In this paper, the environmentally friendly synthesis of N-carboxy alanine anhydride (Ala-NCA) from alanine and dimethyl carbonate (DMC) over NaZnPO 4 was carried out in one-pot, and the NaZnPO 4 catalyst with the acid-base double active sites was prepared by the solid phase synthesis method. The X-ray diffraction spectrometer (XRD) was used to characterize the structure of NaZnPO 4 , and the reaction products were analyzed by the high performance liquid chromatography (HPLC) with evaporative

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... ght scattering detector (ELSD). The GC-MS characterized result of obtained Ala-NCA was extremely consistent with that of the standard sample, which indicated that Ala-NCA was synthesized successfully. When the reaction was carried out at 150 ℃ for 8 h, the maximum 46.84% yield of Ala-NCA can be obtained in DMF solvent. As the reaction temperature increased to 160 ℃, Ala-NCA yield significantly declined because of the instability of Ala-NCA at higher temperature. However, there was no Ala-NCA formation without catalyst existence because DMC is not easy to undergo carboxymethylation with amino acids. NaZnPO 4 could be recycled, but Ala-NCA yield declined to 38.62% after the fifth cycle. The reasons for that were attributed to the catalyst surface area reduction and the active site loss of Na-O and Zn 2+ . The reaction between DMC and amino acids over NaZnPO 4 were characterized by TG-MS-IR, and the possible catalytic mechanism was provided. Namely, Zn 2+ and Na-O in NaZnPO 4 perform an effective acid-base synergistic catalysis, on the one hand the basic Na-O active sites play an key role on amino group deprotonation, which promotes the carboxymethylation of amino acids with DMC, on the other hand the acid active sites of Zn 2+ can well catalyze the cyclization of intermediate into Ala-NCA. In this cyclization process, NaZnPO 4 also can transfer the trapped protons to carboxymethylation intermediate to facile the formation of target compounds.