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Title
Japanese:Nanosized Ti-Based Perovskite Oxides as Acid-Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds 
English:Nanosized Ti-Based Perovskite Oxides as Acid-Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds 
Author
Japanese: Takeshi Aihara, Wataru Aoki, Shin Kiyohara, Yu Kumagai, Keigo Kamata, Michikazu Hara.  
English: Takeshi Aihara, Wataru Aoki, Shin Kiyohara, Yu Kumagai, Keigo Kamata, Michikazu Hara.  
Language English 
Journal/Book name
Japanese:ACS Applied Materials & Interfaces 
English:ACS Applied Materials & Interfaces 
Volume, Number, Page Vol. 15    No. 14    pp. 17957-17968
Published date Apr. 2023 
Publisher
Japanese:American Chemical Society 
English:American Chemical Society 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL https://doi.org/10.1021/acsami.3c01629
 
DOI https://doi.org/10.1021/acsami.3c01629
Abstract The development of effective solid acid-base bifunctional catalysts remains a challenge because of the difficulty associated with designing and controlling their active sites. In the present study, highly pure perovskite oxide nanoparticles with d0-transition-metal cations such as Ti4+, Zr4+, and Nb5+ as B-site elements were successfully synthesized by a sol-gel method using dicarboxylic acids. Moreover, the sp. surface area of SrTiO3 was increased to 46 m2 g-1 by a simple procedure of changing the atm. from N2 to air during calcination of an amorphous precursor. The resultant SrTiO3 nanoparticles showed the highest catalytic activity for the cyanosilylation of acetophenone with trimethylsilyl cyanide (TMSCN) among the tested catalysts not subjected to a thermal pretreatment. Various aromatic and aliphatic carbonyl compounds were efficiently converted to the corresponding cyanohydrin silyl ethers in good-to-excellent yields. The present system was applicable to a larger-scale reaction of acetophenone with TMSCN (10 mmol scale), in which 2.06 g of the anal. pure corresponding product was isolated. In this case, the reaction rate was 8.4 mmol g-1 min-1, which is the highest rate among those reported for heterogeneous catalyst systems that do not involve a pretreatment. Mechanistic studies, including studies of the catalyst effect, Fourier transform IR spectroscopy, and temperature-programmed desorption measurements using probe mols. such as pyridine, acetophenone, CO2, and CHCl3, and the poisoning effect of pyridine and acetic acid toward the cyanosilylation, revealed that moderate-strength acid and base sites present in moderate amounts on SrTiO3 most likely enable SrTiO3 to act as a bifunctional acid-base solid catalyst through cooperative activation of carbonyl compounds and TMSCN. This bifunctional catalysis through SrTiO3 resulted in high catalytic performance even without a heat pretreatment, in sharp contrast to the performance of basic MgO and acidic TiO2 catalysts.

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