Driven by the continuous demand for optically active fluoro-containing molecules from the chemical society, the field of fluorochemistry has emerged as a hot topic recently. While protocols focusing on catalytic asymmetric fluorination, (di)fluoroalkylation, and trifluoromethylation have been well developed, elegant strategies for the synthesis of enantioenriched monofluoro- and gem-difluoroalkenes remain highly sought after. As two vital subunits of organofluorides, both monofluoro- and gem-difluoroalkenes are pervasive within many biologically active molecules. They serve as the mimics of alkenyl, enol, and peptide bonds and the carbonyl group, respectively, which may enhance the bioactivities of the parent molecules. In addition, they are active handles for the construction of other fluorinated molecules. In this review, insightful discussions on the latest achievements of the catalytic asymmetric strategies associated with the facile synthesis of both monofluoro- and gem-difluoroalkenes are provided. The related mechanism considerations, applications in streamlining syntheses, limitations, and the opportunities of the state-of-the-art methodologies will be highlighted. We hope that this will trigger novel ideas, helping in pushing current frontiers further.

A polyaspartic acid derivative (PASP-Im) as a novel scale inhibitor was synthesized by a simple green synthesis route with polysuccinimide and iminodiacetic acid as the starting materials. The as-synthesized PASP-Im was characterized via nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared spectrometry (FT-IR), and its scale inhibition performance was evaluated by a static scale inhibition method. Moreover, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and density functional theory computational studies were conducted to explore the scale inhibition mechanism of PASP-Im. The findings indicate that the as-synthesized PASP-Im exhibits better antiscale performance against the CaCO₃ deposits than the unmodified PASP because of the introduction of iminodiacetic acid group. It also can change the crystallization path of calcium carbonate from stable calcite to vaterite that is dispersible in water, thereby resulting in great changes in the morphology of the CaCO₃ scale. Furthermore, the O and N atoms in the negatively charged functional groups (such as –NH₂ and –COOH) of PASP-Im can interact with calcium ions to block the active growth point of CaCO₃ crystals, which also accounts for the excellent antiscale performance of PASP-Im. With new insights into the synergy between the functional groups of the antiscale molecule and scale-forming ions, this approach would be helpful towards the development of novel high-performance anti-scaling macromolecules.

Presence and deposition of sparingly soluble salts, known as scale, has been one of utmost damaging problems of circulating water. In industry, the scaling

A novel phosphorus-free PASP–ED ₂ A antiscalant exhibits good scale inhibition performance against calcium scale at a low concentration or a high temperature, better than that of PASP.