Cu配合物催化硼氢化钠还原CO2制备甲醇  

Cu complexes-catalyzed reduction of carbon dioxide to methanol with NaBH4

作　　者：王万辉 刘平[1,2] 邱立春[1,2] 王加升[1,2] 包明 Wan-Hui Wang;Ping Liu;Li-Chun Qiu;Jiasheng Wang;Ming Bao(State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian 116023,China;School of Chemical Engineering,Dalian University of Technology,Panjin 124221,China)

机构地区：[1]大连理工大学精细化工国家重点实验室,大连116023 [2]大连理工大学化工学院,盘锦124221

出　　处：《科学通报》2020年第31期3438-3445,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(21872015);辽宁省“兴辽英才计划”(XLYC1802030)资助。

摘　　要：利用廉价金属铜盐和N,N,N′,N′-四甲基乙二胺(TMED)、N,N′-二甲基乙二胺、乙二胺、联嘧啶等配体原位生成金属配合物,并用于催化硼氢化钠还原二氧化碳制备甲醇反应.分别考察了金属、配体、溶剂和阴离子对催化反应的影响,结果表明在常温常压条件下,催化剂CuI/TMED、CuI/N,N′-二甲基乙二胺、CuI/乙二胺、CuI/联嘧啶能高效催化硼氢化钠还原二氧化碳反应生成甲醇.在25℃和1 atm CO2条件下,CuI/TMED催化硼氢化钠还原二氧化碳反应生成甲醇的产率和TON最高分别达到47%和315.通过原位红外和核磁对催化反应进行研究,并提出可能的催化机理.Carbon dioxide is one of the most important greenhouse gases and leads to serious global warming.Therefore,transformation of CO2 to fuels such as methanol to establish methanol economy and mitigate CO2 emission has attracted much more attention.Homogeneous hydrogenation of CO2 to methanol is suffering from low catalytic activity and hash reaction conditions.Although hydroboration of CO2 to methanol can proceed under mild conditions,most of the hydrogen sources,such as BH3,HBCat,9-BBN,and HBpin,are expensive,sensitive to air,and difficult to operate.Development of efficient catalytic system with cheap catalyst and hydrogen source under mild conditions is highly desirable.In this study,we developed a novel catalytic system using cheap Cu salts and N,N-bidentate ligands such as N,N,N′,N′-tetramethylethylenediamine(TMED),N,N′-dimethyl-1,2-ethanediamine,ethylenediamine,and 2,2′-bipyrimidine,as in situ catalysts to catalyze hydroboration of carbon dioxide to methanol.The influences of metal salts,anions,ligands,and solvents on catalytic reaction were examined.The optimized conditions were determined as:0.02 mmol CuI,0.02 mmol TMED,6 mmol NaBH4,10 mLTHF,P(CO2)=1 atm,25℃.The results indicated that CuI/TMED,CuI/N,N′-dimethyl-1,2-ethanediamine,CuI/ethylenediamine,and CuI/2,2′-bipyrimidine could efficiently catalyze the reduction of carbon dioxide to methanol with sodium borohydride under ambient temperature and pressure.CuI/TMED(0.01 mmol)catalyst achieved a highest TON of 315 at 25℃under 1 atm CO2 for 12 h.A high yield of 47%for methanol was obtained after 24 h when CuI/TMED was used as catalyst under optimal conditions.These results suggest that the in situ Cu catalyst is highly efficient for CO2reduction to methanol with NaBH4.To understand the reaction mechanism,a systematic study with in-situ FTIR and 1H NMR were carried out.In-situ FTIRindicated generation of intermediates HCOOBX3,CH3OBX3(X=H,HCOO,Me O),and L-Cu-O2CH.1H NMR spectra of TMED,TMED+NaBH4,CuI/TMED+NaBH4 in d-THF suggested that CuI and TMED

关 键 词：二氧化碳还原 硼氢化钠 甲醇 Cu配合物 N N-双齿配体 

分 类 号：TQ223.121[化学工程—有机化工] TQ426