Patel Anjali, Patel Jay
Polyoxometalates and Catalysis Laboratory, Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda Vadodara-390002 India
RSC Adv. 2020 Jun 9;10(37):22146-22155. doi: 10.1039/d0ra04119j. eCollection 2020 Jun 8.
A Ni salt of phosphomolybdic acid (NiHPMA) was synthesized and characterized by various physico-chemical techniques such as EDX, UV-Visible spectroscopy, FT-IR, Raman spectroscopy and XPS. FT-IR and Raman spectroscopy confirm the presence of Ni as a counter cation while UV-Visible and XPS studies to confirm the presence of Ni(ii) in the catalyst. The catalyst was evaluated for its bi-functional activity towards the tandem conversion of benzaldehyde to ethyl benzoate and it was found that very small amounts of Ni (2.64 × 10 mmol) enhance the selectivity towards benzoate. A detailed mechanistic study was carried out by UV-Visible and Raman spectroscopy to confirm that both intermediate species, Mo-peroxo and Ni-oxo, are responsible for higher selectivity towards esters. Further, a study to determine the effect of addenda atoms (heteropoly acid) was also carried out. The catalyst was also found to be viable for a number of aldehydes under optimized conditions.
合成了磷钼酸镍盐（NiHPMA），并通过多种物理化学技术对其进行了表征，如能谱分析（EDX）、紫外可见光谱、傅里叶变换红外光谱（FT-IR）、拉曼光谱和X射线光电子能谱（XPS）。傅里叶变换红外光谱和拉曼光谱证实了镍作为抗衡阳离子的存在，而紫外可见光谱和X射线光电子能谱研究则证实了催化剂中Ni(ii)的存在。对该催化剂将苯甲醛串联转化为苯甲酸乙酯的双功能活性进行了评估，发现极少量的镍（2.64×10 mmol）提高了对苯甲酸酯的选择性。通过紫外可见光谱和拉曼光谱进行了详细的机理研究，以证实中间物种钼过氧和镍氧均对酯的高选择性负责。此外，还进行了一项确定附加原子（杂多酸）影响的研究。在优化条件下，该催化剂对多种醛也具有可行性。
