Oxidative Polymerization Reaction Research Articles

Role of silicon in polymer synthesis: activation of the oxidative coupling of thiophene by trimethylsilyl substituents; a route to high molecular weight poly(3-alkyl)thiophene

The role of silyl substituents in the anodic polymerization of thiophene has been studied. The oxidative polymerization reaction is activated by the presence of trimethylsilyl groups. In order to obtain polymer of high molecular weight and low polydispersity, two such trimethylsilyl substituents in the 2,5-positions of the thiophene ring were found to be necessary.

Molecular spectrometric studies of complexes copper-pyridine catalysts of the oxidative coupling of phenols—I. Electronic and EPR studies of the catalytic complex

The EPR and optical spectra of compounds copper(I) chloride—pyridine-O 2, catalysts of the oxidative coupling polymerization reaction of 2,6 dimethyl phenol have been investigated. Analysis of the e.p.r. spectra indicate that, for active complexes in solution, the sigma bonding is appreciable covalent. A program relating the electronic and magnetic properties has shown that these complexes are varying from tetragonally elongated octahedrons, the ground state being d x 2– y 2 , to nearly square planar arrangement (negligible axial coordination). In the solid state, the complexes would be orthorhombic. In all cases, the active species would present CuO bonds.

Oxidative polymerization of aromatic hydrocarbons: A study of kinetics and mechanism

AbstractAromatic hydrocarbons were homopolymerized by means of an oxidative polymerization reaction with the use of the catalyst system anhydrous aluminum chloride–cupric chloride. The kinetics of the benzene homopolymerization carried out under different experimental conditions was followed by the determination of the amounts of cuprous ion and polymeric product formed in the reaction. Cuprous ion was spectrophotometrically titrated in the form of its complex with 2,2′‐biquinolyl (cuproine). The experimental results do not agree with cationic mechanism for this reaction previously proposed in the literature. Ethylbenzene was kinetically studied under the same experimental conditions. In view of the experimental evidences obtained in this work and on some literature data, a mechanism based on formation of cation‐radicals is proposed for the oxidative polymerization reaction when carried out under the studied conditions.

The oxidative coupling polymerization of 2.6‐dimethylphenol with basic copper(II) chloride‐pyridine complex

AbstractThe results of the investigation on the oxidative coupling polymerization reaction of 2.6‐dimethylphenol in the presence of copper(II) chloride‐pyridine‐KOH complex (basic copper(II) complex) are reported. The yield of poly(2.6‐dimethyl‐4.4′‐phenylene oxide) which is the CO coupling product closely depends upon the copper(II) chloride concentration, the ratio of pyridine/copper(II) chloride, and the ratio of KOH/copper(II) chloride. However, the yield of 3.3′.5.5′‐tetramethyl‐4.4′‐diphenoquinone, the CC coupling product, scarcely changes with these reaction conditions.The rate of polymerization of 2.6‐dimethylphenol under oxygen was much larger than that determined in an air atmosphere.The basic copper(II) chloride complex catalyst showed the unusual property that the electron spin resonance‐detectable copper(II) ion in the basic copper(II) chloride complex was only 35 ± 5% using pure copper(II) chloride‐pyridine complex not containing KOH as a standard.It has been found by means of ESR measurements that the basic copper(II) complex had the function of an one‐electron transfer reagent.

Oxidative Polymerization of Polybutadiene and Its Derivatives

Abstract The oxidative polymerization or peroxide curing for such prepolymers as polybutadiene consisting mainly of 1, 2-structure, or esters containing the butadiene units was studied by means of infrared spectral analysis and dynamic mechanical measurements. Films of the cross-linked polybutadiene formed by the oxidative polymerization reaction show a high glass transition temperature and a high degree of crosslinking. This is considered to be the result of the larger amount of double bonds that are involved in the prepolymers and which suffer cross-linking, and the result of the presence of such polar groups as those of carboxyl, carbonyl and hydroxyl groups in the dried film, which are formed in the course of oxidative polymerization. When t-butylperbenzoate was used as a catalyst for cross-linking polybutadiene, some cyclization of vinyl groups was observed, leading to a less effective cross-linking. A greater reactivity was observed for trans-ethylenic double bonds than for vinyl groups in these reactions. Polybutadiene, being of larger molecular weight, gave a film of a higher (Tg)d value.