development of tri-lacunary polyoxometalates (POMs) of Na8H[A-PW9O34]·7H2O and Na8H[B-PW9O34]·19H2O (Na-A-PW9 and Na-B-PW9) as highly selective and efficient heterogeneous Lewis base catalysts for Knoevenagel condensation, cyanosilylation of various aldehydes and ketones and the synthesis of benzoxazole derivatives at 25 °C under mild conditions. Since both Na-A-PW9 and Na-B-PW9 display no characteristic porosity
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钠的多
金属氧酸盐-lacunary(多
金属氧酸盐)8 H [A-PW 9 ö 34 ]·7H 2 O和Na 8 H [B-PW 9 ö 34 ]·19H 2 O(
钠-A-PW 9和Na-B-PW 9)是高选择性和高效的均相Lewis碱催化剂,用于Knoevenagel缩合,各种醛和酮的
氰基
硅烷化以及在25°C下于温和条件下合成
苯并恶唑衍
生物。由于Na-A-PW 9和Na-B-PW 9由于没有显示出特征性的孔隙率,建议催化反应不仅在表面和界面上进行,而且在本体相中进行。催化剂可以容易地回收并重复使用至少六次而不会明显降低催化活性,并且催化剂的结构在循环后保持不变。Na-A-PW 9和Na-B-PW 9的多相催化剂易于制备,高效且可重复使用,具有进一步应用的巨大潜力。