Journal of Nanoparticle Research ( IF 2.5 ) Pub Date : 2020-06-12 , DOI: 10.1007/s11051-020-04904-9 Tingting Sun , Huazhe Liang , Shaojie Liu , Erjun Tang , Cuiyan Fu
Magnetic nanoparticles (MNPs) modified by polyamidoamine (PAMAM)-immobilized 2,2,6,6-tetramethyl-1-piperidinyl-oxyl (TEMPO) as recoverable catalysts for catalytic oxidation of polyethylene glycol were designed and prepared, which were expected to combine the advantages of easy recovery of MNPs and high activity of PAMAM-immobilized TEMPO. The catalysts of MNPs modified by PAMAM-immobilized TEMPO (MNPs-PAMAM-T) were characterized by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analyzer (TGA), and transmission electron microscopy (TEM). The mean particle size of MNPs was about 10 nm. MNPs-PAMAM-T/NaBr/NaClO was used as catalytic system for catalytic oxidation of monomethoxy poly (ethylene glycol). The catalytic performances were affected by the loading amounts of TEMPO and PAMAM generations. It was shown that the catalyst with TEMPO loading of 5.198 mmol/g using G2.0 PAMAM-modified MNPs as carrier had the best catalytic performance, which could be up to 94% of the free TEMPO level. The efficient recovery of catalyst could be achieved by magnetic separation and the recycling performance was good.
中文翻译:
固定有聚酰胺基胺的TEMPO修饰的磁性纳米粒子用于单甲氧基聚(乙二醇)的催化氧化
设计并制备了以聚酰胺酰胺(PAMAM)固定化的2,2,6,6-四甲基-1-哌啶基-氧基(TEMPO)修饰的磁性纳米粒子(MNP)作为可回收的聚乙二醇催化氧化催化剂,有望结合使用MNPs易于回收和PAMAM固定的TEMPO高活性的优点。通过傅立叶变换红外光谱(FT-IR),热重分析仪(TGA)和透射电子显微镜(TEM)对固定有PAMAM的TEMPO修饰的MNP的催化剂(MNPs-PAMAM-T)进行了表征。MNP的平均粒径为约10nm。MNPs-PAMAM-T / NaBr / NaClO用作单甲氧基聚乙二醇催化氧化的催化体系。催化性能受TEMPO和PAMAM世代的负载量影响。结果表明,以G2.0 PAMAM修饰的MNPs为载体,TEMPO负载量为5.198 mmol / g的催化剂具有最佳的催化性能,最高可达游离TEMPO含量的94%。通过磁选可以实现催化剂的有效回收,回收性能良好。