Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction
作者:Xiaohang Liang、Xinxin Peng、Dan Liu、Changjiu Xia、Yibin Luo、Xingtian Shu
DOI:10.1016/j.mcat.2021.111750
日期:2021.7
dissociated from the ammonium salt would chelate with the linear Ti-η1(OOH) species and form a bridged Ti-η2(OOH)-R species, which is more stable, more weaker in epoxide adsorption and acidity as well. Therefore, side reactions and H2O2 decomposition would be suppressed, and both alkene conversion and epoxide selectivity would be promoted simultaneously. On the other hand, the excessive NH3•H2O (NH3/Ti>1) or
摘要 详细研究了铵盐对Ti-BEA沸石环氧化性能的影响。设计了有或没有铵盐的烯烃环氧化、环氧化物副反应和H2O2分解的实验,并采用紫外-可见光谱分析了钛氢过氧化物的结构。结果表明,从铵盐中解离出来的氨(或胺)会与线性 Ti-η1(OOH) 物种螯合,形成桥接 Ti-η2(OOH)-R 物种,在环氧化物中更稳定,更弱吸附和酸度也一样。因此,副反应和 H2O2 分解会被抑制,同时烯烃转化率和环氧化物选择性都会得到提高。另一方面,过量的 NH3•H2O (NH3/Ti> 1) 或 NaOH 与 Ti-η2(OOH)-R 物种键合,生成盐状 Ti-η2(OO)-M+ 物种,导致 Ti 活性中心失活。而对于铵盐,例如 NH4Cl,有限的解离度以及酸性环境有助于 Ti 活性中心保持高活性。总之,这项工作为 Ti-BEA 沸石提供了一种实用的 Ti 活性中心调谐方法,以及对其 Ti-hydroperoxo
Temperature-Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins
immobilization of tungsten peroxo complex was highly temperature-dependent. The tungsten peroxo complex can dissociate and diffuse into the liquid phase at reaction temperature, resulting in a homogeneous reaction. Nevertheless, the catalytically active species was anchored on the imidazole-functionalized silica by hydrogen bonding as the temperature was lowered to 0 °C after the reaction, which thus offered a
合成了由二齿吡啶甲酸配体稳定的过氧钨配合物,然后成功地将其固定在咪唑官能化的二氧化硅上。固定化的钨基催化剂被用作由烯烃和甲醇与H2 O2一锅合成β-烷氧基醇的有效催化剂。关于催化剂评估和通过各种方法表征的结果,证明了过氧化钨配合物的固定化高度依赖于温度。过氧化钨络合物可以在反应温度下解离并扩散到液相中,从而导致均相反应。然而,随着反应后温度降低至0°C,催化活性物质通过氢键键合固定在咪唑官能化的二氧化硅上,因此,它提供了一种高效的方法来使催化剂连续循环使用。另外,在相对温和的条件下,H 2 O 2可将各种烯烃以良好的转化率和选择性转化为相应的β-烷氧基醇。
HYDROCRACKING CATALYST, METHOD FOR PRODUCING SAME, AND METHOD FOR PRODUCING HYDROXY COMPOUND USING SAID CATALYST
申请人:Yoshii Kiyotaka
公开号:US20140288335A1
公开(公告)日:2014-09-25
The present invention provides a hydrocracking catalyst obtainable by mixing a metal compound (A) including any one metal of Groups 3 to 11 of the Periodic Table, a compound (B) including at least one compound selected from the group consisting of a ruthenium oxide compound (B1) and a high-valence compound (B2) including any metal of Groups 8 to 11 of the Periodic Table, and a metal oxide (C) including a metal of Group 5, Group 6 or Group 7 of the Periodic Table, and conducting reduction treatment.
Novel polymer-supported ruthenium and iron complexes that catalyze the conversion of epoxides into diols or diol mono-ethers: clean and recyclable catalysts
作者:Sun Hwa Lee、Eun Yong Lee、Dong-Woo Yoo、Sung Jin Hong、Jung Hwan Lee、Han Kwak、Young Min Lee、Jinheung Kim、Cheal Kim、Jin-Kyu Lee
DOI:10.1039/b707028d
日期:——
Polymer-supported metal (Fe or Ru) complexes for epoxide ring opening reactions were successfully prepared by anchoring the bis(2-picolyl)amine ligand onto the polymer poly(chloromethylstyrene-co-divinylbenzene) (PCD); the catalysts showed heterogeneous catalytic activity and easy recyclability in the ring opening reactions of various epoxide substrates with methanol or H2O at room temperature under mild and neutral conditions.
solid acid catalyst was prepared by tandem post‐functionalization of MIL‐101(Cr) and utilized for acetic acid esterification and alcoholysis of epoxides under solvent‐free conditions. First, MIL‐101(Cr) was functionalized with pyrazine to achieve MIL‐101(Cr)‐Pyz. Afterwards, the nucleophilic reaction of MIL‐101(Cr)‐Pyz with 1,3‐propane sultone and next acidification with diluted sulfuricacid gave