Optimizing gas chromatography parameters for thermally unstable dicyclopentadiene mixtures analysis

Dicyclopentadiene (DCPD) is a versatile compound used in various applications, including resins, polymers, and high-energy-density (HED) fuels, such as exo-tetrahydrodicyclopentadiene (exo-THDCPD). DCPD reaction mixtures are typically analyzed using gas chromatography (GC), but this process can be challenging due to its thermal instability. At temperatures above 150 °C, it can undergo a reverse Diels-Alder reaction (RDAR), decomposing into cyclopentadiene (CPD). This decomposition can lead to significant errors in quantitative measurements, including conversion and yield. To address this issue, we conducted GC analyses at temperatures exceeding the RDAR threshold to investigate DCPD dissociation under various conditions, including GC inlet temperatures, gas flow rates, and solvents. Our study reveals that at inlet temperatures above 200 °C, accurately determining DCPD conversion is extremely difficult. Additionally, we report that the flow rate of the carrier gas has a negligible impact on the DCPD dissociation, while the choice of solvent significantly affects the detection of the CPD formed. Among the three solvents examined, dichloromethane (DCM) was found to be the most effective for detecting dissociated CPD.