Desilication improves mesoporosity, facilitating migration of hydrated gallium ions into cavities of desilicated Ga/HZSM-5 to form (GaO)+-Brønsted phases. The bifunctional sites promote methanol conversion to aromatics.

Hydrogenation of adipic acid (AA) is a potential way to prepare 1,6‐hexanediol (HDOL). Herein, silica‐supported copper catalysts derived from copper phyllosilicates were synthesized, characterized, and tested in the hydrogenation of AA to HDOL. In a full conversion of AA, a high yield of HDOL (approximately 90 %) was obtained through the use of each Cu‐based catalyst. The turnover frequency calculated according to the consumption rate of AA was discovered to be dependent on the Cu+/(Cu0+Cu+) ratio and the reduction condition. Moreover, recycling tests showed that a catalyst derived from a copper phyllosilicate had better stability compared with Cu/SiO2 made through impregnation due to a stronger interaction between Cu and silica. The kinetic analyses based on the global rate expression and Langmuir−Hinshelwood−Hougen−Watson (LHHW) formalism of AA conversion were conducted. The possible competitive adsorption between AA and its derivatives, including hydroxycaproic acid and ϵ‐caprolactone, was thereby revealed.

NiO x -promoted Cu-based catalysts derived from CuNi phyllosilicates were synthesized, characterized, and tested in the selective hydrogenation of adipic acid to 1,6-hexanediol. The reduction of the CuNi phyllosilicate allows finely dispersed Cu0 and Cu+ on the surface. The reduced Cu36Ni5PS catalyst was found to have a higher turnover frequency for the selective hydrogenation of adipic acid than the reduced Cu41PS, Cu40Ni1PS, and Cu31Ni10PS catalysts. This catalyst is also effective at hydrogenation of succinic acid, glutaric acid, butyric acid, pentanoic acid, and hexanoic acid to their respective alcohols. The higher activity of the reduced Cu36Ni5PS catalyst is attributed to a higher oxidation state of Cu cations.

Methanol conversion to aromatics (MTA) is developing due to envisioning shortage in aromatics. In this work, HZSM‐5 (Si/Al=11.5) was desilicated with varying alkalinities and impregnated with 1 wt% Ga for MTA. Our most effective catalyst improved meso‐ and microporosities, and possessed sufficient numbers of (GaO)+‐Brønsted acid sites. Improved mesoporosity accelerates inward and outward diffusions in ZSM‐5 matrix: the former promotes hexahydrated Ga3+ transfer into cavities to form (GaO)+‐Brønsted acid phases during impregnation, while the latter suppresses cracking by shortening residence time of yielded aromatics in ZSM‐5 channels. Micropores with a narrow pore size distribution around 0.55 nm can boost aromatics selectivities, especially for o‐ and m‐xylenes. A maximal aromatics selectivity of 60.1 % was achieved at 500 °C after moderate alkali treatment (NaOH=0.05 M) of HZSM‐5. However, high aromatics output inevitably penalized catalyst durability because of higher coking rate.

No abstract