Synthesis of 1,4-Butanediol via One-Step Esterification–Hydrogenation of Succinic Anhydride over Cu-ZnO Catalysts: A Mechanism Study of Reaction and Deactivation

Stable production of 1,4-butanediol (BDO) via one-step esterification–hydrogenation (OEH) of succinic anhydride (SA) was achieved over Cu-ZnO catalysts in a fixed-bed reactor. Based on the variation tendency in the stability tests and the results of XRD, ICP-OES, TEM, quasi-in situ XPS, and quasi-in situ XAS of the catalysts before and after the reaction, the reconstruction of Cu-ZnO induced by the intermediate monomethyl succinate (MMSA) was further confirmed, and the effective active site Cu + was responsible for the adsorption and activation of the ester group. Combining with the different stability results of SA to BDO, succinic acid to BDO, and dimethyl succinate (DMS) to BDO, a reaction pathway for OEH of SA/succinic acid to BDO proceeded via the intermediate MMSA instead of DMS. In situ IR spectra further revealed the reaction pathway of hydrogenation of DMS, MMSA, and succinic acid on Cu-ZnO, and the deactivation mechanism of Cu-ZnO in DMS hydrogenation─formation and adsorption of polyesters on Cu + . This study could provide some valuable clues for fabricating highly efficient and stable Cu-based catalysts for the one-step production of BDO from SA or succinic acid.