Bukharbayeva Farida, Zharmagambetova Alima, Talgatov Eldar, Auyezkhanova Assemgul, Akhmetova Sandugash, Jumekeyeva Aigul, Naizabayev Akzhol, Kenzheyeva Alima, Danilov Denis
Laboratory of Organic Catalysis, D.V. Sokolsky Institute of Fuel, Catalysis, and Electrochemistry, Kunaev Str. 142, Almaty 050010, Kazakhstan.
Interdisciplinary Resource Center for Nanotechnology, St. Petersburg State University, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia.
Molecules. 2024 Sep 26;29(19):4584. doi: 10.3390/molecules29194584.
The proposed paper describes a simple and environmentally friendly method for the synthesis of three-component polymer-inorganic composites, which includes the modification of zinc oxide or montmorillonite (MMT) with chitosan (CS), followed by the immobilization of palladium on the resulting two-component composites. The structures and properties of the obtained composites were characterized by physicochemical methods (IRS, TEM, XPS, SEM, EDX, XRD, BET). Pd-CS species covered the surface of inorganic materials through two different mechanisms. The interaction of chitosan polyelectrolyte with zinc oxide led to the deprotonation of its amino groups and deposition on the surface of ZnO. The immobilization of Pd on CS/ZnO occurred by the hydrolysis of [PdCl], followed by forming PdO particles by interacting with amino groups of chitosan. In the case of CS/MMT, protonated amino groups of CS interacted with negative sites of MMT, forming a positively charged CS/MMT composite. Furthermore, [PdCl] interacted with the -NH sites of CS/MMT through electrostatic force. According to TEM studies of 1%Pd-CS/ZnO, the presence of Pd nanoclusters composed of smaller Pd nanoparticles of 3-4 nm in size were observed on different sites of CS/ZnO. For 1%Pd-CS/MMT, Pd nanoparticles with sizes of 2 nm were evenly distributed on the support surface. The prepared three-component CS-inorganic composites were tested through the hydrogenation of 2-propen-1-ol and acetylene compounds (phenylacetylene, 2-hexyn-1-ol) under mild conditions (T-40 °C, P-1 atm). It was shown that the efficiency of 1%Pd-CS/MMT is higher than that of 1%Pd-CS/ZnO, which can be explained by the formation of smaller Pd particles that are evenly distributed on the support surface. The mechanism of 2-hexyn-1-ol hydrogenation over an optimal 1%Pd-CS/MMT catalyst was proposed.
所提出的论文描述了一种简单且环保的合成三组分聚合物 - 无机复合材料的方法，该方法包括用壳聚糖（CS）对氧化锌或蒙脱石（MMT）进行改性，然后将钯固定在所得的双组分复合材料上。通过物理化学方法（红外光谱、透射电子显微镜、X射线光电子能谱、扫描电子显微镜、能谱分析、X射线衍射、比表面积分析）对所得复合材料的结构和性能进行了表征。钯 - 壳聚糖物种通过两种不同机制覆盖无机材料表面。壳聚糖聚电解质与氧化锌的相互作用导致其氨基去质子化并沉积在氧化锌表面。钯在壳聚糖/氧化锌上的固定是通过[PdCl]的水解，然后与壳聚糖的氨基相互作用形成PdO颗粒来实现的。在壳聚糖/蒙脱石的情况下，壳聚糖的质子化氨基与蒙脱石的负位点相互作用，形成带正电的壳聚糖/蒙脱石复合材料。此外，[PdCl]通过静电力与壳聚糖/蒙脱石的 -NH位点相互作用。根据对1%钯 - 壳聚糖/氧化锌的透射电子显微镜研究，在壳聚糖/氧化锌的不同位点观察到由尺寸为3 - 4纳米的较小钯纳米颗粒组成的钯纳米团簇的存在。对于1%钯 - 壳聚糖/蒙脱石，尺寸为2纳米的钯纳米颗粒均匀分布在载体表面。通过在温和条件（温度 - 40°C，压力 - 1个大气压）下对2 - 丙烯 - 1 - 醇和乙炔化合物（苯乙炔、2 - 己炔 - 1 - 醇）进行氢化反应，对制备的三组分壳聚糖 - 无机复合材料进行了测试。结果表明，1%钯 - 壳聚糖/蒙脱石的效率高于1%钯 - 壳聚糖/氧化锌，这可以通过在载体表面均匀分布的较小钯颗粒的形成来解释。提出了在最佳的1%钯 - 壳聚糖/蒙脱石催化剂上2 - 己炔 - 1 - 醇氢化反应的机理。
