Green Synthesis of a New Al‐MOF Based on the Aliphatic Linker Mesaconic Acid: Structure, Properties and In Situ Crystallisation Studies of Al‐MIL‐68‐Mes

Abstract

A new aluminium metal-organic framework (MOF), based on the short aliphatic linker molecule mesaconic acid (H Mes; methylfumaric acid) is reported. Al-MIL-68-Mes with composition [Al(OH)(O C-C H -CO )]⋅n H O is obtained after short reaction times of 45 minutes under mild, aqueous synthesis conditions (95 °C). It exhibits a kagome-like framework structure with large hexagonal, and small trigonal channels (diameters of ≈6 and ≈2 Å, respectively) and a specific surface area of S ≈1040 m g (V =0.42 cm g ). A sigmoidal vapour sorption isotherm for water, and uptakes of water and methanol above 30 wt. % were observed. Al-MIL-68-Mes is stable against water ad-/desorption and its thermal stability is 350 °C in air. The proton conductivity for the hydrated MOF showed values up to 1.1×10 S cm at 130 °C and 100 % relative humidity, which exceeds the values observed for the non-hydrated compound by up to four orders of magnitude. Using synchrotron radiation the crystallisation of the MOF by in situ PXRD was also studied at temperatures from 80 to 100 °C. Kinetic evaluation revealed that the induction periods and crystallization times vary depending on the synthesis batch, but the rate limiting steps are consistently observed.

A green metal–organic framework to monitor water contaminants

“…The crystal structure of CIM-80 consists of a kagome-like MIL-68 framework with two different type of channels: large hexagonal and small triangular pores of 6 and 2Å diameters, respectively, with the methyl groups of the mesaconic acid directed towards the large pores. 20 Aer activation at 150 C, and reduced pressure overnight, the N 2 adsorption isotherm at 77 K leads to a BET surface area for this material of 891 m 2 g À1 . This value is close to the reported value of 1040 m 2 g À1 .…”

“…At the time preparing this manuscript, this material has been reported with a similar green synthetic approach. 20 To evaluate the performance of this greener CIM-80 as novel sorbent in D-mSPE to monitor waters, 22 different pollutants are selected for being representative analytes of different families. The D-mSPE method is completely optimized and validated with CIM-80; while comparing its analytical performance to that of MIL-53(Al) and other materials.…”

In Situ Monitoring of Particle Formation with Spectroscopic and Analytical Techniques Under Solvothermal Conditions

“…While several studies have focused on the properties of MOFs, comparatively fewer studies have faced the challenges of unravelling their formation mechanism via in situ studies. Predominately, in situ X‐ray diffraction techniques have been used to shed light on the formation mechanism of various MOFs . Accordingly, the long‐range order of MOFs has been studied by in situ small‐ and wide‐angle X‐ray scattering (SAXS/WAXS) , static light scattering , , and energy dispersive X‐ray diffraction (EDXRD) and EXAFS , .…”

Greener synthesis of chemical compounds and materials

“…An Al-MOF ‘Al-MIL-68-Mes' (figure 6), containing small trigonal and large hexagonal channels, having high specific surface area 1040 m 2 g −1 , chemical composition [Al(OH)(O 2 C-C 3 H 4 -CO 2 )] · n H 2 O and derived from mesaconic acid (methylfumaric acid H 2 Mes), was prepared from mesaconic acid, NaOH and Al 2 (SO 4 ) 3 · 18H 2 O in mild conditions at 95°C in water for 45 min under MW [92]. The formed MOF exhibited a considerable chemical and thermal (350°C) stability.…”