Review Article
Ammonia Synthesis over an Iron Catalyst with an Inverse Structure: A Comprehensive Review
Tsiye Tekleyohanis Hailemariam*
Issue:
Volume 13, Issue 4, August 2025
Pages:
76-82
Received:
15 July 2025
Accepted:
25 July 2025
Published:
13 August 2025
Abstract: Ammonia synthesis is a cornerstone of the chemical industry, critical for fertilizer production and global food security. The Haber-Bosch process, relying heavily on iron-based catalysts, has been optimized over the decades. However, conventional catalysts still face limitations related to reaction conditions, energy efficiency, and catalyst deactivation. This review focuses on recent advances in inverse structured iron catalysts a novel configuration where the support encapsulates the active iron phase, reversing the conventional catalyst design. This inverse approach promises improved dispersion, enhanced surface properties, and increased resistance to sintering and poisoning. The review explores the synthesis methods, structural characterization, mechanistic insights, and catalytic performance of inverse iron catalysts, comparing them with traditional systems. Finally, it addresses current challenges and outlines future directions in the development of sustainable and efficient ammonia synthesis technologies.
Abstract: Ammonia synthesis is a cornerstone of the chemical industry, critical for fertilizer production and global food security. The Haber-Bosch process, relying heavily on iron-based catalysts, has been optimized over the decades. However, conventional catalysts still face limitations related to reaction conditions, energy efficiency, and catalyst deacti...
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Research Article
Comparative Study of the Physicochemical Properties of Petroleum Products Sold in the Republic of Congo: The Case of Lubricants
Ulrich Berry*,
Westinevy Benarez Ndzessou,
Laurette Brigelia Nkeletela,
René Evrard Josué Samba,
Ermelan Makaya Poaty
Issue:
Volume 13, Issue 4, August 2025
Pages:
83-96
Received:
7 August 2025
Accepted:
19 August 2025
Published:
23 September 2025
DOI:
10.11648/j.ajche.20251304.12
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Views:
Abstract: Petroleum products play a vital role in global economic development and are fundamental to numerous industries as well as daily life. They are commonly used in transportation (as fuels) and in the petrochemical industry for the production of first- and second-generation synthesis intermediates. The most common petroleum products include gasoline, diesel fuels, liquefied petroleum gases (LPG), and lubricants. These products must meet sales standards and specifications to ensure optimal performance and environmental compliance. This study focuses exclusively on lubricants. Among the key properties required for petroleum products are: the octane number for gasoline, the cetane index for diesel, flash point, freezing point, density, vapor pressure, viscosity, and volatility. However, this study concentrates solely on the physicochemical properties of lubricants. Specifically, it investigates their density, relative density, viscosity, and pH which constitute the main objective of this research. The quantities analyzed were measured using standard laboratory equipment such as a precision balance, test tubes, pH paper, and a Hoppler-type viscometer (ball viscometer). All lubricant samples were collected from fuel stations and various informal vendors in Brazzaville, Republic of Congo. The results of the analyses indicate that lubricants sold at fuel stations are denser than those sold by informal vendors. Furthermore, station-sold lubricants are typically yellow in color, while those from informal sources range from light yellow to pink, and tend to exhibit slightly less stable viscosity levels.
Abstract: Petroleum products play a vital role in global economic development and are fundamental to numerous industries as well as daily life. They are commonly used in transportation (as fuels) and in the petrochemical industry for the production of first- and second-generation synthesis intermediates. The most common petroleum products include gasoline, d...
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