The author of 《Mechanism of ε-caprolactone polymerization in the presence of alkali metal salts: investigation of initiation course and determination of polymers structure by MALDI-TOF mass spectrometry》 were Grobelny, Zbigniew; Golba, Sylwia; Jurek-Suliga, Justyna. And the article was published in Polymer Bulletin (Heidelberg, Germany) in 2019. Quality Control of 1,4,7,10,13-Pentaoxacyclopentadecane The author mentioned the following in the article:
Various alkali metal salts were applied as initiators for ε-caprolactone anionic ring-opening polymerization in THF at room temperature It was observed that potassium methoxide (MeOK), potassium isopropoxide (i-PrOK) and potassium tert-butoxide (t-BuOK) nonactivated or activated by 18-crown-6 (18C6) initiated polymerization mainly by deprotonation of the monomer. In the case of potassium hydride (KH), its basicity increased with the ability of the ligand for cation complexation. For example, KH without ligand or with weak ligands for K+ as 12C4 reacted exclusively by ring opening. However, in the presence of strong ligands, as 15C5, 18C6 or cryptand C222, basicity of H- increased with the ability of the ligand for cation complexation. In the last case, ∼ 32% of the monomer was deprotonated. In these systems, gaseous H2 evolved during the initiation. Deprotonation of the monomer by some initiators resulted in macromols. with reactive aldehyde group or lactone ring as starting groups. They took part in the reaction with potassium alkoxide active centers of growing chains leading to the formation of branched poly(ε-caprolactone)s. Sodium hydride (NaH) was inactive, but in the presence of 15-crown-5 or 18-crown-6 initiated polymerization exclusively by ring opening. MALDI-TOF mass spectrometry supported with 13C NMR and SEC was used for anal. of the polymers obtained. Mechanism of the studied processes was proposed and discussed. The experimental part of the paper was very detailed, including the reaction process of 1,4,7,10,13-Pentaoxacyclopentadecane(cas: 33100-27-5Quality Control of 1,4,7,10,13-Pentaoxacyclopentadecane)
1,4,7,10,13-Pentaoxacyclopentadecane(cas: 33100-27-5) is a member of crown ether Ligands. Crown-ethers are macrocyclic polyethers capable of forming host-guest complexes, especially with inorganic and organic cations. Crown-ethers can incorporate protonated primary amine compounds by formation of ion-dipole bonds with the oxygen atoms of the chiral selector. Crown-ethers have been widely used for the separation of several pharmaceuticals both in aqueous and non-aqueous media. Quality Control of 1,4,7,10,13-Pentaoxacyclopentadecane
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem