Synthesis of SSZ-13 zeolite with zeolite L-added synthesis gel absent from additional aluminum source

Abstract SSZ-13 zeolite with a SiO 2 /Al 2 O 3 ratio in the range of 26–183 was synthesized by adding zeolite L in the synthesis gel absent from additional aluminum source, and the effects of SiO 2 /Al 2 O 3 and N,N,N-trimethyladamantammonium hydroxide (TMAdaOH)/SiO 2 ratios on the crystallization were investigated. The crystallization mechanism was studied with X-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy and 29 Si and 27 Al MAS NMR spectroscopy techniques. It is shown that the SiO 2 /Al 2 O 3 and TMAdaOH/SiO 2 ratios have a significant effect on the acidity, and thus, the methanol-to-olefins (MTO) performance of SSZ-13. The co-presence of TMAdaOH, NaOH and extra silica source (SiO 2 ) is necessary for formation of SSZ-13. The crystallization of SSZ-13 occurs by decomposing structure of zeolite L into double six- and four-membered rings that subsequently restructure into CHA topology under the direction of TMAdaOH, and further induce the nucleation and crystal growth. It is noteworthy that the Al species in zeolite L directly transform into those of SSZ-13 without forming monomeric species. The prepared SSZ-13 shows higher catalytic stability and selectivity to ethylene and proplyene than the conventionally synthesized sample from amorphous aluminosilicate gel in MTO reaction.