Design of brand-new "Intercalation Catalysts" with specific lift-up function of Interlayer space

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05558
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34030:Green sustainable chemistry and environmental chemistry-related
• Research Institution: Chiba University
• Principal Investigator: Hara Takayoshi 千葉大学, 大学院工学研究院, 准教授 (60437358)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: アニオン交換 / 層状無機水酸化物 / 層空間拡張 / 固体塩基触媒 / 水溶媒 / クネベナーゲル縮合反応

Outline of Final Research Achievements

Acetate-intercalated layered yttrium hydroxides C2/Y-LRH was synthesized by a simple anion exchange method using Cl-/Y-LRH as a parent material. The anion exchange from chloride into acetate (C2) proceeded rapidly, as confirmed by the time resolved synchrotron-radiation X-ray diffraction (t-SXRD) analysis. In water solvent, the basal spacing of the C2/Y-LRH catalyst based on the (00l) plane increased from 1.00 nm under dry conditions to 1.35 nm, and this lifted up
layered structure was generated immediately (within 5 seconds). By use of the C2/Y-LRH catalyst, a wide range of substrates were converted into the corresponding α,β-unsaturated nitriles in water via Knoevenagel condensation. Our synthesized heterogeneous catalyst acted as a Bronsted base for this organic transformation, and it was reusable without any loss of its catalytic activity and selectivity.

Free Research Field

触媒化学

Academic Significance and Societal Importance of the Research Achievements

層状イットリウム水酸化物の層間内に酢酸イオンを導入したときに，水中で特異的に層間隔が拡張する「リフトアップ現象」を見出した．SPring-8内の粉末結晶構造解析ビームラインBL02B2でサブ秒オーダーでの放射光X線回折実験にて拡張過程を追跡したところ、水による層空間のリフトアップは数秒以内で完了していた．酢酸イオンと多量に存在する水分子とが層間内で複合体を形成することで基本層を持ち上げ，反応空間を拡張していると考えられる．この結果から，層状無機水酸化物の層空間を反応場として自由自在にデザインし，目的とする化学反応に適した反応空間を仕立て上げるように設計する方法論が確立できる可能性がある．