背景:已经合成并开发了负载在MCM-41上的Ni(II)和VO(IV)金属配合物的高效高级催化剂,用于将硫化物化学选择性氧化为亚砜,并将硫醇氧化偶联为其相应的二硫化物使用H2O2作为绿色有效的程序。所有亚砜和二硫化物均在短反应时间内以优异的产率获得。未观察到硫化物或硫醇的过度氧化,并且所有产物均以高纯度合成。这些催化剂可以回收并重复使用几次,而其催化活性没有任何明显损失。与文献中的旧催化剂相比,这些催化剂对亚砜和二硫化物衍生物的合成显示出更好的活性和选择性,这显示了这项工作的新颖性。
方法:首先,合成了介孔MCM-41,进一步,其表面被(3-氯丙基)-三乙氧基硅烷(CPTES)改性。然后,修饰的MCM-41(nPrCl-MCM-41)被腺嘌呤官能化。下一步,官能化的MCM-41(6AP-MCM-41)用作载体,用于固定镍和氧代钒作为最终催化剂(Ni-6AP-MCM-41或VO-6AP-MCM-41)。通过XRD对这些催化剂的结构和性能进行了鉴定,SEM,TGA,FT-IR,和AAS光谱分析。这些催化剂用于硫化物的化学选择性氧化和硫醇的氧化偶联。
结果:这些配合物在室温下很好地催化了所有反应。根据获得的结果,一些衍生物的羟基,包括2-(甲硫基)乙醇或2,2-(苯硫基)乙醇,在反应过程中保持不变。
结论:已发现该方法具有成本低的优点,效率高,高产量,recovery,和可重复使用的几个运行没有显著损失的催化活性。
BACKGROUND: A highly efficient superior catalyst of Ni (II) and VO (IV) metal complexes supported on MCM-41 has been synthesized and developed for chemoselective oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using H2O2 as a green and efficient procedure. All sulfoxides and disulfides were obtained in short reaction times with excellent yields. The over-oxidation of sulfides or thiols was not observed and all products were synthesized in high purity. These catalysts could be recovered and reused several times without any significant loss in their catalytic activity. Compared to the old catalysts in the literature, these catalysts showed better activity and selectivity for the synthesis of sulfoxide and disulfide derivatives, which shows the novelty of this work.
METHODS: At first, the
mesoporous MCM-41 was synthesized, and further, its surface was modified by (3-chloropropyl)-triethoxysilane (CPTES). Then, the modified MCM-41 (nPrCl-MCM- 41) was functionalized by adenine. In the next step, the functionalized MCM-41 (6AP-MCM- 41) was used as support for the immobilization of nickel and oxo-vanadium as final catalysts (Ni-6AP-MCM-41 or VO-6AP-MCM-41). The structure and properties of these catalysts have been identified by XRD, SEM, TGA, FT-IR, and AAS spectral analyses. These catalysts were used in the chemoselective oxidation of sulfides and oxidative coupling of thiols.
RESULTS: These complexes catalyzed all reactions well at room temperature. According to the results obtained, the hydroxyl groups of some derivatives, including 2-(methylthio) ethanol or 2,2-(phenylthio) ethanol, remained unchanged during the reaction.
CONCLUSIONS: The method has been found to possess the advantages of low cost, high efficiency, high yields, recovery, and reusability for several runs without significant loss in the catalytic activity.