The Metal–Organic Framework MIL‐53(Al) Constructed from Multiple Metal Sources: Alumina, Aluminum Hydroxide, and Boehmite

Abstract

Three aluminum compounds, namely alumina, aluminum hydroxide, and boehmite, are probed as the metal sources for the hydrothermal synthesis of a typical metal-organic framework MIL-53(Al). The process exhibits enhanced synthetic efficiency without the generation of strongly acidic byproducts. The time-course monitoring of conversion from different aluminum sources into MIL-53(Al) is achieved by multiple characterization that reveals a similar but differentiated crystallinity, porosity, and morphology relative to typical MIL-53(Al) prepared from water-soluble aluminum salts. Moreover, the prepared MIL-53(Al) constructed with the three insoluble aluminum sources exhibit an improved thermal stability of up to nearly 600 °C and enhanced yields. Alumina and boehmite are more preferable than aluminum hydroxide in terms of product porosity, yield, and reaction time. The adsorption performances of a typical environmental endocrine disruptor, dimethyl phthalate, on the prepared MIL-53(Al) samples are also investigated. The improved structural stability of MIL-53(Al) prepared from these alternative aluminum sources enables double-enhanced adsorption performance (up to 206 mg g(-1)) relative to the conventionally obtained MIL-53(Al).

Continuous‐Flow Microwave Synthesis of Metal–Organic Frameworks: A Highly Efficient Method for Large‐Scale Production

“…This approach was adapted by the same group for CF synthesis of MIL‐53(Al), increasing the STY up to a value of 1300 kg m −3 d −1 (Supporting Information, Table S5) . Alternatively, a method employing aluminum oxide as the metal source was also reported, which furnishes product with high yield but low STY owing to a long reaction time . The crystallization kinetics of this MOF was investigated under MW irradiation, but no information about the yield of the process was reported.…”

“…[26] Alternatively, amethodemploying aluminumo xide as the metal source was also reported, which furnishes product with high yield butl ow STY owing to al ong reactiont ime. [39] The crystallization kinetics of this MOF was investigated under MW irradiation, [40] but no information about the yield of the process was reported. Our CFMW preparation of MIL-53(Al) is the first report of aM W-assisted synthesis of this MOF,a nd is simultaneously the most productivea nd highest yielding process described to date.…”

In situ Raman and FTIR spectroscopic study on the formation of the isomers MIL-68(Al) and MIL-53(Al)

“…25,26 Aluminum-based MOFs are especially interesting due to their high thermal stability (>500 C) and relatively low synthesis costs. 27 While many reports exist on the synthesis of MIL-53(Al) with Al 3+ as the metal center, 18,[28][29][30] the synthesis of MIL-68(Al) is more challenging. 31 Oen, the synthesis protocols for MIL-68(Al) result in a mixture of MIL-53(Al) and MIL-68(Al).…”

Porous Nickel‐Alumina Derived from Metal‐Organic Framework (MIL‐53): A New Approach to Achieve Active and Stable Catalysts in Methane Dry Reforming

“…An additional benefit is the occurrence in this structure of aluminum bridging hydroxy groups lying along the inorganic chains that can interact with the nickel precursors and hence act as anchorage sites. Moreover, MIL‐53(Al) is made from the assembly of relatively inexpensive components, namely hydroxy‐aluminum species and terephthalate linkers, which can be extracted from natural or recycled feedstocks making this MOF‐derived strategy economically and ecologically viable.…”