Hydrated and dehydrated Ca-coordination polymers based on benzene-dicarboxylates: mechanochemical synthesis, structure refinement, and spectroscopic characterization

Abstract

Hydrated Ca-CPs were synthesized by milling. Dehydrated phases were obtained by thermal treatments in reversible processes.

Efficient CO2 Sequestration by a Solid–Gas Reaction Enabled by Mechanochemistry: The Case of l-Lysine

“…8,44 In mechanochemistry, the use of a liquid additive during milling, known as Liquid-Assisted Grinding (LAG), is known to be capable of sharply accelerating the reactions, improving the crystallinity of the resulting powder products and modifying the polymorphic outcome. [45][46][47][48][49][50] In our case, adding a small amount of water (50 l H2O/500 mg L-lysine) led to the formation of the carbamate bond on the two positions, as indicated by the peak at  = 165 ppm and the shoulder at  = 161 ppm in 1 H 13 C CP MAS measurement ( Figure 1, blue spectrum). In addition, 1 H 15 N CP MAS measurement displayed two peaks at  = 88 ppm and  = 74 ppm in the carbamate region ( Figure 2, blue spectrum).…”

Scale‐Up Synthesis of High Purity Calcium Terephthalate from Polyethylene Terephthalate Waste: Purification, Characterization, and Quantification

“…The bond breaking and reformation of carboxylate groups in CaTP can be verified by the changes of separation (Δ𝜈 = 𝜈 as − 𝜈 s ) between asymmetric (𝜈 as ) and symmetric (𝜈 s ) stretching frequencies in Figure 3 from 165 cm −1 in CaTP-80 to 220 cm −1 in CaTP-350. [14,37,38] The 1 H- 13 C CP MAS NMR spectra of Ca-PET indicates the existence of residue PET with a characteristic peak of the ethylene unit at 𝛿 = 60.3 ppm, which is absent from the spectra of CaTP-80 and CaTP-350 in Figure 4. The effective transformation of PET and purification of CaTP can be observed by the sharpening of signals in the NMR spectrum of CaTP-350.…”

“…In comparison, the coordination number was reduced to 6 after calcination, with a monodentate-bridging mode (six from carboxylate groups) as depicted in Figure 5e. [14,35,36]…”

“…Autoclave, hydroor solvothermal treatments have been performed since the first reported structure of calcium trihydrate CaTP by Groeneman and Atwood in 1999. [14,15] However, due to the inherent difficulties in their formation and crystallization, [12,16] the large-scale synthesis of CaTP often requires a long reaction time, high-cost reagents, and large consumption of organic solvents by the reported methods.…”

Mechanochemistry of fluoride solids: from mechanical activation to mechanically stimulated synthesis

“…Standard analytical methods like X-ray diffraction, solidstate NMR and FTIR spectroscopies, but also methods of thermal analysis, elemental analysis, BET measurements and methods of dynamic gas absorption (DVS, dynamic vapour sorption) were employed. Structure determinations were performed from X-ray diffraction powder data, since (4) the mechanochemical synthesis does not allow the formation of single crystals [86][87][88][89][90][91][92]. Figure 13 gives an insight into the structure of Ca(Sr)(p-BDC-F 4 )•4H 2 O, as one representative example of the numerous new compounds.…”