Synthesis TS-1 nanozelites via L-lysine assisted route for hydroxylation of Benzene

Computational and experimental insights into the spectroscopy, electronic states, and molecular docking of (2S)-2,6-diaminohexanoic acid [DAHA]

This paper presents a theoretical analysis of the L-Lysine molecule using the DFT (density functional theory) method with a 6-311+ + G(d,p) basis set, a quantum-mechanical atomistic simulation method. The research encompasses the analysis of optimized chemical structure, vibrations, FMO, ELF, NLO, RDG, etc., to study the molecule's intensive properties, stability, and other biological activities. IR and UV spectra were analysed for the spectrochemical study, and the VEDA program was used to determine the PED values. The chemical reactivity of the molecule was identified through analysis of the Frontier molecular orbitals, Fukui, and molecular electrostatic potential. The electron localization function and reduced density gradient were determined to understand bonding and electronic structure. The temperature dependence on the properties of the molecule was estimated. The optical properties of the molecule were discussed by analyzing the non-linear optical property. The feasibility of the molecule as a therapeutic drug was examined using the drug likeness concept. Molecular docking analysis was conducted to acquire the best ligand-receptor complex and to study the molecule's biological activity.

Review and perspectives on TS-1 catalyzed propylene epoxidation

Titanium silicate zeolite (TS-1) is widely used in the research on selective oxidations of organic substrates by H2O2. Compared with the chlorohydrin process and the hydroperoxidation process, the TS-1 catalyzed hydroperoxide epoxidation of propylene oxide (HPPO) has advantages in terms of by-products and environmental friendliness. This article reviews the latest progress in propylene epoxidation catalyzed by TS-1, including the HPPO process and gas phase epoxidation. The preparation and modification of TS-1 for green and sustainable production are summarized, including the use of low-cost feedstocks, the development of synthetic routes, strategies to enhance mass transfer in TS-1 crystal and the enhancement of catalytic performance after modification. In particular, this article summarizes the catalytic mechanisms and advanced characterization techniques for propylene epoxidation in recent years. Finally, the present situation, development prospect and challenge of propylene epoxidation catalyzed by TS-1 were prospected.

Tetrapropylammonium Hydroxide Treatment of Aged Dry Gel to Make Hierarchical TS-1 Zeolites for Catalysis

This work presents the development and systematic study of a method to prepare hierarchical titanium silicalite-1 (TS-1) zeolites with high tetra-coordinated framework Ti species content. The new method involves (i) the synthesis of the aged dry gel by treating the zeolite precursor at 90 °C for 24 h; and (ii) the synthesis of hierarchical TS-1 by treating the aged dry gel using tetrapropylammonium hydroxide (TPAOH) solution under hydrothermal conditions. Systematic studies were conducted to understand the effect of the synthesis conditions (including the TPAOH concentration, liquid-to-solid ratio, and treatment time) on the physiochemical properties of the resulting TS-1 zeolites, and the results showed that the condition of a TPAOH concentration of 0.1 M, liquid-to-solid ratio of 1.0, and treatment time of 9 h was ideal to enable the synthesis of hierarchical TS-1 with a Si/Ti ratio of 44. Importantly, the aged dry gel was beneficial to the quick crystallization of zeolite and assembly of nanosized TS-1 crystals with a hierarchical structure (S _ext = 315 m² g^-1 and V _meso = 0.70 cm³ g^-1, respectively) and high framework Ti Species content, making the accessible active sites ready for promoting oxidation catalysis.

Recent advances in the synthesis of TS-1 zeolite

Heteroatomic zeolites as an important class of zeolites, have been widely applied in industrially catalytic processes due to their unique properties. As one of the most representative heteroatomic zeolites, titanosilicate zeolites have been extensively used in the selective oxidations of organic substrates with H2O2 such as cyclohexanone ammoximation, epoxidation of alkenes, and phenol hydroxylation. In this review, recent advances in the synthesis of TS-1 zeolite are briefly summarized, including use of low-cost raw materials (organic templates, silicon, and titanium sources), development of new synthesis routes (post-treatment synthesis, dry-gel conversion synthesis, solvent-free synthesis, and microwave-assisted synthesis), and new strategy for enhanced mass transfer in TS-1 crystals (synthesis of hierarchical and nanosized TS-1 zeolite). This review might help researchers to have a deep understanding on the synthesis of TS-1 zeolite and provide a new opportunity for the design and preparation of highly efficient TS-1 catalysts in the future.