With the potential application of biomass-derived feedstock upgradation to sustainable aviation fuels, it is essential to enhance the hydroisomerization performance of ZSM-22 zeolite while improving its resistance to residual oxygen-containing compounds. As the defect sites in the ZSM-22 zeolite, the abundant Si-OH groups are closely related to the catalytic performance and stability, serving as the main attack sites for the generated water. In this work, liquid-mediated defect-healing treatment is performed to heal Si-OH to Si-O-Si, leading to the enhancement of the crystallinity and pore connectivity without affecting the Si/Al, micropore volume, and morphology and preventing the micropores blockage and dealumination caused by conventional silylation and silication procedures. The outcome of the declined Si-OH groups is the reduction of the Lewis acid site without altering the Brønsted acidity. In the n-dodecane hydroisomerization, the catalyst obtained by the liquid-mediated defect-healing treatment route shows an increased conversion and isomer yield compared to the parent and healed catalysts prepared by other healing methods. This is mainly due to enhanced confinement of the micropore void, resulting in decreased apparent activation energy and reduced yield to multi-branched isomers prone to cracking. Furthermore, the healed catalyst exhibits improved resistance and structure stability in the hydroisomerization of feedstocks containing butanol. The work provides a prospective application of ZSM-22 zeolite in the hydroisomerization for complex and severe reactants through the essential Si-OH healing method.
The sluggish interfacial mass transfer usually hinders the achievement of high-efficiency catalytic transformation of biomass, especially for solvent-free immiscible reagent systems. Herein, amphiphilic hybrid Ti-containing catalysts in situ incorporated with organic groups (Cn-Ti-HMS) were developed for boosting biphasic solvent-free epoxidation of methyl oleate (MO) with H 2 O 2 . Benefiting from the mutual effect between organic/inorganic precursors, the resulting low-defect catalysts exhibit well-mediated surface hydrophilic/hydrophobic balance and porosity by incorporating alkyl groups. Such mediation effect exhibits two superiorities: i) accelerated adsorption of reactants by amphiphilicity; ii) boosted substrate or product diffusion by porosity property. As such, remarkably promoted catalytic properties were achieved when compared with conventional Ti-HMS. Typically, methyl-functionalized C1–Ti-HMS-50 displays the optimal catalytic performance with a 95% conversion of MO. Further mechanism study recognizes the dominant role of surface wettability and Si–OH defects content in influencing MO conversion and epoxidized MO selectivity.
危险品化学品经营许可证（带存储）