Nile Red as a Fluorescence Marker and Antioxidant for Regenerative Fuels

This article contributes to the ongoing dialogue regarding the future application of renewable e‐fuels as part of a holistic solution to the energy crisis. In order to be able to continue using internal combustion engines in a sustainable manner, it must be ensured that these engines are operated exclusively with renewable, CO<jats:sub>2</jats:sub>‐neutral fuels. One way to achieve this is the use of a fluorescence sensor in the vehicle in combination with fuels that are labeled with a fluorescence marker. This study presents an investigation into the use of the benzophenoxazine dye Nile red as a fluorescent marker for distinguishing fossil from renewable fuels. In addition to assessing the stability of the fluorescent marker against thermo‐oxidative aging, the study probes its antioxidative impact on fuel aging, by comparing unlabeled and with Nile red labeled aged fuels. Furthermore, an examination of fuel‐specific parameters underscores the positive effect of Nile red on fuel stability. A comparison with the antioxidant butylated hydroxytoluene confirms the antioxidant effect of Nile red.