Keggin-type phosphomolibdic acid (H3PMo12O40, PMo12) encapsulated in the mesocages of chromium-based terephthalate metal–organic framework (MIL-101), was established to be an active and new green catalyst for the adipic acid (AA) synthesis via cyclohexanone (-One) oxidation in free solvent conditions and hydrogen peroxide as green oxidant. In this paper, we wish to report the synthesis of MIL-101 with different high loadings of the PMo12 nanocrystals incorporated within the large pores of MIL-101. Two and five POMs per large cavity can be incorporated into the matrix of MIL-101 respectively, xH3PMo12@ MIL101 with x=0, 2 and 5, they were characterized by several physic-chemical technics, then investigated in the reaction oxidation with 30 mmol –One at 90 ° C for 20h. A sequenced addition of 0.5ml of H2O2 (30%) was made every 30 min. The catalysts have shown good activity and the purity of AA was invistigeted by 1H and 13C NMR.