Catalytic cracking of 4-(1-naphthylmethyl)bibenzyl in sub- and supercritical water

- In the subcritical water, NMBB conversion was well beyond that in the supercritical water environment.
- In contrast to N2 atmosphere, H2 atmosphere showed better NMBB conversion.
- Products distribution was controllable by changing reaction conditions, thus different target products can be obtained.
- Subcritical water served as a cheap and environmental H donor in coal-derived liquids upgrading.

The upgrading and reforming of coal-derived liquids are necessary for the application of high value-added liquid fuels, but the processing is difficult due to the amounts of impurities. In this paper, the catalytic cracking of 4-(1-naphthylmethyl)bibenzyl (NMBB) as a model reaction was studied deeply under sub- and supercritical water environment. Water might serve as a cheap and environmental H donor, which was more efficient than the supplied H2 in the processing of coal-derived liquids upgrading. Meanwhile, sub- and supercritical water could provide a homogeneous reaction environment for NMBB cracking as special solvents. The NMBB conversion under subcritical water was much higher than that under supercritical water. Furthermore, for H2 atmosphere, NMBB conversion was higher than that of N2 atmosphere, indicating that the process of in-situ H2 formation from subcritical water was more easily. Therefore, the cracking of NMBB under subcritical water and H2 atmosphere could be regarded as a reasonable reaction condition.

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