Acid-base concerted mechanism in the dehydration of 1,4-butanediol over bixbyite rare earth oxide catalysts

详细信息    查看全文

• 作者：Fumiya Sato^a ; ¹ ; Satoshi Sato^a ; ^{satoshi@faculty.chiba-u.jp" class="auth_mail} ; Yasuhiro Yamada^a ; Masashi Nakamura^a ; Akinobu Shiga^b
• 关键词：Density functional study ; Paired interaction orbital ; Rare earth oxide ; Dehydration ; 1 ; 4-Butanediol ; Acid&ndash ; base concerted mechanism
• 刊名：Catalysis Today
• 出版年：1 May, 2014
• 年：2014
• 卷：226
• 期：Complete
• 页码：124-133
• 全文大小：3744 K

文摘

Catalytic activity of rare earth oxides (REOs) in the vapor-phase dehydration of 1,4-butanediol to produce 3-buten-1-ol varies with lattice parameters of REOs. In order to clarify the adsorption structure and the reaction mechanism, adsorption energy of 1,4-butanediol on bixbyite REO, such as Sc₂O₃, Y₂O₃, Dy₂O₃, Ho₂O₃, and Er₂O₃, {2 2 2} surface was calculated with density functional theory (DFT), and paired interacting orbitals (PIO) calculation of the adsorption state between 1,4-butanediol and Er₂O₃ was executed. The DFT study elucidates that the catalytic activity is correlated with adsorption energy. The PIO study clarifies the interactions between the reactive atoms of 1,4-butanediol and Er₂O₃ surface: tridentate interactions between a position-2 hydrogen atom of diol and an oxygen anion on Er₂O₃ and between each OH group of diol and erbium cations on Er₂O₃, and an intramolecular repulsive interaction between the position-1 carbon atom and the oxygen atom of OH group are observed. These results suggest that the position-2 hydrogen atom is firstly abstracted by a basic oxygen anion and that the position-1 hydroxyl group is subsequently abstracted by an acidic erbium cation. Another OH group on position 4 plays an important role of anchoring the diol to the Er₂O₃ surface. Therefore, it is proved that the dehydration of 1,4-butanediol over REOs proceeds via acid-base concerted mechanism.