CC BY 4.0 UnportedMaas, JanMielke, Alexander2022-06-232022-06-232020https://oa.tib.eu/renate/handle/123456789/9135https://doi.org/10.34657/8173We consider various modeling levels for spatially homogeneous chemical reaction systems, namely the chemical master equation, the chemical Langevin dynamics, and the reaction-rate equation. Throughout we restrict our study to the case where the microscopic system satisfies the detailed-balance condition. The latter allows us to enrich the systems with a gradient structure, i.e. the evolution is given by a gradient-flow equation. We present the arising links between the associated gradient structures that are driven by the relative entropy of the detailed-balance steady state. The limit of large volumes is studied in the sense of evolutionary Γ-convergence of gradient flows. Moreover, we use the gradient structures to derive hybrid models for coupling different modeling levels.enghttps://creativecommons.org/licenses/by/4.0/530Chemical master equationDetailed balanceGradient flowHybrid modelsReaction-rate equationArticle