPD of ammonia. A decrease of X value in AISBA-15(X) diminishes both the BET surface area and the unit cell length but enhances the acid amount. The catalytic activity correlates with the catalyst acidity. AISBA-15(10) exhibits excellent catalytic performance.