Effect of cis/trans molecular structures on pyrolysis performance and heat sink of decalin isomers

Abstract

Decalin is considered as an important compound of high-energy-density endothermic fuel, which is an ideal on-board coolant for thermal management of advanced aircraft. However, decalin contains two isomers with a tunable composition, and their effects on the pyrolysis performance, such as the heat sink and coking tendency have not been demonstrated. Herein, we investigated the pyrolysis of decalin isomers, i.e., cis-decalin, trans-decalin and their mixtures (denoted as mix-decalin), in order to clarify the effects of the cis-/trans-structures on the pyrolysis performance of decalin fuels. The pyrolysis results confirmed that conversion of the tested fuels (600–725 °C, 4 MPa) decreased in the order cis-decalin > mix-decalin > trans-decalin. Detailed analyses of the pyrolysis products were used to compare the product distributions from cis-decalin, mix-decalin and trans-decalin, and the yields of some typical components (such as cyclohexene, 1-methylcyclohexene, benzene and toluene) showed significant differences, which could be ascribed to deeper cracking of cis-decalin. Additionally, the heat sinks and coking tendencies of the decalins decreased in the order cis-decalin > mix-decalin > trans-decalin. This work demonstrates the relationship between the cis/trans structures and the pyrolysis performance of decalin, which provides a better understanding of the structure-activity relationships of endothermic hydrocarbon fuels.

Key words： endothermic fuel; decalin; pyrolysis; heat sink; molecular structure

Competing interests

The authors declare that they have no competing interests.

Acknowledgements

The authors appreciate the financial support from the National Key R&D Program of China (Grant No. 2021YFC2103701), the Haihe Laboratory of Sustainable Chemical Transformations for financial support, the Postdoctoral Science Foundation of China (Grant No. 2021M702810) and the National Natural Science Foundation of China (Grant No. 22208295)

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11705-023-2375-z and is accessible for authorized users.

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