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."
* RELATED_TOPICS
o Matter_&_Energy
# Alternative_Fuels # Organic_Chemistry # Chemistry #
Engineering_and_Construction # Inorganic_Chemistry #
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* RELATED_TERMS
o Oxidizing_agent o Catalysis o Autocatalysis
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Weapons_of_mass_destruction o Salicylic_acid

========================================================================== 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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