高速发展的氟化工是化学工业的一个重要分支，制冷剂是氟化工的重要分支。氧化铬催化剂作为气相氟-氯交换反应合成新一代不可替代的制冷剂（ODS替代品）催化剂，也是ODS替代品合成的核心技术。然而，对于氧化铬催化剂在预氟化过程中物种的转化及气相氟-氯交换反应的机理，目前尚没有统一的认识。考虑到氧化铬催化剂往往由无定形CrO3、Cr2O3和晶相Cr2O3同时存在的状况。本项目设计了晶相Cr2O3催化剂、无定形Cr2O3-晶相Cr2O3复合催化剂和无定形CrO3-晶相Cr2O3复合催化剂三类模型催化剂。通过定量分析催化剂中三种氧化铬物种含量，研究三种氧化铬物种在氟化预处理过程的转化。结合催化剂的氟-氯交换反应性能（活性、选择性、稳定性），指认铬物种在反应中的作用以及与催化剂失活之间的关系。通过本项目的实施，为研发高性能、高稳定的氟-氯交换反应催化剂提供理论依据，促进ODS合成催化剂技术的进步。

Fluorine chemistry is a branch of modern chemical industry, in which refrigerants production is an important part. Chromium oxides are the key catalysts for F/Cl exchange reaction in the synthesis of new generation refrigerants and thus the core technique in the production of ODS substitutes. However, some issues such as translation of Cr species during the pre-fluorination process and the mechanism of F-Cl exchange reaction still needs further investigation. As chromium oxides mainly consist of amorphous CrO3, amorphous Cr2O3 and crystalline Cr2O3, in this project, we plan to design crystalline Cr2O3, amorphous Cr2O3-crystalline Cr2O3, amorphous CrO3-crystalline Cr2O3 as three model catalysts. Translation of these different Cr species during pre-fluorination process could be investigated by qualitatively estimating the contents of these species. Combined with catalytic performance (activity, selectivity and stability) of F-Cl exchange reaction over these catalysts, contributions of these Cr species and their influence on the catalyst deactivation could be evaluated. These works are helpful in development of highly efficient catalyst systems for F-Cl exchange reaction and production of ODS substitutes.