Universidade de Franca, Franca-SP, Brazil.
ACS Appl Mater Interfaces. 2009 Nov;1(11):2667-78. doi: 10.1021/am900556b.
The preparation, characterization, and application in oxidation reactions of new biomimetic catalysts are reported. Brazilian Sao Simao kaolinite clay has been functionalized with [meso-tetrakis(pentafluorophenyl)porphinato]iron(III), Fe(TPFPP). To obtain the functionalized clay, the natural clay was purified by dispersion-sedimentation, expanded by insertion of dimethyl sulfoxide (DMSO), and functionalized with amino groups by substitution of DMSO with ethanolamine. These previous steps allowed clay functionalization with Fe(TPFPP), leading to a layered material with a basal spacing of 10.73 A. Clay functionalization with the porphyrin was confirmed by formation of the secondary amine, as demonstrated by FTIR bands at 3500-3700 cm(-1). UV-vis spectroscopy revealed a red shift in the Soret band of the iron porphyrin in the functionalized material as compared to the parent iron porphyrin catalyst in solution, indicating Fe(III)P --> Fe(II)P reduction. The catalytic performance of the functionalized clay was evaluated in the epoxidation of cyclooctene, with complete selectivity for the epoxide (100% epoxide yield), and ketonization of cyclohexane, cyclohexanone being the major product. The novel catalyst was also evaluated in the Baeyer-Villiger (BV) oxidation of cyclohexanone, with 85% conversion of cyclohexanone in epsilon-caprolactone, with total selectivity to epsilon-caprolactone.
本文报道了新型仿生催化剂的制备、表征及其在氧化反应中的应用。巴西圣西蒙高岭土已用 [meso-四（五氟苯基）卟啉基] 铁（III），Fe（TPFPP）进行功能化。为了获得功能化的粘土，天然粘土通过分散-沉降进行纯化，用二甲基亚砜（DMSO）插入进行膨胀，并用乙醇胺取代 DMSO 进行氨基取代进行功能化。这些先前的步骤允许粘土与 Fe（TPFPP）进行功能化，导致层状材料的基面间距为 10.73 A。通过形成仲胺，证实了粘土与卟啉的功能化，如在 3500-3700 cm（-1）处的 FTIR 带所示。紫外可见光谱显示，与溶液中母体铁卟啉催化剂相比，功能化材料中铁卟啉的 Soret 带发生红移，表明 Fe（III）P --> Fe（II）P 还原。功能化粘土的催化性能在环辛烯的环氧化中进行了评估，具有环氧化物的完全选择性（100%环氧化物收率），以及环己烷的酮化，环己酮是主要产物。新型催化剂还在环己酮的 Baeyer-Villiger（BV）氧化中进行了评估，在 ε-己内酯中环己酮的转化率为 85%，ε-己内酯的总选择性为 100%。
