Synthesis of High-Performanced Titanium Silicalite-1 Zeolite at Very Low Usage of Tetrapropyl Ammonium Hydroxide

Abstract

A novel method for the synthesis of high-performanced titanium silicalite-1 (TS-1) zeolite at a very low usage of tetrapropylammonium hydroxide (TPAOH) was developed in this work. The method involved a temperature-programmed hydrothermal crystallization (TPHC) of a batch with a TPAOH/SiO 2 molar ratio of as low as 0.05, being 5 times smaller than that employed in the conventional synthesis, in which the TPAOH was entirely provided by a TS-1 precursor sol. The characterizations of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance ultraviolet− visible spectroscopy (DR UV−vis), and scanning electron microscopy (SEM) indicated that the TS-1 synthesized via the novel method possessed a uniform crystal size of ∼0.3 μm, a very high crystallinity and a considerably large content of framework Ti (2.33 mol %). The TS-1 had been employed as the catalyst for the ammoximation of cyclohexanone, of which the influencing factors were systematically investigated. It was shown that the TS-1 synthesized via the novel method possessed a very high performance, which is even better than for those synthesized via the conventional method both in this work and in the literature work.

Hollow TS-1 mesocrystals: hydrothermal construction and high catalytic performances in cyclohexanone ammoximation

“…[27][28][29][30][31][32] The presence of micropores in zeolites limits the diffusion of bulky reactants to internal catalytic sites, which reduces the activity of catalyst. [35][36][37][38][39][40] The complicate separation processes from reaction mixture and the easy aggregation of nanosized zeolites during synthesis and catalytic reactions limit seriously their development and industrial application. 33,34 Nanocrystallites of 75 TS−1 zeolite was initially researched and developed to overcome this shortcoming.…”

Effect of triethylamine treatment of titanium silicalite-1 on cyclohexanone ammoximation in a continuous system

“…In addition, although anatase is identified by UV-Vis, it is not detected by XRD. This indicates that the anatase has a high dispersion in the TS-1 crystals [59]. Fig.…”

Hollow Titanium Silicalite Zeolite: From Fundamental Research to Commercial Application in Environmental-Friendly Catalytic Oxidation Processes

“…And the band intensity ratio between 960 and 800 cm −1 (I 960 / I 800 ) is relevant with the framework Ti content [41,42]. Thus, it is concluded more tetrahedral Ti species have been inserted into framework sites after the post-synthesis treatment, due to the higher I 960 /I 800 value of HTS than that of TS-1 zeolite (as shown in Figure 4).…”