18-Crown-6 (CAS 17455-13-9) is a macrocyclic polyether and potassium-selective ionophore with 99% purity. Its cavity diameter of 2.6-3.2 Å is matched to the K+ ionic radius of 2.76 Å, exhibiting a log Ka = 6.08 for K+ in methanol—the highest selectivity among common crown ethers for potassium. S.Nihar Exports, an ISO 9001:2015 certified supplier, provides 18-Crown-6 with a Certificate of Analysis.
Properties and Selectivity
18-Crown-6 (CAS 17455-13-9) is characterized as a macrocyclic polyether with a cavity diameter ranging from 2.6 to 3.2 Å. This size is specifically matched to the K+ ionic radius of 2.76 Å, making it a highly effective potassium-selective ionophore. Its association constant for K+ in methanol, log Ka = 6.08, represents the highest selectivity for potassium among common crown ethers. The compound is supplied with 99% purity.
Key Applications and End-Uses
18-Crown-6 finds extensive application across various fields:
- Phase-Transfer Catalysis: Widely used to transport potassium salts into the organic phase, enabling reactions in aprotic solvents. This includes the activation of KF, KOH, and KMnO4 under anhydrous conditions.
- Potassium-Selective Electrodes (ISE): It serves as a standard ionophore in electrodes designed for clinical blood analysis (measuring K+ levels) and environmental monitoring.
- Green Chemistry: Facilitates reactions without the need for polar aprotic solvents, contributing to more sustainable chemical processes.
- Supramolecular Chemistry Research: Utilized in host-guest complexation studies.
- Organic Oxidations: Activates potassium permanganate in organic oxidation reactions.
Sourcing 18-Crown-6 from S.Nihar Exports
S.Nihar Exports, an ISO 9001:2015 certified fine and specialty chemical supplier, offers 18-Crown-6. Headquartered in Mumbai, India (512 Maker Bhavan 3, New Marine Lines, Mumbai 400020), the company was founded in 1995 and is part of N. Himatlal & Co. Every shipment includes a Certificate of Analysis (COA). HPLC-grade, ACS reagent, and indicator-grade variants of 18-Crown-6 are available upon request.