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Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds

[Image: see text] 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 d(0)-transition-metal cations such a...

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Autores principales: Aihara, Takeshi, Aoki, Wataru, Kiyohara, Shin, Kumagai, Yu, Kamata, Keigo, Hara, Michikazu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2023
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10103063/
https://www.ncbi.nlm.nih.gov/pubmed/37010448
http://dx.doi.org/10.1021/acsami.3c01629
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author Aihara, Takeshi
Aoki, Wataru
Kiyohara, Shin
Kumagai, Yu
Kamata, Keigo
Hara, Michikazu
author_facet Aihara, Takeshi
Aoki, Wataru
Kiyohara, Shin
Kumagai, Yu
Kamata, Keigo
Hara, Michikazu
author_sort Aihara, Takeshi
collection PubMed
description [Image: see text] 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 d(0)-transition-metal cations such as Ti(4+), Zr(4+), and Nb(5+) as B-site elements were successfully synthesized by a sol–gel method using dicarboxylic acids. Moreover, the specific surface area of SrTiO(3) was increased to 46 m(2) g(–1) by a simple procedure of changing the atmosphere from N(2) to air during calcination of an amorphous precursor. The resultant SrTiO(3) 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 analytically 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 infrared spectroscopy, and temperature-programmed desorption measurements using probe molecules such as pyridine, acetophenone, CO(2), and CHCl(3), 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 SrTiO(3) most likely enable SrTiO(3) to act as a bifunctional acid–base solid catalyst through cooperative activation of carbonyl compounds and TMSCN. This bifunctional catalysis through SrTiO(3) resulted in high catalytic performance even without a heat pretreatment, in sharp contrast to the performance of basic MgO and acidic TiO(2) catalysts.
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spelling pubmed-101030632023-04-15 Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds Aihara, Takeshi Aoki, Wataru Kiyohara, Shin Kumagai, Yu Kamata, Keigo Hara, Michikazu ACS Appl Mater Interfaces [Image: see text] 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 d(0)-transition-metal cations such as Ti(4+), Zr(4+), and Nb(5+) as B-site elements were successfully synthesized by a sol–gel method using dicarboxylic acids. Moreover, the specific surface area of SrTiO(3) was increased to 46 m(2) g(–1) by a simple procedure of changing the atmosphere from N(2) to air during calcination of an amorphous precursor. The resultant SrTiO(3) 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 analytically 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 infrared spectroscopy, and temperature-programmed desorption measurements using probe molecules such as pyridine, acetophenone, CO(2), and CHCl(3), 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 SrTiO(3) most likely enable SrTiO(3) to act as a bifunctional acid–base solid catalyst through cooperative activation of carbonyl compounds and TMSCN. This bifunctional catalysis through SrTiO(3) resulted in high catalytic performance even without a heat pretreatment, in sharp contrast to the performance of basic MgO and acidic TiO(2) catalysts. American Chemical Society 2023-04-03 /pmc/articles/PMC10103063/ /pubmed/37010448 http://dx.doi.org/10.1021/acsami.3c01629 Text en © 2023 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Aihara, Takeshi
Aoki, Wataru
Kiyohara, Shin
Kumagai, Yu
Kamata, Keigo
Hara, Michikazu
Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds
title Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds
title_full Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds
title_fullStr Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds
title_full_unstemmed Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds
title_short Nanosized Ti-Based Perovskite Oxides as Acid–Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds
title_sort nanosized ti-based perovskite oxides as acid–base bifunctional catalysts for cyanosilylation of carbonyl compounds
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10103063/
https://www.ncbi.nlm.nih.gov/pubmed/37010448
http://dx.doi.org/10.1021/acsami.3c01629
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