Synthesis of colloidal silicalite-1 at high temperatures

Abstract

Stable colloidal suspensions of silicalite-1 were prepared by hydrothermal treatment of clear precursor suspensions at high temperatures, 150 °C and 170 °C. The precursor suspensions were pretreated prior to hydrothermal treatment. Different pretreatment procedures were applied, namely ultrasonic treatment or heating at 45-60 °C, for different periods of time. In all cases, the size of the crystals decreased with increasing the time of pretreatment. The pretreatment procedure was found to influence the behavior of the tetrapropylammonium hydroxide solution used as structure-directing template during hydrothermal treatment. Colloidal stability of pretreated samples was improved compared to samples prepared by direct hydrothermal treatment.

Grafting Ti Sites on Defective Silicalite-1 via TiCl4 Chemical Vapor Deposition for Gas-Phase Epoxidation of Propylene and H2O2 Vapor

“…Characterization on the Basic Physicochemical Properties of S-1zeolite. Figure 2A shows that the parent S-1 zeolite hydrothermally synthesized in this study according to the reported method 12 was well-crystallized. It had all the five characteristic peaks of the MFI topology (2θ = 7.9, 8.8, 23.1, 23.8, and 24.3°), and there was no diffraction peak related to impurity.…”

“…Parent silicalite-1 (S-1) zeolite was synthesized followed a reported hydrothermal method. 12 First, a 220 g (25 wt. %) tetra-propylammonium hydroxide (TPAOH) solution was added dropwise into 312 g tetraethyl orthosilicate (TEOS) while stirring vigorously.…”

“…Parent silicalite-1 (S-1) zeolite was synthesized followed a reported hydrothermal method . First, a 220 g (25 wt.…”

Isobutane Dehydrogenation Assisted by CO2 over Silicalite‐1‐Supported ZnO Catalysts: Influence of Support Crystallite Size

“…Submicron and micrometer Silicalite‐1 zeolites were synthesized according to the literature . Typically, tetrapropylammonium hydroxide (TPAOH, 25 wt% aqueous solution), tetraethyl orthosilicate (TEOS) and distilled deionized water were mixed with stirring at room temperature to form a clear gel with a molar composition of m TPAOH : 25SiO 2 : 480H 2 O (where m = 3, 6 and 9, respectively).…”

Chromium Oxide Supported on Silicalite-1 Zeolite as a Novel Efficient Catalyst for Dehydrogenation of Isobutane Assisted by CO2

“…Silicalite-1 zeolite was synthesized as follows [51]. Tetrapropylammonium hydroxide (TPAOH, 25% aqueous solution), tetraethyl orthosilicate (TEOS), and distilled water were mixed to obtain a clear suspension (9TPAOH:25SiO 2 :480H 2 O, molar composition).…”