Since no reliable kinetic data for NH3 sorption using MgCl2 could be found in literature, the absorption rate constant is arbitrarily set to 𝑘 = 10 mol s Pa kg in order to make it fast compared to the synthesis kinetics. This assumption reflects observations from breakthrough experiments reported in literature, where the NH3 molar fraction is close to zero until the breakthrough occurs, indicating that NH3 sorption is at least as fast as synthesis . In dynamic equilibrium, 𝑟 = 𝑟 , and the desorption rate constant can thus be expressed as