In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Functionalizing Polystyrene with N-Alicyclic Piperidine-Based Cations via Friedel-Crafts Alkylation for Highly Alkali-Stable Anion-Exchange Membranes, published in 2020-06-23, which mentions a compound: 111-24-0, Name is 1,5-Dibromopentane, Molecular C5H10Br2, SDS of cas: 111-24-0.
Different anion-exchange membranes (AEMs) based on polystyrene (PS)-carrying benzyltrimethyl ammonium cations are currently being developed for use in alk. fuel cells and water electrolyzers. However, the stability in relation to these state-of-the-art cations needs to be further improved. Here, we introduce highly alkali-stable mono- and spirocyclic piperidine-based cations onto PS by first performing a superacid-mediated Friedel-Crafts alkylation using 2-(piperidine-4-yl)propane-2-ol. This is followed by quaternization of the piperidine rings either using iodomethane to produce N,N-di-Me piperidinium cations or by cyclo-quaternizations using 1,5-dibromopentane and 1,4-dibromobutane, resp., to obtain N-spirocyclic quaternary ammonium cations. Thus, it is possible to functionalize up to 27% of the styrene units with piperidine rings and subsequently achieve complete quaternization. The synthetic approach ensures that all of the sensitive β-hydrogens of the cations are present in ring structures to provide high stability. AEMs based on these polymers show high alk. stability and less than 5% ionic loss was observed by 1H NMR spectroscopy after 30 days in 2 M aqueous NaOH at 90°C. AEMs functionalized with N,N-di-Me piperidinium cations show higher stability than the ones carrying N-spirocyclic quaternary ammonium. Careful anal. of the latter revealed that the rings formed in the cyclo-quaternization are more prone to degrade via Hofmann elimination than the rings introduced in the Friedel-Crafts reaction. AEMs with an ion-exchange capacity of 1.5 mequiv g-1 reach a hydroxide conductivity of 106 mS cm-1 at 80°C under fully hydrated conditions. The AEMs are further tuned and improved by blending with polybenzimidazole (PBI). For example, an AEM containing 2 weight % PBI shows reduced water uptake and much improved robustness during handling and reaches 71 mS cm-1 at 80°C. The study demonstrates that the critical alk. stability of PS-containing AEMs can be significantly enhanced by replacing the benchmark benzyltrimethyl ammonium cations with N-alicyclic piperidine-based cations.
There is still a lot of research devoted to this compound(SMILES：BrCCCCCBr)SDS of cas: 111-24-0, and with the development of science, more effects of this compound(111-24-0) can be discovered.
Reference:
Chiral nitrogen ligands in late transition metal-catalysed asymmetric synthesis—I. Addressing the problem of ligand lability in rhodium-catalysed hydrosilations,
Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis