Gas‐Phase Models for the Nickel‐ and Palladium‐Catalyzed Deoxygenation of Fatty Acids
Gas‐Phase Models for the Nickel‐ and Palladium‐Catalyzed Deoxygenation of Fatty Acids
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DOI：
10.1002/cctc.202000908
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发表时间：
2020-09
期刊：
影响因子：
4.5
通讯作者：
K. Parker;Geethika K. Weragoda;V. Pho;A. Canty;Anastasios Polyzos;R. O'hair;V. Ryzhov
中科院分区：
文献类型：
--
作者：
K. Parker;Geethika K. Weragoda;V. Pho;A. Canty;Anastasios Polyzos;R. O'hair;V. Ryzhov
使用脂肪酸作为生物燃料的可再生来源需要脱氧。虽然已经开发了许多有前途的催化剂来实现这一目标，但对其操作机制知之甚少。在这里，模型分子系统的研究在气相中使用质谱实验和DFT计算。通过电喷雾电离形成配位金属配合物[（phen）M（O2 CR）]+（其中phen= 1，10-菲咯啉; M=Ni或Pd; R= CnH 2n +1，n≥2）。它们的碰撞诱导解离（CID）通过损失CO2和[C，H2，O2]启动脱氧。硬脂酸酯络合物（R= C17 H35）的CID谱也显示一系列阳离子[（phen）M（R '）]+（其中R' C2）对这些羧酸不反应。DFT计算与这些结果一致，并揭示了羧酸对“自由”配位位点的接近被R > CH 3的agostic相互作用阻断。
Using fatty acids as renewable sources of biofuels requires deoxygenation. While a number of promising catalysts have been developed to achieve this, their operating mechanisms are poorly understood. Here, model molecular systems are studied in the gas phase using mass spectrometry experiments and DFT calculations. The coordinated metal complexes [(phen)M(O2CR)]+ (where phen=1,10‐phenanthroline; M=Ni or Pd; R=CnH2n+1, n≥2) are formed via electrospray ionization. Their collision‐induced dissociation (CID) initiates deoxygenation via loss of CO2 and [C,H2,O2]. The CID spectrum of the stearate complexes (R=C17H35) also shows a series of cations [(phen)M(R’)]+ (where R’ C2), were unreactive towards these carboxylic acids. DFT calculations are consistent with these results and reveal that the approach of the carboxylic acid to the “free” coordination site is blocked by agostic interactions for R > CH3.