Rapid and economical conversion of Beta zeolite to SSZ-13 zeolite

Abstract

Pure SSZ-13 zeolite has been hydrothermally synthesized by converting Beta zeolite in the presence of template N, N, N-trimethyl-1-adamantanamine hydroxide (TMAdaOH) and additional silica (Na 2 SiO 3 ). The effects of TMAdaOH, NaOH and H 2 O amounts on the crystallization process are under discussion. When TMAdaOH/SiO 2 ratio is no less than 0.02, NaOH/SiO 2 ratio is around 0.34 and H 2 O/SiO 2 ratio is within a wide range, pure SSZ-13 zeolite can be formed. The crystallization mechanism is investigated detailedly with XRD, FE-SEM, FT-IR and UV Raman techniques. Using Beta zeolite as raw material, pure SSZ-13 zeolite could be formed after crystallization for only 22 h at 150 °C. In the conversion from Beta zeolite, the five-membered rings (5MRs) in the framework are decomposed into four-membered rings (4MRs) and six-membered rings (6MRs), which could be rearranged into double six-membered rings (D6Rs) and then crystallized into the SSZ-13 zeolite in the system. Moreover, the calcined SSZ-13 zeolite prepared from Beta zeolite possesses slightly lower surface area and pore volume, and stronger acidity comparing with the sample by amorphous raw materials. • The amount of NaOH is important to achieve the conversion of Beta to SSZ-13 zeolite. • The amount of TMAdaOH in this method is greatly reduced compared to the conventional method from amorphous raw materials. • The crystallization rate of SSZ-13 from Beta zeolite is obviously enhanced. • The conversion mechanism of SSZ-13 from Beta zeolite is discussed detailedly.