3-Methyl-1-sulfonic acid imidazolium nitrate ([Msim]NO(3)) as a new Brønsted acidic ionic liquid and nitrating agent was prepared and used for the efficient nitration of aromatic compounds (even aniline derivatives). The dramatic effect of this reagent by in situ generation of nitrogen dioxide as a radical on aromatic compounds to give nitroarenes has been studied.
Industrial-scale thermal separation processes have contributed greatly to the rise in carbon dioxide emissions. Porous materials, such as metal−organic frameworks (MOFs), can potentially reduce these emissions by achieving nonthermal chemical separations through the physical adsorption of targeted species with high selectivity. Here, we report the synthesis of the channel-based MOFs NU-2000 and NU-2001, which are constructed from threedimensional (3D) linkers, to separate the industrially relevant xylene isomers under ambient conditions by leveraging sub-Ångstrom differences in the sizes of each isomer. While the rotation of twodimensional (2D) linkers in MOFs often affords changes in pore apertures and pore sizes that are substantial enough to hinder separation efficiency, increasing the linker dimensionality from 2D to three-dimensional (3D) enables precise control of the MOF pore size and aperture regardless of the linker orientation, establishing this design principle as a broadly applicable strategy.
Cannabis plant has long been execrated by law in different nations due to the psychoactive properties of only a few cannabinoids. Recent scientific advances coupled with growing public awareness of cannabinoids as a medical commodity drove legislation change and brought about a historic transition where the demand rose over ten-fold in less than five years. On the other hand, the technology required for cannabis processing and the extraction of the most valuable chemical compounds from the cannabis flower remains the bottleneck of processing technology. This paper sheds light on the downstream processing steps and principles involved in producing cannabinoids from Cannabis sativa L. (Hemp) biomass. By categorizing the extraction technology into seed and trichome, we examined and critiqued different pretreatment methods and technological options available for large-scale extraction in both categories. Solvent extraction methods being the main focus, the critical decision-making parameters in each stage, and the applicable current technologies in the field, were discussed. We further examined the factors affecting the cannabinoid transformation that changes the medical functionality of the final cannabinoid products. Based on the current trends, the extraction technologies are continuously being revised and enhanced, yet they still fail to keep up with market demands.
Three
achiral polycyclic aromatic fluorophoresnamely, 1-pyrenecarboxylic
acid, 9-anthracenecarboxylic acid, and perylene-3,9-dicarboxylic acidwere
chosen based on their desired properties before being incorporated
into the construction of a K+-carrying gamma-cyclodextrin
(γ-CD)-based metal–organic framework (CD-MOF-1) and γ-CD-containing
hybrid frameworks (CD-HFs). Among these fluorophores, only the pyrene-carrying
one shows significant noncovalent bonding interactions with γ-CD
in solution. This fluorophore is encapsulated in a CD-HF with a trigonal
superstructure instead of the common cubic CD-MOF-1 found in the case
of the other two fluorophores. Single-crystal X-ray diffraction analysis
of the trigonal CD-HF reveals a π-stacked chiral positioning
of the pyrene-carrying fluorophore inside the (γ-CD)2 tunnels and held uniformly around an enantiomorphous 32 screw axis along the c direction in the solid-state
structure. This helix-like structure demonstrates an additional level
of chirality over and above the point-chiral stereogenic centers of
γ-CD and the axial chirality associated with the self-assembled
π-stacked fluorophores. These arrangements result in specifically
generated photophysical and chiroptical properties, such as the controlled
emergence of circularly polarized luminescence (CPL) emission. In
this manner, a complete understanding of the mechanism of chirality
transfer from a chiral host (CD-HF) to an encapsulated achiral fluorophore
has been achieved, an attribute which is often missing in the development
of materials with CPL.
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