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Linear scaling relations of free energies have proved to be one of powerful concepts in metal and oxide catalysis.Here we attempt to extend it to zeolite catalysis by taking olefins methylation in MTH(methanol-to-hydrocarbons)or MTO(methanol-to-olefins)conversion as an example.All periodic DFT calculations were performed using GPAW package.The BEEF-vdW functional was used to take van der Waals interaction into account.The acid strength of CHA/AlPO-34,AEI/AlPO-18,AFI/AlPO-5 were changed by isomorphic substitution in the framework.The ammonia adsorption enthalpy(ΔHads(NH3))was identified as a good reactivity descriptor for acid strength.Good scaling relations were observed for transition state energies in both concerted and stepwise routes as a function of ΔHads(NH3).The slope of the established linear scaling relations is almost unchanged for the methylation of different olefins(ethene,propene,and butene)in the same framework.However,the slope changes with the framework structures.By constructing a general formula,we established the scaling relations of transition state energies with acid strength and olefin length in different frameworks.By employing microkinetic model of propene methylation in CHA/AlPO-34,we proposed that Mg-AlPO-34 is the most active catalyst for olefin methylation,consistent with the experimental findings.This work opens an exciting new avenue for understanding and rationally designing zeolite catalysts guided by descriptors-based first principles calculations.