Zehao Han,Lun Pan,Kang Xue,Jisheng Xu,Qing Liu,Ying Xu,Zhouyang Shen,Xiangwen Zhang,Ji-Jun Zou
Polycyclic alkanes are not only the important components of high-density fuels, but also can be used to cool the overheating parts of hypersonic vehicle through catalytic endothermic dehydrogenation reaction. However, the dehydrogenation performances of cycloalkanes with different molecule structures vary widely. Herein, we investigated the effects of cycloalkane structures, including the length of branched chains, the number of branched chains, the number of rings, and the shape of rings, on the dehydrogenation performance. The results show that cyclohexane (CH) exhibits the best dehydrogenation performance (600 °C, 3 MPa) with >99% conversion, >99% benzene selectivity, and highest total heat sink of 4.47 MJ/kg. The branched chains, ring number and five-membered rings all have negative effects on dehydrogenation. Among them, the number of rings has the minimum negative impact. Moreover, we correlated the density, volumetric net heat of combustion (NHOC) and heat sink with the molecular structure of the cyclic alkanes and found that the polycyclic alkanes with low H/C ratio and high M have both high density, high volumetric NHOC and high heat sink. This work can provide guidance for development and design of advanced fuels for endothermic dehydrogenation.
Xiao Kuang,Yuting Hu,Dongxu Chi,Haolin Zhang,Zhonggui He,Yiguo Jiang,Yongjun Wang
A surge of platinum(IV) compounds are utilized or investigated in cancer treatment but their therapeutic outcomes have been greatly compromised by remaining adverse effects and limited antitumor performance, attributable to nonspecific distribution and insufficient activation in tumor site. Herein, we designed a series of disulfide bond introduced Pt(IV)-lipid prodrugs with different branch length, all of which are able to self-stabilize into nanomedicine and be activated by high intracellular glutathione (GSH) level. The impact of precise modification of these prodrugs on their assembly stability, pharmacokinetics and cytotoxicity was probed to establish a connection between chemical structure and antiproliferation efficiency. With optimal assembly manner and delivery efficacy, the longest axial branched Pt(IV) prodrug CSS18 exhibited the most impressive therapeutic outcome, providing a potential path to more efficient nanocarriers for chemotherapeutic agents by chemical modulation and, giving insights into the rational design of reduction responsive platinum delivery system.
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