Amorati Riccardo, Guo Yafang, Budhlall Bridgette Maria, Barry Carol Forance, Cao Dongmei, Challa Siva Sai Ramana Kumar
Department of Chemistry "G. Ciamician", University of Bologna, Via Gobetti 83, 40129 Bologna, Italy.
Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, Massachusetts 01854, United States.
ACS Omega. 2023 Oct 18;8(43):40174-40183. doi: 10.1021/acsomega.3c03654. eCollection 2023 Oct 31.
The use of nanomaterials as inhibitors of the autoxidation of organic materials is attracting tremendous interest in petrochemistry, food storage, and biomedical applications. Metal oxide materials and CeO in particular represent one of the most investigated inorganic materials with promising radical trapping and antioxidant abilities. However, despite the importance, examples of the CeO material's ability to retard the autoxidation of organic substrates are still lacking, together with a plausible chemical mechanism for radical trapping. Herein, we report the synthesis of a new CeO-derived nanoporous material (NCeONP) with excellent autoxidation inhibiting properties due to its ability to catalyze the cross-dismutation of alkyl peroxyl (ROO) and hydroperoxyl (HOO) radicals, generated in the system by the addition of the pro-aromatic hydrocarbon γ-terpinene. The antioxidant ability of NCeONP is superior to that of other nanosized metal oxides, including TiO, ZnO, ZrO, and pristine CeO nanoparticles. Studies of the reaction with a sacrificial reductant allowed us to propose a mechanism of inhibition consisting of H atom transfer from HOO to the metal oxides (MO + HOO → MO-H + O), followed by the release of the H atom to an ROO radical (MO-H + ROO → MO + ROOH). Besides identifying NCeONP as a promising material for developing effective antioxidants, our study provides the first evidence of a radical mechanism that can be exploited to develop novel solid-state autoxidation inhibitors.
在石油化学、食品储存和生物医学应用领域，将纳米材料用作有机材料自氧化的抑制剂正引起人们极大的兴趣。金属氧化物材料，尤其是CeO，是研究最多的具有自由基捕获和抗氧化能力的无机材料之一。然而，尽管其很重要，但仍缺乏CeO材料抑制有机底物自氧化能力的实例，以及自由基捕获的合理化学机制。在此，我们报道了一种新型CeO衍生的纳米多孔材料（NCeONP）的合成，该材料具有优异的自氧化抑制性能，因为它能够催化由添加前体芳烃γ-萜品烯在体系中产生的烷基过氧自由基（ROO）和氢过氧自由基（HOO）的交叉歧化反应。NCeONP的抗氧化能力优于其他纳米尺寸的金属氧化物，包括TiO、ZnO、ZrO和原始CeO纳米颗粒。与牺牲性还原剂的反应研究使我们能够提出一种抑制机制，该机制包括H原子从HOO转移到金属氧化物（MO + HOO → MO-H + O），随后H原子释放到ROO自由基上（MO-H + ROO → MO + ROOH）。除了将NCeONP确定为开发有效抗氧化剂的有前景的材料外，我们的研究还首次提供了一种自由基机制的证据，该机制可用于开发新型固态自氧化抑制剂。
