Research Article
Study of Electrochemical Behavior of Drug Interaction Between Azithromycin and Hydroxychloroquine on Carbon Paste Modified Metal Film Electrode and Local Clay
Bakary Tigana Djonse Justin*,
Alfred Sisinvou,
Bopda Aurelien,
Zang Akono Adam Ramses,
Paul Nestor Djomou Djonga
Issue:
Volume 9, Issue 2, December 2025
Pages:
48-56
Received:
8 July 2025
Accepted:
18 July 2025
Published:
27 October 2025
Abstract: In this study, a carbon graphite-clay paste electrode (CPEA) was proposed to study the electrochemical behavior of drugs such as azithromycin (AZI) and hydroxychloroquine (HYC). The electrochemical analysis was carried out by cyclic voltammetry (VC) in the potential range [-0.03; 0.35 V], in a phosphate buffer solution (0.1 M; pH = 6.4). It is in this logic that before the elaboration of the carbon graphite-clay composite, the clay powder was prepared and its structural and textural properties were examined by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM). The results indicate that the electrode was effectively modified. The electrode was then subjected to electroanalysis at the same concentrations (3 mM) for individual and combined AZI, HYC, and AZI+HYC. However, in the presence of analyte, the phenomena are irreversible, with oxidation phenomena dominating. The electroactivity of the drugs used concerns the hydroxyl groups, observed around 0.18 V. Furthermore, an interaction study in the analytical application was conducted and it was found that the electroanalytical method used can be well adopted for the simultaneous electrochemical detection of HYC and AZI.
Abstract: In this study, a carbon graphite-clay paste electrode (CPEA) was proposed to study the electrochemical behavior of drugs such as azithromycin (AZI) and hydroxychloroquine (HYC). The electrochemical analysis was carried out by cyclic voltammetry (VC) in the potential range [-0.03; 0.35 V], in a phosphate buffer solution (0.1 M; pH = 6.4). It is in t...
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Research Article
Kinetic Parameter Optimization and By-product Analysis in N-butane Oxidation to Maleic Anhydride in an Industrial Fixed-bed Reactor
Ervin Karic*
,
Ivan Petric
Issue:
Volume 9, Issue 2, December 2025
Pages:
57-66
Received:
7 November 2025
Accepted:
18 November 2025
Published:
29 December 2025
DOI:
10.11648/j.ajcbe.20250902.12
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Abstract: Maleic anhydride is a key intermediate in the chemical industry, predominantly produced through the partial oxidation of n-butane over vanadium-phosphorus-oxide (VPO) catalysts. This reaction is accompanied by side reactions that lead to the formation of undesired by-products, primarily CO and CO2. In this work, a previously developed mathematical model of a fixed-bed tubular reactor was extended to include a catalyst activity function accounting for catalyst deactivation, and the kinetic parameters were optimized using experimental data from an industrial reactor at Koksara d.o.o. Lukavac. The model describes the partial oxidation of n-butane to maleic anhydride through multiple reactions, with reaction rates expressed as functions of temperature, partial pressures, and catalyst activity. Numerical simulations were performed using MATLAB, employing a nonlinear least-squares solver to minimize the deviation between the predicted and measured temperature profiles along the reactor. The validated model showed good agreement with experimental data, demonstrating its capability to accurately simulate reactor behavior under typical industrial conditions. Parametric studies were conducted to analyze the effects of inlet n-butane and oxygen flow rates, reaction mixture temperature, and pressure on the formation of CO and CO2. The results indicate that by-product formation is strongly influenced by the oxygen/n-butane ratio, temperature, pressure, and the catalyst oxidation state. Higher oxygen flow rates and elevated temperatures increase CO and CO2 formation, while lower values reduce their production. Changes in n-butane flow have a minor effect on CO2, but more pronounced effects on CO due to the interplay between partial and complete oxidation at different catalyst sites. Increasing the inlet pressure enhances by-product formation by increasing reactant concentrations, whereas reduced pressure decreases CO and CO2 formation. The developed model provides a practical tool for understanding and optimizing industrial maleic anhydride production. It offers insights into the effects of key process parameters on by-product formation, supporting improved reactor operation, reduced trial-and-error experimentation, and more efficient industrial process design.
Abstract: Maleic anhydride is a key intermediate in the chemical industry, predominantly produced through the partial oxidation of n-butane over vanadium-phosphorus-oxide (VPO) catalysts. This reaction is accompanied by side reactions that lead to the formation of undesired by-products, primarily CO and CO2. In this work, a previously developed mathematical ...
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