Kaikake Katsuya, Takada Masafumi, Soma Daiki, Jin Ren-Hua
Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University 3-27-1, Rokkakubashi, Kanagawa-ku Yokohama 221-8686 Japan
RSC Adv. 2018 Oct 8;8(60):34505-34513. doi: 10.1039/c8ra06476h. eCollection 2018 Oct 4.
Polystyrenic microspheres in the sub 5 micrometer size range (micro-gel) with -CHCl active sites were synthesized the dispersion polymerization of 4-chloromethylstyrene, divinyl benzene and methoxy polyethylene glycol acrylate. Then, theophylline residues were introduced onto the polystyrenic microspheres the substitution of the chloride in the -CHCl group to prepare chelate type microspheres of μ-T2. It was found that the microspheres have co-continuous structures, monodispersed particle sizes, and excellent solvent and water wettability. Using the μ-T2 microspheres possessing theophylline residues, adsorption experiments involving the adsorption of palladium(ii), copper(ii) and platinum(iv) from acidic chloride media under both individual and mixed conditions were carried out and it was found that the μ-T2 microspheres exhibited excellent adsorption selectivity for palladium(ii) over copper(ii) and platinum(iv). It was also revealed that thiourea or ammonia solutions are the most effective in desorbing palladium ions from the microspheres. Despite being used in four adsorption-desorption cycles, the μ-T2 microspheres were still able to strongly adsorb palladium ions, with an adsorption of over 85%. In addition, the μ-T2 microspheres also showed palladium capturing ability even in very dilute palladium solutions (below 1.0 ppm). Interestingly, the μ-T2 microsphere-adsorbed palladium ions exhibited excellent catalytic activity in the Suzuki-Miyaura coupling reaction of bromobenzene and phenylboronic acid, yielding biphenyl in 100% under the conditions within 1 hour at 50 °C in water.
通过4-氯甲基苯乙烯、二乙烯基苯和甲氧基聚乙二醇丙烯酸酯的分散聚合反应，合成了尺寸小于5微米的带有-CHCl活性位点的聚苯乙烯微球（微凝胶）。然后，通过-CHCl基团中氯的取代反应，将茶碱残基引入到聚苯乙烯微球上，制备了μ-T2螯合型微球。研究发现，这些微球具有共连续结构、单分散粒径以及优异的溶剂和水润湿性。使用含有茶碱残基的μ-T2微球，在单独和混合条件下进行了从酸性氯化物介质中吸附钯（II）、铜（II）和铂（IV）的吸附实验，结果发现μ-T2微球对钯（II）表现出优于铜（II）和铂（IV）的优异吸附选择性。还发现硫脲或氨溶液在从微球上解吸钯离子方面最有效。尽管经过四个吸附-解吸循环，μ-T2微球仍能强烈吸附钯离子，吸附率超过85%。此外，即使在非常稀的钯溶液（低于1.0 ppm）中，μ-T2微球也表现出钯捕获能力。有趣的是，μ-T2微球吸附的钯离子在溴苯和苯硼酸的铃木-宫浦偶联反应中表现出优异的催化活性，在50℃水中1小时的条件下，联苯产率为100%。
