Calixarene-Capped Platinum Nanofluid for Pseudohomogeneous Catalytic Cracking and Heat Sink Enhancement of Ethylcyclohexane

To solve the heat management problem of supersonic aircraft, endothermic hydrocarbon fuels (EHFs) have been developed as both a coolant and a propellant. The pseudohomogeneous catalyst is an efficient way to improve the heat sink of EHFs. In this work, hydrocarbon soluble macrocyclic calixarene compound C-undecyl calix[4]2-(propylsulfanylmethyl)-resonrcinarene (C11–SC3) was synthesized and used as a stabilizer for hydrocarbon-dispersed Pt nanoparticles (Pt@C11–SC3). The morphological characterization results indicate that Pt nanoparticles are encapsulated by the calixarene, which helps the fabrication of ultrasmall Pt@C11–SC3. Ethylcyclohexane (ECH) was selected as a model substrate of EHFs to construct the Pt@C11–SC3/ECH nanofluid system for pseudohomogeneous catalytic cracking. The cracking test of the Pt@C11–SC3/ECH nanofluid was carried out in a batch reactor and a flow reactor under constant volume and pressure conditions. The distribution of cracking products displayed a significant improvement in terms of cracking conversion and a preferred heat absorbed reaction pathway, leading to a higher heat sink. There was a 16% maximum increase in heat sink in the constant pressure cracking tests with the addition of 0.01 wt % Pt@C11–SC3 at 700 °C. It provides a helpful method for heat sink enhancement of EHFs.