Syntheses of new peroxo-polyoxometalates intercalated layered double hydroxides for propene epoxidation by molecular oxygen in methanol
Syntheses of new peroxo-polyoxometalates intercalated layered double hydroxides for propene epoxidation by molecular oxygen in methanol
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DOI：
10.1016/j.jcat.2007.03.025
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发表时间：
2007-06-10
影响因子：
7.3
通讯作者：
Sakanishi, Kinya
中科院分区：
文献类型：
--
作者：
Liu, Yanyong;Murata, Kazuhisa;Sakanishi, Kinya
以PdMAl-[PW_（11）O_（39）]（M = Mg ~（2+）或Zn ~（2+））为原料，用30%H_2O_2处理，合成了一种新型的过氧杂多酸插层水滑石。XRD、FT-IR和P-31 MAS NMR表明，层间阴离子[PW 11 O 39]（7-）主要转化为{PO 4 [WO（O-2）（2）]（4）}（3-）和[W2 O3（O-2）（4）（H2O）（2）]（2-）。Al-27 MAS NMR显示水镁石样层在合成过程中没有塌陷。PdMgAl-[PW 4 + W-2]催化剂在353 K下，以甲醇为溶剂，O-2为氧化剂，反应10 h，丙烯转化率为47.5%，环氧丙烷的选择性为91.5%。PdMgAl-[PW 4 + W-2]催化剂的催化性能主要归因于：类水镁石层中高活性的Pd粒子原位生成H2 O2，层间过氧聚氧乙烯酸盐在稀H2 O2条件下的强环氧化能力，以及碱性MgAl类水镁石层对烯烃环氧化的促进作用。PdMgAl-[PW 4 + W-2]可通过过滤分离并重复使用，而不会将活性组分浸出到溶剂中。(c)2007年爱思唯尔公司All rights reserved.
A new type of layered double hydroxides intercalated by peroxo-polyoxometalates was synthesized by treating PdMAl-[PW11O39] (M = Mg2+ or Zn2+) with 30% H2O2. XRD, FT-IR, and P-31 MAS NMR revealed that the interlayer anion [PW11O39](7-) was converted mainly to {PO4[WO(O-2)(2)](4)}(3-) and [W2O3(O-2)(4)(H2O)(2)](2-). Al-27 MAS NMR revealed that the brucite-like layers did not collapse during synthesis. PdMgAl-[PW4 + W-2] showed 91.5% selectivity for propene oxide at 47.5% conversion during propene epoxidation by O-2 in methanol at 353 K for 10 h. The catalytic ability of PdMgAl-[PW4 + W-2] can be attributed to the presence of highly active Pd particles in the brucite-like layers that generate H2O2 in situ, the strong epoxidation ability of interlayer peroxo-polyoxometalates with dilute H2O2, and the promotion effect of the basic MgAl-type brucite-like layers toward alkene epoxidation. Moreover, PdMgAl-[PW4 + W-2] can be separated and reused by filtration without leaching active components into the solvent. (c) 2007 Elsevier Inc. All rights reserved.