Researchers at the Dalian Institute of Chemical Physics in China report a two-step method for the synthesis of jet-fuel-range high-density polycycloalkanes from polycarbonate waste under mild conditions. An open-access paper on their work appears in the RSC journal Green Chemistry.

Plastics are a family of organic polymers which are widely used in our life. Since 1950s, about 6.3 billion tons of plastics have been produced worldwide. However, only a small part of plastic was recycled (9%) or incinerated (12%). Most of them were discarded after usage. Moreover, the chemical structure of most plastics renders them resistant to bio-degradation, which will lead to a lot of environmental and ecological problems.

… Polycycloalkanes are major components of advanced jet fuels which have been widely used for aircraft and propulsion. Compared with conventional jet fuels, polycycloalkanes have higher density (or volumetric heat value). Therefore, the utilization of polycycloalkanes can significantly increase the flight range, payload and speed of aircraft without change the volume of oil tank. To the best of our knowledge, there is no report about the production of high-density aviation fuel with waste plastics.

… In this work, it was first reported that jet fuel range polycycloalkanes can be selectively produced by the alcoholysis of PC waste, followed by hydrodeoxygenation. The polycycloalkanes as obtained have high density. As a potential application, they can be used as high-density aviation fuels or additives to increase the volumetric heat values of current jet fuels.

—Tang et al.

Strategy for the synthesis of jet fuel range C₁₃-C₁₅ polycycloalkanes with PC wastes. Tang et al.

In the first step of the process, polycarbonate (PC) waste is converted to bisphenol by methanolysis. In the second step, the bisphenol was further converted to polycycloalkanes by hydrodeoxygenation.

In the absence of a catalyst, a high yield (~90%) of bisphenol A was achieved from the methanolysis of PC waste after the reaction was carried out at 180 C for 3 hours.

Subsequently, the bisphenol A was hydrodeoxygenated to jet fuel range C₁₅ bicycloalkanes under the co-catalysis of activated carbon loaded noble metal and acidic zeolites.

Among the investigated catalyst systems, the combination of Pt/C and zeolite H-β (denotes as Pt/C + H-β) exhibited the best performance. The researchers attributed this to the high activity of Pt/C for hydrogenation of the benzene ring, and the high pore size and acidity of H-β zeolite. The Pt/C + H-β catalyst is also applicable for the synthesis of C₁₃-C₁₅ polycycloalkanes with bisphenols which can be derived from lignocellulose.

Resources

• Hao Tang, Yan-Cheng Hu, Guangyi Li, Ai-Qin Wang, Guoliang Xu, Cong Yu, Xiaodong Wang, Tao Zhang and Ning Li (2019) “Synthesis of jet fuel range high-density polycycloalkanes with polycarbonate waste” Green Chemistry doi: 10.1039/C9GC01627A