Jianxing Gan, Yoshinao Nakagawa, Mizuho Yabushita and Keiichi Tomishige
{"title":"Non-noble metal heterogeneous catalysts for hydrogen-driven deoxydehydration of vicinal diol compounds†","authors":"Jianxing Gan, Yoshinao Nakagawa, Mizuho Yabushita and Keiichi Tomishige","doi":"10.1039/D4GC02006E","DOIUrl":null,"url":null,"abstract":"<p >Noble-metal-free heterogeneous catalysts for deoxydehydration (DODH) using H<small><sub>2</sub></small> as a reductant were developed. Among various transition metals examined as additives to modify the MoO<small><sub><em>x</em></sub></small>/TiO<small><sub>2</sub></small> catalyst, Cu showed good conversion and selectivity in the transformation of 1,4-anhydroerythritol (1,4-AHERY) to 2,5-dihydrofuran (2,5-DHF). The performance of the MoO<small><sub><em>x</em></sub></small>–Cu/TiO<small><sub>2</sub></small> catalysts was comparable to those modified with either Ag or Au instead of Cu. Upon the combination of two Mo precursors, <em>i.e.</em> (NH<small><sub>4</sub></small>)<small><sub>6</sub></small>Mo<small><sub>7</sub></small>O<small><sub>24</sub></small> and Na<small><sub>2</sub></small>MoO<small><sub>4</sub></small>, the selectivity of the catalyst (MoO<small><sub><em>x</em></sub></small>–Cu–Na/TiO<small><sub>2</sub></small>) was further enhanced to achieve 81% yield of 2,5-DHF. This catalyst also exhibited broad substrate scope including cyclic and linear alkyl vicinal diols and tartaric ester. Furthermore, MoO<small><sub><em>x</em></sub></small>–Cu–Na/TiO<small><sub>2</sub></small> was reusable at least three times after its calcination as regeneration. The reaction was almost zero-order with respect to the H<small><sub>2</sub></small> pressure and 1,4-AHERY concentration, suggesting that the release of the alkene is the rate-determining step. The comprehensive characterization using STEM, XRD and XAFS provided insights into the surface structure of the catalyst, revealing that H<small><sub>2</sub></small> is activated over Cu particles and subsequently transferred to Mo cluster species on the TiO<small><sub>2</sub></small> surface <em>via</em> the spillover effect to proceed with the DODH reaction.</p>","PeriodicalId":78,"journal":{"name":"Green Chemistry","volume":null,"pages":null},"PeriodicalIF":9.3000,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Green Chemistry","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/gc/d4gc02006e","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Noble-metal-free heterogeneous catalysts for deoxydehydration (DODH) using H2 as a reductant were developed. Among various transition metals examined as additives to modify the MoOx/TiO2 catalyst, Cu showed good conversion and selectivity in the transformation of 1,4-anhydroerythritol (1,4-AHERY) to 2,5-dihydrofuran (2,5-DHF). The performance of the MoOx–Cu/TiO2 catalysts was comparable to those modified with either Ag or Au instead of Cu. Upon the combination of two Mo precursors, i.e. (NH4)6Mo7O24 and Na2MoO4, the selectivity of the catalyst (MoOx–Cu–Na/TiO2) was further enhanced to achieve 81% yield of 2,5-DHF. This catalyst also exhibited broad substrate scope including cyclic and linear alkyl vicinal diols and tartaric ester. Furthermore, MoOx–Cu–Na/TiO2 was reusable at least three times after its calcination as regeneration. The reaction was almost zero-order with respect to the H2 pressure and 1,4-AHERY concentration, suggesting that the release of the alkene is the rate-determining step. The comprehensive characterization using STEM, XRD and XAFS provided insights into the surface structure of the catalyst, revealing that H2 is activated over Cu particles and subsequently transferred to Mo cluster species on the TiO2 surface via the spillover effect to proceed with the DODH reaction.
期刊介绍:
Green Chemistry is a journal that provides a unique forum for the publication of innovative research on the development of alternative green and sustainable technologies. The scope of Green Chemistry is based on the definition proposed by Anastas and Warner (Green Chemistry: Theory and Practice, P T Anastas and J C Warner, Oxford University Press, Oxford, 1998), which defines green chemistry as the utilisation of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products. Green Chemistry aims to reduce the environmental impact of the chemical enterprise by developing a technology base that is inherently non-toxic to living things and the environment. The journal welcomes submissions on all aspects of research relating to this endeavor and publishes original and significant cutting-edge research that is likely to be of wide general appeal. For a work to be published, it must present a significant advance in green chemistry, including a comparison with existing methods and a demonstration of advantages over those methods.