Co^(2+)/Cu^(2+)掺杂型铋杂多酸的制备及催化烯烃的研究

Synthesis of Bismuth(Bi~Ⅲ)-Contained Polyoxometalates Doped with Co^(2+)/Cu^(2+) as Catalysts for the Oxidation of Olefins with O_2

以多功能无毒且环境友好的铋(Bi~Ⅲ)为杂原子制备了Na_(12)[Bi_2W_(22)O_(74)(OH_)2]·42H_2O(Bi-POM)、Na_(10)[Bi_2W_(20)Co_2O_(70)(H_2O)_6]·39H_2O(Bi-Co-POM)以及Na_8[Bi_2W_(20)Cu_2O_(68)(OH)_2(H_2O)_6]·25H_2O(Bi-Cu-POM)含铋杂多酸催化剂,并用于以分子氧为氧化剂催化环己烯转化为环己烯酮的羰基化反应。这些复合物通过FT-IR、UV、TG/DSC以及XRD等分析方法对其结构进行了表征。结果表明Bi-POM催化剂对环己烯烯丙位羰基化反应具有较高的催化活性,掺杂Co^(2+)或Cu^(2+)金属离子后催化活性进一步提升。Bi-Co-POM催化剂展示了最优的催化性能,在最佳反应条件下(O_2氛围,60℃,8 h),催化氧化环己烯(作为模板)转化率高达85.9%,2-环己烯-1-酮的选择性高达91.6%。并探究了Bi-Co-POM催化剂在最优条件下对不同反应底物的普遍适用性,提出了可能的催化氧化机理。

Functional, non-toxic and environmental friendly Bim-contained polyoxometalates （POM） catalysts including Na12[Bi2W22O74（OH）2]·42H2O（Bi-POM）, Na10[Bi2W20Co2O70（H2O）6]·39H2O（Bi-Co-POM） and Nas[Bi2W20C2O68（OH）2（HEO）6]·25H2O（Bi-Cu-POM） were prepared. They could serve as an efficient catalyst for the allylic oxidation of cyclohexene using molecular oxygen （O2） as the oxidant. These compounds were characterized by FT-IR, UV, TG/DSC, and XRD. All three Bim-contained polyoxometalates （POM） efficiently catalyzed cyclohexene into 2-cyclohexene-1-one, and the catalytic activity was greatly improved when Co2＋ or Cue＋ was doped into Bi-POM. The Bi-Co-POM catalyst showed a higher catalytic efficiency up to 85.9% for the conversion of cyclohexene （chosen as model substrate） and the selectivity of the corresponding carbonyl compound was 91.6% at 60℃ for 8 h. Different olefins were also applicable when the Bi-Co-POM catalyst was used under the optimized reaction conditions. Based on the results, a possible mechanism of the oxidation was proposed.