A novel soft-template (ST) is fabricated and successfully employed as mesoporogen to synthesis hierarchical ZSM-5 zeolites with outstanding mesoporosity and high hierarchy factors. The as-produced soft-template can connect steadily with the MFI frameworks by covalent bonds of –Si–O–Si– during the high-temperature hydrothermal crystallization process. This type of connection mode can effectively avoid the formation of amorphous materials, and the specific structure of this soft-template can efficiently introduce plentiful of mesopores with few micropores being consumed. The particles of as-synthesized hierarchical ZSM-5 zeolites are in size of about 1 μm, which are made up of nanocrystals of 60–150 nm. The structure parameters of these samples are characterized with the techniques of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, nitrogen sorption, scanning electron microscope (SEM), transmission electron microscope (TEM), NH3 temperature-programmed desorption (NH3-TPD) and thermogravimetric (TG). Due to the nature of zeolites and great microporosity, these hierarchical samples present great tolerance of hydrothermal treatment. And because of the intracrystalline mesopores, large external surface areas, and abundant accessible acid sites, whether in conversion rate of reactants or selectivity of products, the hierarchical samples exhibit excellent catalytic performance in the reactions of alkylation between benzene and benzyl alcohol, cracking of 1,3,5-tri-isopropylbenzene, and thermal cracking of low-density polyethylene (LDPE), respectively.

This study mainly reports on the preparation of Sn-imidazolates (Sn(Im)_n) supported on boron and nitrogen-doped activated carbon (AC), which proved to be highly active catalysts for the acetylene hydrochlorination. The obtained materials were characterized by FTIR spectroscopy, X-ray diffraction, N₂ physisorption, scanning electron microscopy, thermogravimetry, temperature programed desorption, and X-ray photoelectron spectroscopy. The catalytic results revealed that the Sn(Im)_n/AC materials manifest enhanced activity and long-term stability than SnCl₂/AC catalyst. Regarding the lifetime, 10%Sn(Im)_n/(10%BNAC-800) catalyst, exhibiting an acetylene conversion of 80% after 40 h of reaction, is more promising in comparison with 10%Sn(Im)_n/AC. These results indicate that the use of 2-methylimidazole improve the activity and stability of SnCl₂/AC catalysts in the hydrochlorination of acetylene. Particularly, the supports modified with boric acid and melamine can effectively increase the lifetime of Sn(Im)_n/AC catalysts.

A unique organosiloxane-polyether amine (OPA) was produced and used as mesoporogen to efficiently synthesize hierarchical ZSM-5 zeolites with great mesoporosity. We have employed silica sol and tetraethylorthosilicate, respectively, to investigate the influence of different silicon sources on hierarchical zeolites in the presence of OPA. The mesopores of synthesized samples focused on 6–15 nm, and the external surface area varied from 185 to 463 m ² g ⁻¹ where the micropore surface area was maintained at 245–334 m ² g ⁻¹ . Benefiting from the superior structure properties, these samples were used as catalysts in the reaction of methanol to propylene, and the optimal one catalysed for 180 h with methanol conversion above 95%. The as-produced OPA could connect steadily with zeolite frameworks through covalent bonds (–Si–O–Si–) during the hydrothermal crystallization process. This type of connection mode could effectively avoid the formation of amorphous phase and the special molecular structure of OPA could efficiently introduce abundant mesopores with few micropores being consumed. The samples synthesized with silicon sol were made up of quasi-circular particles of about 800 nm in size and further consisted of nanocrystals of 40 nm, and the samples produced with TEOS have a particle size of about 1–2 µm aggregated with nanocrystals of 300 nm.