A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 179474-79-4, Name is 1-(3-Methoxypropyl)piperidin-4-amine, molecular formula is C9H20N2O. In an article, author is Olsson, Joel S.,once mentioned of 179474-79-4, Product Details of 179474-79-4.
Functionalizing Polystyrene with N-Alicyclic Piperidine-Based Cations via Friedel-Crafts Alkylation for Highly Alkali-Stable Anion-Exchange Membranes
Different anion-exchange membranes (AEMs) based on polystyrene (PS)-carrying benzyltrimethyl ammonium cations are currently being developed for use in alkaline 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-dimethyl piperidinium cations or by cyclo-quaternizations using 1,5-dibromopentane and 1,4-dibromobutane, respectively, 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 beta-hydrogens of the cations are present in ring structures to provide high stability. AEMs based on these polymers show high alkaline stability and less than 5% ionic loss was observed by H-1 NMR spectroscopy after 30 days in 2 M aq NaOH at 90 degrees C. AEMs functionalized with N,N-dimethyl piperidinium cations show higher stability than the ones carrying N-spirocyclic quaternary ammonium. Careful analysis 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 degrees C under fully hydrated conditions. The AEMs are further tuned and improved by blending with polybenzimidazole (PBI). For example, an AEM containing 2 wt % PBI shows reduced water uptake and much improved robustness during handling and reaches 71 mS cm(-1) at 80 degrees C. The study demonstrates that the critical alkaline stability of PS-containing AEMs can be significantly enhanced by replacing the benchmark benzyltrimethyl ammonium cations with N-alicyclic piperidine-based cations.
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Reference:
Piperidine – Wikipedia,
,Piperidine | C5H11N – PubChem