Hydrothermal synthesis of pure ZSM-22 under mild conditions

Abstract

Successful hydrothermal synthesis of pure ZSM-22 devoid of impurities is achieved under mild conditions of 433 K and horizontal stirring at 20 revolutions per minute (rpm) using Teflon-coated bar magnets to enhance gel mixing.

Organotemplate‐Free Synthesis of a High‐Silica Zeolite with a TON Structure in the Absence of Zeolite Seeds

“…The sample XRD pattern (Figure 1, a) shows a series of characteristic peaks associated with the TON structure. [19,20] The sample SEM image (Figure 1, b) exhibits pure and very uniform rod-like crystals with a length of 2-3 μm, in good agreement with the typical morphology of aluminosilicate zeolites with a TON structure, reported previously. [10] The sample Ar sorption isotherms (Figure 1, c) exhibit a steep increase in the curve at a relative pressure of 10 -6 < P/P 0 < 0.01, which is characteristic of Langmuir adsorption from the filling of the micropores.…”

Time- and space-resolved high energy operando X-ray diffraction for monitoring the methanol to hydrocarbons reaction over H-ZSM-22 zeolite catalyst in different conditions

“…The templates used in the synthesis gel of one-dimensional materials usually consist of long hydrocarbon chains with polar species at both chain ends. These templates act as structure directing agents and direct the crystallization preferentially towards similar needle-like morphologies for both ZSM-22 and ZSM-23 [29,[34][35][36][37]. This can be explained by a directing effect of the template, minimizing the surface energy of the intermediates as described in the mechanisms of crystal growth proposed by Cundy and Cox [9].…”

Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite

“…S1. The peak seen around 21.5 degrees for both samples is ascribed to cristobalite impurity which commonly co-exists with ZSM-22 [50,58,83].…”

“…was synthesized following the procedure described elsewhere [82,83] After 24 h ageing at room temperature, the resulting gel, with a composition of 8.9 K2O : 1.0 Al2O3 : 90 SiO2 : 3 K2SO4 : 27.3 DAO : 3588 H2O, was transferred to 40 ml Teflon-lined stainless steel autoclaves. Crystallization was carried out at 160 °C for 72 h in a tumbling oven (37 rpm).…”