A Highly Efficient Aromatic Amine Ligand/Copper(I) Chloride Catalyst System for the Synthesis of Poly(2,6-dimethyl-1,4-phenylene ether)

• Published in: Polymers Vol. 10; no. 4; p. 350
• Main Authors: Kim, Kisoo, Shin, Min Jae, Kim, Yong Tae, Kim, Joong-In, Kim, Young Jun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22-03-2018; MDPI
• Subjects: Basicity; Catalysis; Catalysts; Chemical synthesis; Chloroform; Copper; Ligands; Polymerization; Steric hindrance; 3,3′,5,5′-tetramethyl-4,4′diphenoquinone; rate of polymerization; poly(2,6-dimethyl-1,4-phenylene ether); aromatic amine ligand; highly effective catalyst; copper(I) chloride
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym10040350

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,
/
) 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',5,5'-Tetramethyl-4,4'diphenoquinone (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 × 10
mol/L·s 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.