Thermodynamic equilibrium analysis of ring opening of decalin

► Endocyclic cracking is less favored due to entropy effects. ► Gibbs free energy of formation data calculated by quantum chemical method G3MP2. ► Ring opening of decalin is hindered by cracking and dehydrogenation reactions. ► Temperature <500 K and H2/HC ratio >4 maximize ring opening yields of decalin.