MSGID: 1:317/3 640ab26f   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    A safe synthesis of hydrogen peroxide inspired by nature    
    A new homogeneous catalyst enables the safe and direct synthesis of   
   hydrogen peroxide    
      
     Date:   
         March 9, 2023   
     Source:   
         Kyushu University   
     Summary:   
         Scientists report the safe synthesis of hydrogen peroxide   
         (H2O2), an oxidizing agent used in multiple industries including   
         semiconductors, using a new rhodium-based catalyst. The catalyst   
         is based on natural enzymes found in extremophile microorganisms,   
         and the reaction meets three chemical ideals for H2O2 production:   
         safe, use of a single vessel, and direct synthesis.   
      
      
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   FULL STORY   
   ==========================================================================   
   Hydrogen peroxide is a ubiquitous chemical found in most homes and   
   used in everything from dying hair to treating wounds. It is also an   
   invaluable agent for many industries from food, textiles, and even in   
   semiconductor production.   
      
      
   ==========================================================================   
   Reporting in JACS, researchers at Kyushu University have developed a new   
   process to synthesize this chemical utilizing a new homogeneous catalyst   
   inspired by nature. Moreover, the process is significantly safer than   
   conventional methods.   
      
   Scientists have been reporting the synthesis of hydrogen peroxide for more   
   than two hundred years. Today's industry standard is a method known as   
   the 'anthraquinone method,' a stepwise and indirect process that dates   
   back to World War II. However, while hydrogen peroxide -- or H2O2 --   
   itself is relatively harmless, its production sometimes is not.   
      
   "Current synthesis methods are wasteful. This is a result of the high   
   flammability of the hydrogen and oxygen mixtures and the requirement of   
   varying materials," explains Professor Seiji Ogo from Kyushu University's   
   Faculty of Engineering, who authored the study.   
      
   Ogo and his team have been seeking a greener approach for H2O2production,   
   looking to nature for inspiration. They focused particularly on a set of   
   enzymes called 'hydrogenases.' These are enzymes found in extremophile   
   microorganisms -- organisms that live in extremely hostile environments,   
   like the very bottom of the ocean.   
      
   Another location of extremophile activity is the hot springs   
   of Japan. This is where Ogo and colleagues found hydrogenase   
   S-77. Hydrogenases show promising properties for the transfer of electrons   
   from hydrogen to oxygen molecules, a key event for the synthesis of   
   hydrogen peroxide.   
      
   "Hydrogenase S-77 was the source of inspiration for previous work in my   
   lab, where we constructed a rhodium-based homogeneous catalyst," explains   
   Ogo. "The catalyst worked by facilitating the withdrawal of electrons from   
   hydrogen molecules and then donating them to oxygen molecules. However,   
   it gave a poor yield."  In their new study, the catalyst was improved by   
   incorporating a N-heterocyclic carbene ligand for the reduction stage,   
   which led to a turnover number -- a reflection of the efficiency of the   
   reaction -- more than 250 times higher that of the previous catalyst,   
   and one of the highest ever reported for a homogeneous catalyst.   
      
   Further, unlike the conventional anthraquinone method, the new homogeneous   
   catalyst requires only one step and no separation of hydrogen and oxygen   
   gas from the reaction flask. Therefore, with more development, the new   
   catalyst could lead to a process that demands less material and lower   
   costs at industrial levels.   
      
   "The new process is an ideal reaction for hydrogen peroxide synthesis   
   because it involves a safe reaction mixture, reaction in one vessel,   
   and direct synthesis using only hydrogen and oxygen," concludes   
   Ogo. "Companies are always seeking ways to lower production costs. Our   
   catalyst may be an important resource for many industries."   
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   ==========================================================================   
   Story Source: Materials provided by Kyushu_University. Note: Content   
   may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Seiji Ogo, Takeshi Yatabe, Tamon Tome, Riko Takenaka, Yoshihito   
      Shiota,   
         Kenji Kato. Safe, One-Pot, Homogeneous Direct Synthesis of   
         H2O2. Journal of the American Chemical Society, 2023; 145 (8):   
         4384 DOI: 10.1021/ jacs.2c13149   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/03/230309124950.htm   
      
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