{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,18]],"date-time":"2026-01-18T12:53:23Z","timestamp":1768740803773,"version":"3.49.0"},"reference-count":31,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2018,3,22]],"date-time":"2018-03-22T00:00:00Z","timestamp":1521676800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Highly active catalyst systems for polymerizing 2,6-dimethylphenol were studied by using aromatic amine ligands and copper(I) chloride. The aromatic amine ligands employed were pyridine, 1-methylimidazole, 2-aminopyridine, 3-aminopyridine, and 4-aminopyridine. A mixture of chloroform and methanol (9:1, v\/v) was used as a polymerization solvent. All experiments were performed with oxygen uptake measurement apparatus, while the reaction rate for each aromatic amine ligand-Cu catalyst system and the amount of by-product, 3,3\u2032,5,5\u2032-Tetramethyl-4,4\u2032diphenoquinone (DPQ), were measured to determine the efficiency of the catalyst systems. The 4-aminopyridine\/Cu (I) catalyst system was found to be extremely efficient in poly(2,6-dimethyl-1,4-phenylene ether) (PPE) synthesis; it had the fastest reaction rate of 6.98 \u00d7 10\u22124 mol\/L\u00b7s and the lowest DPQ production. The relatively high basicity of 4-aminopyridne and the less steric hindrance arising from a coordination of Cu and 4-aminopyridine in this catalyst are responsible for the fast polymerization rate. When 2-aminoprydine (an isomer of 4-aminopyridine) was used as a ligand, however, no polymerization occurred probably due to steric hindrance.<\/jats:p>","DOI":"10.3390\/polym10040350","type":"journal-article","created":{"date-parts":[[2018,3,22]],"date-time":"2018-03-22T05:14:55Z","timestamp":1521695695000},"page":"350","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["A Highly Efficient Aromatic Amine Ligand\/Copper(I) Chloride Catalyst System for the Synthesis of Poly(2,6-dimethyl-1,4-phenylene ether)"],"prefix":"10.3390","volume":"10","author":[{"given":"Kisoo","family":"Kim","sequence":"first","affiliation":[{"name":"School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea"},{"name":"Hyosung R&amp;D Business Labs, 74 Simin-daero, Dongan-gu, Anyang-si 14080, Gyunggi-do, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Min","family":"Shin","sequence":"additional","affiliation":[{"name":"School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea"},{"name":"LG Household &amp; Health Care R&amp;D Center, LG Science Park, Magok, Kangseo-go, Seoul 07795, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yong","family":"Kim","sequence":"additional","affiliation":[{"name":"SAMSUNG SDI, SDI-dong, Maetan-dong 130, Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 16678, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joong-In","family":"Kim","sequence":"additional","affiliation":[{"name":"Hyosung R&amp;D Business Labs, 74 Simin-daero, Dongan-gu, Anyang-si, Gyunggi-do 14080, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8859-1826","authenticated-orcid":false,"given":"Young","family":"Kim","sequence":"additional","affiliation":[{"name":"School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon-si, Gyeonggi-do 16419, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,3,22]]},"reference":[{"key":"ref_1","first-page":"15","article-title":"Poly(phenylene oxide)","volume":"Volume 3","author":"Thomas","year":"2011","journal-title":"Handbook of Engineering and Specialty Thermoplastics"},{"key":"ref_2","first-page":"1141","article-title":"Thermodynamic properties of poly(2,6-dimethyl-1,4-phenylene ether)","volume":"6","author":"Karasz","year":"1968","journal-title":"J. Polym. Sci. Part B"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1177\/0734904115595993","article-title":"Characterization of compatibilized blends of nylon 66\/poly(2,6-dimethyl-1,4-phenylene ether)\/high-impact polystyrene filled with phosphinate-based flame retardants: Mechanical property, rheological behavior, and flame retardancy","volume":"33","author":"Kim","year":"2015","journal-title":"J. Fire Sci."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.polymer.2015.04.016","article-title":"Tg and Tg breadth of poly(2,6-dimethyl-1,4-phenylene oxide)\/polystyrene miscible polymer blends characterized by differential scanning calorimetry, ellipsometry, and fluorescence spectroscopy","volume":"65","author":"Jin","year":"2015","journal-title":"Polymer"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.polymer.2015.12.055","article-title":"Influence of carbon nanotubes localization and transfer on electrical conductivity in PA66\/(PS\/PPE)\/CNTs nanocomposites","volume":"84","author":"Lee","year":"2016","journal-title":"Polymer"},{"key":"ref_6","unstructured":"Li, Y.F., Meng, J., and Zou, X.D. (2008). Flame Retardant Thermoplastic Composition Useful For Laser Direct Structuring. (20130289178 A1), U.S. Patent."},{"key":"ref_7","first-page":"1333","article-title":"Poly(phenylene Oxide)","volume":"Volume 3","author":"Wilks","year":"2001","journal-title":"Industrial Polymers Handbook: Products, Processes, Applications"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1021\/ma60007a022","article-title":"Poly(2,6-diphenyl-1,4-phenylene oxide)","volume":"2","author":"Hay","year":"1969","journal-title":"Macromolecules"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2174","DOI":"10.1002\/app.34322","article-title":"Oxidative polymerization of 2,6-dimethylphenol in water using bis-triazacyclononane copper catalyst","volume":"122","author":"Saito","year":"2011","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_10","unstructured":"Aubel, P.G. (2002). Various Aspects of Copper-Catalysed Oxidative Coupling Reaction of 2,6-Dimethylphenol. [Ph.D. Thesis, Universiteit Leiden]."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"12590","DOI":"10.1021\/ja971612v","article-title":"Ab Initio calculations on 2,6-dimethylphenol and 4-(2,6-dimethylphenoxy)-2,6-dimethylphenol. Evidence of an important role for the phenoxonium cation in the copper-catalyzed oxidative phenol coupling reaction","volume":"119","author":"Baesjou","year":"1997","journal-title":"J. Am. Chem. Soc."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1142\/S0256767909004229","article-title":"Oxidative polymerization behavior of 2,6-dimethylphenol in aqueous media with potassium ferricyanide","volume":"27","author":"Gu","year":"2009","journal-title":"Chin. J. Polym. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"6581","DOI":"10.1016\/j.polymer.2006.07.033","article-title":"Catalyzed oxidative polymerization to form poly(2,6-dimethyl-1,4-phenylene oxide) in water using water-soluble copper complex","volume":"47","author":"Saito","year":"2006","journal-title":"Polymer"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1016\/j.crci.2012.11.011","article-title":"Carboxylic-supported copper complexes as catalyst for the green oxidative coupling of 2,6-dimethylphenol: Synthesis, characterization and structure","volume":"16","author":"Liu","year":"2013","journal-title":"Comptes Rendus Chim."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1007\/s00289-012-0816-9","article-title":"Synthesis of poly(2,6-dimethyl-1,4-phenylene ether) with controlled molecular weight via suspension polymerization catalyzed by amine\u2013copper (I) complexes under various reaction conditions","volume":"70","author":"Kim","year":"2013","journal-title":"Polym. Bull."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2326","DOI":"10.3390\/molecules13092326","article-title":"Imidazole-based Potential Bi- and Tridentate Nitrogen Ligands: Synthesis, Characterization and Application in Asymmetric Catalysis","volume":"13","author":"Sivek","year":"2008","journal-title":"Molecules"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"3982","DOI":"10.1021\/ma00014a002","article-title":"Studies on immobilized polymer-bound imidazole-copper (II) complexes as catalysts. 3. Immobilization of copper (II) complexes of poly(styrene-co-N-vinylimidazole) by grafting on silica and their catalysis of oxidative coupling of 2,6-disubstituted phenols","volume":"24","author":"Wei","year":"1991","journal-title":"Macromolecules"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1318","DOI":"10.1021\/ma00207a016","article-title":"Carbon-13 NMR study of poly(2,6-dimethyl-1,4-phenylene oxide)s. Sites of amine incorporation","volume":"23","author":"White","year":"1990","journal-title":"Macromolecules"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1107","DOI":"10.1021\/ie00029a006","article-title":"Polymerization of 2,6-dimethylphenol with mixed-ligand copper complexes","volume":"33","author":"Li","year":"1994","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"5684","DOI":"10.1016\/j.polymer.2013.08.023","article-title":"Synthesis of poly(2,6-dimethyl-1,4-phenylene oxide) derivatives in water using water-soluble copper complex catalyst with natural ligands","volume":"54","author":"Chen","year":"2013","journal-title":"Polymer"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1016\/1381-1169(96)00065-9","article-title":"A kinetic and spectroscopic study on the copper catalyzed oxidative coupling polymerization of 2,6-dimethylphenol. X-ray structure of the catalyst precursor tetrakis (N-methylimidazole) bis(nitrato) copper(II)","volume":"110","author":"Baesjou","year":"1996","journal-title":"J. Mol. Catal. A Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"148","DOI":"10.1021\/ja01534a040","article-title":"Imidazole Catalysis II The Reaction of substituted imidazoles with phenyl acetates in aqueous solution","volume":"80","author":"Bruice","year":"1958","journal-title":"J. Am. Chem. Soc."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Angyal, S.J., and Angyal, C.L. (1952). The tautomerism of N-hetero-aromatic amines. Part I. J. Chem. Soc., 1461\u20131466.","DOI":"10.1039\/jr9520001461"},{"key":"ref_24","unstructured":"(2017, August 10). pKa Data Compiled by R. Williams. Available online: https:\/\/www.chem.wisc.edu\/areas\/reich\/pkatable\/pKa_compilation-1-Williams.pdf."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1293","DOI":"10.1016\/S0014-3057(00)00259-7","article-title":"A spectacular increase in the polymerization rate of 2,6-dimethylphenol induced by acetonitrile","volume":"37","author":"Gamez","year":"2001","journal-title":"Eur. Polym. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1158","DOI":"10.1039\/C1DT11065A","article-title":"Efficient oxidative coupling of 2,6-disubstituted phenol catalyzed by a dicopper (II) complex","volume":"41","author":"Liao","year":"2012","journal-title":"Dalton Trans."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"970","DOI":"10.5059\/yukigoseikyokaishi.63.970","article-title":"Radical-controlled oxidative polymerization of phenols","volume":"63","author":"Hideyuki","year":"2005","journal-title":"J. Synth. Org. Chem. Jpn."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1002\/macp.1972.021510117","article-title":"The kinetics of the oxidative polymerization of 2.6-xylenol with a copper-amine complex","volume":"151","author":"Uchidma","year":"1972","journal-title":"Makromol. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1002\/(SICI)1099-0518(199803)36:4<505::AID-POLA1>3.0.CO;2-O","article-title":"Polymerization by oxidative coupling: Discovery and commercialization of PPO\u00ae and Noryl\u00ae resins","volume":"36","author":"Hay","year":"1998","journal-title":"J. Polym. Sci. Part A Polym. Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1080","DOI":"10.1016\/j.eurpolymj.2009.01.012","article-title":"The initial oxidative polymerization kinetics of 2,6-dimethylphenol with a Cu\u2013EDTA complex in water","volume":"45","author":"Liu","year":"2009","journal-title":"Eur. Polym. J."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1015","DOI":"10.1016\/S0079-6700(03)00014-5","article-title":"Oxidative polymerization of phenols revisited","volume":"28","author":"Kobayashi","year":"2003","journal-title":"Prog. Polym. Sci."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/10\/4\/350\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T14:58:04Z","timestamp":1760194684000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/10\/4\/350"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,3,22]]},"references-count":31,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2018,4]]}},"alternative-id":["polym10040350"],"URL":"https:\/\/doi.org\/10.3390\/polym10040350","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,3,22]]}}}