화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.52, No.3, 1190-1196, 2013
Low-Cost Synthesis of Titanium Silicalite-1 (TS-1) with Highly Catalytic Oxidation Performance through a Controlled Hydrolysis Process
Titanium silicalite-1 (TS-1) has been successfully synthesized in ultralow molar ratio of TPAOH/SiO2 by two-step and multistep hydrolysis process, where the molar ratio of tetrapropylammonium hydroxide/silica (TPAOH/SiO2) could be reduced to 0.08 and 0.065, respectively. Combined characterization of X-ray diffraction (XRD), N-2 adsorption desorption, scanning electron microcopy (SEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis spectroscopy, and thermal gravimetric (TG) analysis shows that currently synthesized TS-1 samples have the typical "blackberry" morphology, and the particle size is around 300-400 nm, similar to that of the conventional TS-1 synthesized at a high molar ratio of TPAOH/SiO2 (>0.18). Additionally, currently synthesized TS-1 exhibits excellent catalytic oxidation performance in epoxidation of alkene and ammoximation of ketone, even better than that of conventional TS-1. Obviously, fast hydrolysis of a small part of TEOS at a high concentration of TPA(+) in the first step induces more nuclei, which in turn accelerates crystallization in the subsequent step. Therefore, effective utilization of TPAOH to build the TS-1 framework is significantly increased. This strategy can greatly reduce the synthesis cost of TS-1, which is suitable for synthesis of TS-1 on an industrial scale.