2024-03-28T09:27:11Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/808252022-11-17T02:08:08Zhdl_2115_20051hdl_2115_144Cs-Beta with an Al-rich composition as a highly active base catalyst for Knoevenagel condensationOtomo, RyoichiOsuga, RyotaKondo, Junko N.Kamiya, YuichiYokoi, ToshiyukiBetaIon exchangeKnoevenagel condensationOSDA-freeSolid base450Ion-exchange of an Al-rich zeolite beta, synthesized by organic structure-directing agent-free method (Beta-OF), was studied for application as a base catalyst. While the as-synthesized Beta-OF in Na-form itself had base sites and showed moderate catalytic activity for Knoevenagel condensation, the ion-exchange with Cs+ improved the catalytic activity. For Knoevenagel condensation of benzaldehyde with ethyl acetoacetate, the catalytic activity of Beta-OF ion-exchanged with Cs+ largely surpassed that of the conventional zeolite beta with less Al content. CO2-TPD and IR observation with chloroform as a probe molecule revealed that the Cs-exchanged Beta-OF had strong base sites comparable to Cs-exchanged Y zeolite. Base strength of Beta-OF was stronger than that expected by Sanderson's theory. A local high density of Al atoms in the framework of Beta-OF resulted in the unexpected base property and high catalytic activity.ElsevierJournal Articleapplication/pdfhttp://hdl.handle.net/2115/80825https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/80825/1/190206-Alkali-Text-OR.pdf0926-860XAA10821202Applied catalysis A-general57520242019-04-05enginfo:doi/10.1016/j.apcata.2019.02.014© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/author